application reference number: wwo10001 tunnel … and bridge assessments ... the bridge is supported...

Tunnel and Bridge AssessmentsCentral ZoneAssessment of the Effects of Tunnel Induced Settlement on Waterloo Bridge Structure No. BR015Doc Ref: 9.15.46

Folder 98 September 2013DCO-DT-000-ZZZZZ-091500

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Thames Tideway Tunnel Thames Water Utilities Limited

Application for Development ConsentApplication Reference Number: WWO10001

Assessment Report Page 1 16/09/2013

Thames Tunnel Detailed Bridge Assessments

Assessment Report

List of contents

Page number

1 Executive Summary ......................................................................................... 3

2 Introduction ...................................................................................................... 5

3 Structure Details .............................................................................................. 6

3.1 Superstructure ......................................................................................... 6

3.2 Substructure ............................................................................................ 7

3.3 Articulation ............................................................................................... 8

3.4 Spans ...................................................................................................... 8

3.5 Parapet .................................................................................................... 8

3.6 Joints ....................................................................................................... 8

3.7 Surfacing ................................................................................................. 9

3.8 Drainage .................................................................................................. 9

3.9 Services ................................................................................................... 9

3.10 Record information .................................................................................. 9

3.11 Maintenance and Modifications ............................................................... 9

4 Inspection for Assessment Findings ........................................................... 10

4.1 Purpose ................................................................................................. 10

4.2 Methodology .......................................................................................... 10

4.3 Superstructure ....................................................................................... 10

4.4 Substructure .......................................................................................... 10

4.5 Foundations ........................................................................................... 10

4.6 Conclusions and Recommendations ..................................................... 11

5 Assessment Methodology ............................................................................. 12

5.1 Calculation of Settlement Trough .......................................................... 12

5.2 Application of Settlement ....................................................................... 12

5.3 Calculation of Section Capacities .......................................................... 12

5.4 Modelling of the Structure ...................................................................... 13

5.5 Utilities & Drainage ................................................................................ 15

6 Assessment results summary ...................................................................... 16

6.1 Superstructure & Foundations ............................................................... 16

6.2 Utilities ................................................................................................... 21


7 Discussion of Results and Conclusions ...................................................... 22


7.2 Utilities ................................................................................................... 26

8 Recommendations ......................................................................................... 27


8.2 Utilities ................................................................................................... 27

APPENDIX 1 – Approval in Principle .................................................................... 28

APPENDIX 2 – Inspection Report .......................................................................... 29

APPENDIX 3 – Predicted Settlement Troughs ..................................................... 30

APPENDIX 4 – Assessment Calculations ............................................................. 31


1 Executive Summary

AECOM has been commissioned by Thames Tunnel to carry out an assessment of the effect the proposed tunnel would have on Waterloo Bridge. This forms part of the 3b detailed Bridge Assessments for impact of proposed tunnelling works for the Thames Tunnel project.

Originally constructed between 1937 and 1942, Waterloo Bridge is a 423m long, 25.3m wide, seven span reinforced concrete cantilever box girder bridge. The bridge is supported on abutments at the north and south, four monolithic river piers and two monolithic shore piers. The Grade II listed structure carries the A301 over the River Thames and Victoria Embankment (A3211).

Information and record drawings of the structure were provided by the asset manager, The City of Westminster, for review. Following this review a Greenfield settlement analysis and inspection for assessment were undertaken.

The inspection for assessment (doc. No. 314-RI-TPI-BR015-000001, see Appendix 2) was carried out on the 27th October 2011. Generally the bridge was in a fair condition with some minor signs of deterioration. Minor areas of spalling were observed to the underside of the bridge, corroded reinforcement was visible in some of these areas. Large areas of rust staining were present around the half joint, it was not clear if the rust is originating from reinforcement adjacent to the half joint or the half joint itself. Rust spots on the soffit indicate some reinforcement corrosion is occurring on the structure. A condition factor of 1.0 was applied to all structural members in the assessment of Waterloo Bridge.

The assessment has been undertaken in accordance with the Approval in Principle document No. 314-EA-TPI-BR015-000001 (see Appendix 1). The structure was modelled as a linear-elastic three dimensional shell and beam model in the LUSAS Finite Element program. Due to the sensitivity of this type of structure to settlement, and the importance of the structure to be considered, settlements were considered in a detailed assessment in combination with the following loads, when a section is over 2.5% ULS capacity; 40t Assessment live load represented by HA type UDL and KEL applied in accordance with BD21/01 and BD101/11 and HB live loading in accordance with BD37/01. Footway loading in accordance with BD21/01 has also been applied.

The ground settlement was applied to the affected piers in the model as displacements. The effect of the displacements, dead loads and live loading on the modelled members of the structure was compared against their sectional capacities (see calculations in Appendix 4), i.e. utilisation = applied stress / ultimate stress.

With the exception of the pier bearing walls, the sectional stress increase identified in the settlement assessment is less than what would be considered to be significant. As the pier bearing walls exhibited a marked increase in applied force, as a result of the settlement only loadcase, these elements were checked with regard to live loading. It was found that under a number of live load combinations some areas of the bearing wall


had a utilisation above their ULS capacity. Combinations where live loading was combined with settlement effects showed a reduction of working load in the bearing walls, this indicates the slight settlement and rotation, as a result of the tunnelling construction, would be load-relieving.


2 Introduction

AECOM has been commissioned by Thames Tunnel to carry out an assessment of Waterloo Bridge. This forms a part of the Sub-Package 3b of the Detailed Bridge Assessment contract, for impact assessment of proposed tunnelling works, for the Thames Tunnel project.

The main objective of the project is to identify any structural or serviceability implications that may result from proposed tunnelling works in vicinity of the existing infrastructure.

Waterloo Bridge is a reinforced concrete, multi-span highway bridge. Originally constructed between 1937 and 1942, Waterloo Bridge is a 427m long, 25.3m wide, seven span reinforced concrete cantilever box girder structure. The bridge is supported on abutments at the north and south, four monolithic river piers and two monolithic shore piers. The Grade II listed structure carries the A301 over the River Thames and Victoria Embankment (A3211). Spans and piers are numbered from the north end of the structure.

The structure is located on Ordnance Survey grid reference TQ307805.

Figure 1 Proposed Thames Tunnel alignment under span 2 of Waterloo Bridge

Figure 1 shows the proposed tideway tunnel under span 3 of Waterloo Bridge, with span 1 being the most northerly span. It can be seen that the proposed tunnel is located equal distance from each pier.

Structural details used for the assessment were retrieved from information and drawings provided by the managing authority of the Bridge, The City of Westminster. After reviewing these details an inspection for assessment was performed to verify the condition of the structure.


Settlement of the ground due to the proposed tunnelling was calculated using a Greenfield Settlement analysis. The analysis of the structure was conducted in the LUSAS finite element program using a three dimensional shell and beam model, with the calculated settlements applied at foundation level of the affected piers. The resultant effects were compared against the sectional capacities of the members and a utilisation was calculated.

3 Structure Details

3.1 Superstructure

The deck is made up of two box sections that consist of three cells. Each box is 7.62m wide and varies in height from 2.29m at the mid-span to 6.71m at the shore piers and 7.54m at the river piers. There are diaphragms in the box girders spaced at 3.85m centres.

Photograph 1 Underside Waterloo Bridge showing main structural details

Spanning transversely between the two boxes are 10.06m long cellular reinforced concrete (RC) beams that support RC slabs. The cellular beams are 1.98m deep and coincide with the spacing of the diaphragms. The RC slabs have a maximum thickness of 380mm.

The central 28.6m of span 4 is a drop-in span. The drop-in deck section is articulated from the continuous deck by expansion joints located in the half joint. The expansion joints are of the single segmental roller-bearing type. The bridge is designed for a total change in length of 152mm distributed equally between the 4 expansion joints i.e. abutments and drop in span half joints. The main roller-bearings are limited in width to the thickness of the deck box webs. Medium high-tensile steel has been used, with a steel roller diameter of 1016mm. The principal compression component force at


the drop-in span half joint is transferred from the bearing billets by means of 4No. mild steel shear plates. The main tensile component at the joint is resisted by medium high-tensile post-tensioned bars.

The bars are contained within steel tubes and fitted with projected end connections. After the surrounding concrete had hardened steam was passed through the tubes, the thermal expansion was taken up by turning the turnbuckles so that upon cooling the bars would be at the required stress of 207 N/mm2. After stressing, the bars were grouted up in their tubes. Secondary roller-bearings in the deck and box girder bottom flange are provided to limit transverse deflections and maintain the vertical rollers in a stable position by transmitting torsion forces from torsional deflection across the joint, allowing the whole span to act torsionally as if monolithic. The northern section of the bridge spans from the north abutment monolithically with pier 1, pier 2 and pier 3. This section also cantilevers south of pier 3 to the drop-in span, in span 4. The southern section of the bridge spans from the south abutment monolithically with pier 6, pier 5 and pier 4. This section also cantilevers north of pier 4 to the drop-in span, in span 4. The shore cantilevers beyond pier 1 and pier 6 are 23.4m long and the cantilevers in span 4 are 23.9m. The end of the abutment cantilevers are counterbalanced with cast iron kentledge weighing 570 tons in total. The connection to the abutments is achieved by a short RC slab connected to a steel knuckle joint on the end of the bridge deck and to recently installed elastomeric bearings on the abutment shelves on the approach structures.

At the end of the centre span cantilevers 63 tons of cast iron kentledge is positioned. Medium high-tensile steel pre-stressed bars are located in the vicinity of the shore cantilevers above the bearing walls, these are stressed in the same way as the span 4 half joint bars. The pre-stressing is provided to control local high shear stresses.

The sides of the deck are faced with Portland Stone panels.

3.2 Substructure

The piers are of reinforced concrete construction and consist of a bearing wall, which is monolithic with the deck box-sections, surrounded by an RC shell, with a total width of 32.39m, height of approximately 13.5m and a maximum thickness of 4.27m. The bearing walls are 686mm thick and are approximately 13.5m high. The flexibility of the bearing walls, being monolithic with the deck and the foundations, act horizontally as spring supports. As designed these are balanced between the north and south sections of the bridge to induce equal movements at each joint. The shell wraps around the piers and is stiffened with vertical and horizontal ribs. The function of the pier shell is to withstand impact forces, act as a permanent coffer dam to the bearing wall, should they need maintenance, and restrict extreme movements of the bridge superstructure via stone pads located at the top of the shell. The ribs on either side of the bearing walls are connected with steel ties that pass through the bearing walls. The voids between the bearing wall and shell ribs allow water to fill the inside of the pier to counteract the hydrostatic pressure on the outside of the shell. The bearing walls and shells are connected to cellular RC bases


2.44m high, 32.39m wide and 4.27m thick. The piers are clad with granite on the lower section and clad with Portland stone on the upper.

The shore piers are of similar construction to the river piers but have a height of approximately 11.85m and a maximum thickness of 3.80m. Between the two box girders, the pier is 8.1m high. The bearing wall of the shore piers is 572mm thick. The bearing wall and shell sit on an RC cellular base similar to the river piers. The piers are enclosed within a Portland stone clad enclosure to the north and within the National Film Theatre to the south.

3.3 Articulation

The bridge deck is monolithic with the piers, with a drop-in deck section in span 4. There are knuckle expansion joints between the drop-in deck section and the continuous deck. A steel knuckle joint on the end of the bridge deck connects to a 4m, length, cast approach slab which connects, via recently installed elastomeric bearings, to the abutment shelves on the approach structures. The approach slab is connected to the shore cantilevers via an elastomeric joint.

3.4 Spans

Waterloo Bridge has 7No. spans: The North span 1 crosses the Buddha Bar while span 2 crosses both Victoria Embankment and a section of the River Thames. While the South span 7 provides a vault which now houses the British Film Institute, span 6 crosses the South Bank pedestrian footway and a section of the River Thames. The remaining 3 spans cross the river only. Spans will be referred in the assessment process as follows:

North Shore Cantilever L1 = 23.7m

North Bank Span L2 = 73.184m

River Span 3 L3 = 76.302m



South Bank Span L6 = 73.184m

South Shore Cantilever L7 = 23.7m

3.5 Parapet

The parapets are approximately 1.2m high and consist of metallic railings founded on a Portland Stone base and cornice.

3.6 Joints

There are expansion joints between the approach slabs and the abutment cantilevers. Also, longitudinal expansion joints are located along the east and west sides of both of the shore cantilevers. Two expansion joints are also located in span 4 on either side of the simply supported section of deck; see section 3.1 for a detailed description.

Longitudinal movements are accommodated by single segmental roller-type bearings, elastomeric joints and flexure of the monolithic bearing


walls. The deck is articulated by knuckle joints in the half joints in span 4 and elastomeric joints at the abutments, as well, as rotations allowed for by flexure of the bearing walls.

3.7 Surfacing

From archive drawings the concrete deck has approximately 165mm depth of surfacing layers in the carriageway. The carriageway has two lanes in either direction separated by concrete kerb stones and an artificial stone central reservation. The footways are separated from the running lanes by granite kerbstones.

3.8 Drainage

Surface drainage is provided by a gully system running adjacent to both carriageway granite kerbs. Surface water is collected by the gullies which feed the surface water to drainage pipes running through the deck and down through the piers.

3.9 Services

Based on archive information there are two groups of communication cables carried by the bridge, consisting of BT communication cables and fibre optic cables.

3.10 Record information

There is a limited set of archive drawings available for the structure. The assessment has been mainly based in this case on “contract drawing” drawings and “The New Waterloo Bridge” document by Ernest J Buckton and John Cuerel provided by the City of Westminster. No “as built” drawings are available.

3.11 Maintenance and Modifications

No maintenance or modification information was located for the structure, although we are aware of a recent maintenance contract being undertaken on the bridge by FM Conway we do not have a record of the work that was carried out.


4 Inspection for Assessment Findings

4.1 Purpose

AECOM has been commissioned by Thames Tunnel to carry out an assessment of Waterloo Bridge. This forms a part of the Sub-Package 3b of the Detailed Bridge Assessment contract, for impact assessment of proposed tunnelling works, for the Thames Tunnel project.

4.2 Methodology

Inspection of the bridge was undertaken on the 27/10/2011 by AECOM.

The main objective of the project is to identify any structural or serviceability implications that may result from proposed tunnelling works in the vicinity of the existing infrastructure. The inspection for assessment has been focused specifically at the elements that could potentially be affected by the proposed Thames Tunnel construction. However, inspection of other elements was undertaken as well and observations included for asset owner’s consideration.

Below a brief summary is presented. More details relating to observations made during the inspection work are included in Appendix 2.

4.3 Superstructure

The main structural elements were observed to have similar faults; minor cracking, localised spalling and mild corrosion to the exposed reinforcement.

The rust staining spots found on the soffit of the deck and main box girders suggests that water is percolating through the deck. The staining on the soffits of the main box girders adjacent to the half joints is a clear indication of the joints’ permeability. A number of areas of spalling were observed on the cross girders in all spans. There are a number of spalled areas to the internal webs of the box girders also, with exposed and corroding reinforcement. Large areas of minor cracking to the internal webs of the box girders were also noted. Pedestrian footways were found to be in a poor condition with large areas of isolated cracking to the paving slabs.

4.4 Substructure

The visible areas of the piers were found to be in a good general condition. Organic growth was found around the waterline. A number of areas of light spalling and surface wear were found around the edges of the masonry cladding on the piers. The visible areas of the abutments were found to be in a good condition.

4.5 Foundations

The foundations could not be inspected at the time of the inspection. However, no evidence of foundation failure was observed in the above ground structure, indicating the foundations are in a good condition.


4.6 Conclusions and Recommendations

Generally the bridge was in a fair condition with some minor signs of deterioration.

Minor areas of spalling were observed to the underside of the bridge, corroded reinforcement was visible in some of these areas. Large areas of rust staining were present around the half joints, it is not clear if the rust is originating from reinforcement adjacent to the half joint or the half joint itself. Rust spots on the soffit indicate some reinforcement corrosion is occurring on the structure.

Based on the condition of the structural members inspected a condition factor of 1.0 will be applied to all structural members in the assessment of Waterloo Bridge. For a detailed description of the inspection and conclusions refer to Appendix 2.


5 Assessment Methodology

This assessment has been undertaken in accordance with the Approval in Principle document No. 314-EA-TPI-BR015-000001-AF, included in Appendix 1. Ground movements calculated from the Greenfield settlement analysis are applied at the foundation level of the modelled structure. The resultant load effects on the structure are compared against sectional capacities of the relevant members. Due to the sensitivity of this type of structure to settlement, and the importance of the structure to be considered, the settlements will be considered in a detailed assessment in combination, where required, with the following loads; 40t Assessment live load represented by HA type UDL and KEL are to be applied in accordance with BD21/01 and BD101/11 and HB live loading in accordance with BD37/01. Footway loading in accordance with BD21/01 will also be applied.

5.1 Calculation of Settlement Trough

Site ground conditions were identified from borehole logs obtained from the British Geological Society and Thames Tunnel. This information was used along with the proposed tunnel size and alignment in a Greenfield settlement analysis to produce the settlement troughs (see Appendix 3).

5.2 Application of Settlement

Load applied to the structure was in a form of displacements of the piers induced by the settlement of the soil. The calculated settlement trough was applied to the substructure at the base of foundation level, based on the current tunnel alignment. The length of the Waterloo Bridge piers results in a slight variation in settlement across the section of the piers.

The transverse settlement, or the bow wave effect, causes differential settlement across the width of the piers. This means the piers rotate transversely resulting in twisting of the deck spans. In the three dimensional model the transverse settlement has been applied at the base of the modelled caisson on each outer edge. The associated longitudinal vertical displacement and longitudinal rotations that occur have not been modelled as these effects are included in the permanent state model.

5.3 Calculation of Section Capacities

When calculating the ultimate capacity of a section, the factor γf3 = 1.1 has

been included for all elements along with the appropriate γm for the material (from BD 21). See appendix 4 for full details.

A condition factor of γc = 1.0 has been assumed in the assessment of all elements. This is justified as the structure is, in general, without any major signs of distress. For full Inspection Report refer to Appendix 2.

Member capacities have been calculated with use of SAM-LEAP, hand calculations (Appendix 4) and published capacity tables.


5.4 Modelling of the Structure

Two 3D shell and beam bridge models have been created in LUSAS modeller. The first is used to assess the permanent longitudinal settlement effects, live load effects and Bow wave settlement effects. The second to assess the bow wave effect on the span 4 drop-in half joint. The models have been constructed using QTS4 thick shell elements, and BMS3 beam elements for cross girders. BMS3 elements are straight beam elements in 3D for which shear deformations are included. The geometric properties are constant along their length. QTS4 elements are from a family of shell elements for the analysis of arbitrarily thick and thin curved shell geometries, including multiple branched junctions. The element formulation takes account of membrane, shear and flexural deformations.

All shell elements have been placed geometrically at the centre of the section they are to model. Thick shell elements have been chosen as these elements allow for through-thickness shear deformation calculations, and, through-thickness shear stress outputs in LUSAS. As the depth of box girder top and bottom flange is relatively thick, it is felt that these outputs will be significant when evaluating the induced tunnel settlements. Where section properties vary with length, such as the box girder bottom flange, the geometric properties of these sections will be averaged or a ‘worst case’ section will be used.

The pier shells do not contribute to the normal load path of the structure. Therefore, these have not been modelled as it is believed they may skew the results obtained from the assessment. Displacements of the foundations have been taken directly from settlements of the soil settlement trough and applied to nodes at the base of the caissons. If horizontal deflections are found to be greater than the 152mm then the deflection will be restricted to this in the model to replicate the limit stop.

A two span section has been modelled. This is so that one pier base can be fixed while the remaining two piers are deflected under longitudinal and transverse settlements. As the tunnel runs equidistance from each pier, the adjacent piers will both settle and rotate by the same magnitude. The deck sections at the south of the modelled spans have not been considered for the permanent longitudinal settlement effects, live load effects and Bow wave, seen in Figure 2. This is because the greatest longitudinal bending will be observed in span three and the greatest twist in the deck will be seen in span two. The extra drop in section, in span 4, has been modelled to assess the half joint, as shown in Figure 3. The settlement has been applied directly from the settlement troughs to the outer edges of the pier caissons affected. All member connections are assumed to be rigidly connected.


Figure 2 3D plate model of North section in LUSAS

Figure 3 3D plate model with drop-in section in LUSAS

For settlement only effects; moments, forces and stresses will be extracted from each model and compared with ULS capacities of the section in question, any stresses above a 2.5% ULS capacity will be assessed with regard to live loading and discussed in section 7. For settlement effects combined with live loading, moments, forces and stresses will be extracted from the model and compared to section capacities of the section in question, any stresses above 100% ULS will be discussed in section 7. Stresses in the half joint, as a result of the Bow Wave effect, will be compared against likely service loadings to gauge the settlement effect on the connection.

All concrete elements of the structure have been assessed in accordance with BD21/01, BD37/01 and BD101/11 respectively and also using BS5400.

The assessment has been based on the following material assumptions:

Concrete: 35 N/mm2

Steel: 250 N/mm2 (reinforcement)


5.5 Utilities & Drainage

Where services and utilities in the bridge are deemed to be sensitive to the effects of the proposed tunnelling work they will be assessed quantitavely. Those utilities that are likely to be affected are those constructed of stiff, brittle materials (e.g. Cast Iron).

The assessment will apply the deflections from the relevant areas of the analysed structure to the identified utilities and services to calculate the change in stress.


6 Assessment results summary

6.1 Superstructure & Foundations

The following tables summarise the results obtained during the assessment process. Detailed calculations are included in Appendix 5 of this report.

The Utilisation shown below, expresses the ratio of factored load effects divided by the ultimate capacity of the element and is derived from the following equation:

Utilisation = LoadEffect

SectionCapacityx100%

Where results for elements indicate utilisations greater than 2.5%, these sections will be assessed with regard to live loading, and discussed in the next section of this report.

Section Item Capacity App 1.7% Util 1.7% App 1.0% Util 1.0%

Upper

Bearing

Wall

Axial 12439588 13155 10.3

7898 6.1

Bending 863361 -88899 -53059

Shear 2767112 35202 1.3 21738 0.8

Lower

Bearing

Wall

Axial 11068613 3813 15.5

2289 9.4

Bending 472967 73425 12619

Shear 2767112 20689 0.7 12619 0.5

ABT

Bearing

Wall

Axial 9282763 65 0.0

39 0.0

Bending 397413438 9401 5640

Shear 2307271 -2393 0.1 -1436 0.1

Deck Slab

Section Bending 382937 -330 0.1 -197 0.1

Shear 163837 699 0.4 417 0.3

Top Flange

Over Piers

Bending 613102 423 0.1 252 0.0

Top Flange

Over

Midspan

Bending 623185 259 0.0 156 0.0

Bottom

Flange

Over Piers

Bending 1616383 9010 0.6 5376 0.3

Bottom

Flange

Over

Midspan

Bending 990306 674 0.1 405 0.0

Outer Web

Sections

Piers

Shear 797883 1196 0.1 714 0.1


Internal

Web

Sections

Piers

Shear 797883 341 0.0 204 0.0

Inner Web

Sections

Midspan

Shear 1796911 504 0.0 303 0.0

Table 1 Waterloo Bridge, Assessment Summary; Settlement Only

It can be seen from Table 1, above, that the pier bearing walls were found to have a utilisation of greater than 2.5% for bending during the settlement only load case for both 1.0% and 1.7% volume loss. As per Section 5.4, these have been subjected to further analysis using both HA and HB loading combined with settlement effects. The results of this further assessment can be seen in the tables below.

The Utilisation shown below for settlements combined with dead load, super-imposed dead load and live loading effects expresses the ratio of factored load effects divided by ultimate capacity of the element and is derived from the following equation:

Utilisation = LoadEffect

Capacityγ�∗ γ

��

=FactoredLoadEffect

ULSCapacityx100%

Where results for elements indicate utilisations greater than 100%, these sections will be discussed in the next section of this report.

In order to judge the current stress state of the pier bearing walls; first they were assessed with dead loads and super-imposed dead loads only. The maximum moment found with coexisting shear force and axial force was used and a capacity of the section was calculated from a moment-axial diagram of the bearing wall section, as shown in Table 2.

Section Item Capacity DL+SDL+LL Util

Upper

Bearing

Wall

Axial 10686138 5190990 54.7

Bending 1435369 -785713

Shear 2767112 162078 5.9

Lower

Bearing

Wall

Axial 10723248 3981040 37.1

Bending 1164036 396074

Shear 2767112 106682 3.9

Upper Wall

Corners Axial 20888769 15589500

74.6

Bending 2213782 -1199500

Shear 2767112 -310852 11.2

Table 2 Waterloo Bridge; DL+SDL Only

Then, to get a reference for their working stress, a number of combinations of HA UDL and KEL combined with dead loads and super-imposed dead loads were assessed. The worst case found was span two


fully loaded with 6 lanes of HA UDL and a KEL placed at mid-span in each lane, these results can be seen in Table 3.


Upper

Bearing

Wall

Axial 5975975 5917490 99.8

Bending 1410701 -1408170

Shear 2767112 299174 10.8

Lower

Bearing

Wall

Axial 9581175 4485760 57.4

Bending 1194643 686076

Shear 2767112 186923 6.8

Upper Wall

Corners Axial 15866156 -17611600

116.8

Bending 1854379 -2165500

Shear 2767112 -568133 20.5

Table 3 Waterloo Bridge; DL+SDL+HA (Span 2 loaded)

It can be seen from Table 3 that the peak utilisations for the inner corners of the bearing walls, where the section attached to the deck spine beams joins to the main section of the bearing wall, are above 100% ULS. These will be discussed in Section 7.

To determine the effect the settlement has on the working stress in the bearing walls, 1.7% volume loss settlement was assessed in combination with dead loads, super-imposed dead loads and HA loading, the most onerous case is shown in Table 4, below. Full details of the assessment can be seen in Appendix 4.

Section Item Capacity DL+SDL+LL+1.7% Util

Upper

Bearing

Wall

Axial 6946374 5824040 95.6

Bending 1414180 -1352510

Shear 2767112 285463 10.3

Lower

Bearing

Wall

Axial 9841664 4345260 52.6

Bending 1186997 -624912

Shear 2767112 119227 4.3

Upper Wall

Corners Axial 16328866 -17361000

109.7

Bending 1899814 -2084470

Shear 2767112 -587848 21.2

Table 4 Waterloo Bridge; 1.7%VL+DL+SDL+HA (Span 2 loaded)



Upper

Bearing

Wall

Axial 11943367 5322660

44.6 Bending 1431322 -483432

Shear 2767112 118463 4.3

Lower

Bearing

Wall

Axial 11008359 4165960

37.8 Bending 1176724 317007

Shear 2767112 83915 3.0

Upper Wall

Corners Axial 22852125 16106500

70.5 Bending 2123482 734669

Shear 2767112 -100955 3.6

Table 5 Waterloo Bridge; 1.7%VL+DL+SDL+HA (Span 3 loaded)

Utilisation of the upper bearing wall corners can be seen to have reduced. However, Table 4 shows a utilisation greater than 100% and will therefore be discussed further in section 7.


Upper

Bearing

Wall

Axial 10672650 6213050

58.2 Bending 1397605 -788615

Shear 2767112 156773 5.7

Lower

Bearing

Wall

Axial 10837120 4620960

42.6 Bending 1198947 -364525

Shear 2767112 67381 2.4

Upper Wall

Corners Axial 20872465 18609300

89.2 Bending 1668794 -1203300

Shear 2767112 -360866 13.0

Table 6 Waterloo Bridge; 1.7%VL+DL+SDL+HA (Span 2 & 3 loaded)

As there are no weight restrictions on Waterloo Bridge, and in order to gain a fuller understanding of possible working loads on the structure, HB vehicle loads were considered in conjunction with HA loading, the results of which can be seen in tables 7 and 8.


Upper

Bearing

Wall

Axial 4816323 5953120 123.6

Bending 1409188 -1582640

Shear 2767112 335819 12.1

Lower

Bearing

Wall

Axial 9210251 4550140

64.1 Bending 1197360 767876

Shear 2767112 209751 7.6


Upper Wall

Corners Axial 14267590 17521700

130.5

Bending 1870755 -2440680

Shear 2767112 -597673 21.6

Table 7 Waterloo Bridge; DL+SDL+HA+HB (Span 2 loaded)

It can be seen that both the upper section of bearing wall and the upper bearing wall corners are far beyond their theoretical ultimate limit stress when assessed for HA and HB loading.

Section Item Capacity DL+SDL+LL+1.7 Util

Upper

Bearing

Wall

Axial 4816323 5945460 123.4

Bending 1409530 -1527430

Shear 2767112 321887 11.6

Lower

Bearing

Wall

Axial 9488956 4620940

59.0 Bending 1198947 706988

Shear 2767112 47292 1.7

Upper Wall

Corners Axial 14744037 17491500

125.7

Bending 1876216 -2359320

Shear 2767112 -618061 22.3

Table 8 Waterloo Bridge; 1.7%+DL+SDL+HA+HB (Span 2 loaded)

Again, application of the settlement effects into the model slightly reduces the utilisation of the bearing wall elements; this will be discussed in section 7.

Transverse induced, bow wave, settlements were calculated as being 1.1mm across the 36m transverse width of the piers. This leads to very minor rotations and twisting effects. As can be seen below, the induced effects are all less than 2.5% of the ULS capacity.

Section Item Capacity App 1.7% Util 1.7%

Deck Slab Section Bending 101790 358 0.35

Shear 100597 2352 2.34

Girder Top Flange

Over Piers

Bending 101363 -1325 1.31

Girder Top Flange

Midspan

Bending 120853 -1246 1.03

Girder Bottom

Flange Over Piers

Bending 264259 805 0.30

Girder Bottom

Flange Midspan

Bending 111913 260 0.23

Outer Web

Sections Piers

Shear 797883 -304 0.04


Internal Web

Sections Piers

Shear 797883 -748 0.09

Inner Web

Sections Pier

Shear 3263798 -12585 0.39

Table 9 Waterloo Bridge, Bow Wave Effects Summary

Transverse bow wave effects on the drop-in span half joint were analysed using the drop-in span model. The peak Von Mises stress and the peak resultant deflection magnitude were compared for three load cases;

1. 1.7% Bow wave settlement

2. One HB vehicle (6m central axis spacing) positioned in the centre of lane 1 on span 3

3. HA UDL and KEL, with UDL applied over lane 1 of span 3 and the KEL applied at the centre of lane 1 span 3

Loadcase Peak Von Mises Peak Rslt Disp

1.7% Bow Wave 0.244N/mm^2 1.46mm

One HB 1.038N/mm^2 9.89mm

One lane HA UDL +

KEL 0.876N/mm^2 8.26mm

Table 10 Waterloo Bridge, Peak Half Joint Effects

It can be seen from the table above that the peak Von Mises Stress induced for the 1.7% volume loss bow wave is approximately 4.25 times less than the single HB and 3.6 times less than one lane of HA. The peak resultant displacement at the half joint as a result of the 1.7% bow wave volume loss is approximately 6.8 times less than the single HB, and 5.7 times less than one lane of HA loading. The peak results show the bow wave effects to be minimal when compared to a fraction of the live loading which will be experienced by the bridge on a regular basis.

6.2 Utilities

Archive information from Thames Tunnel indicates that there are two groups of telecommunication cables running across Waterloo Bridge. Consisting of standard telecoms (BT) cables and fibre optic telecoms cables, which in nature are flexible, and as such, are not deemed to be at risk from tunnelling action induced settlements of the bridge.

Utility Description Quantitative Assessment Required

Telecoms Cables (BT) No

Fibre Optic Telecoms Cables No

Table 10 Waterloo Bridge services requiring quantitative assessment


7 Discussion of Results


7.1.1 Structure Behaviour

On first inspection it would appear that Waterloo Bridge would be susceptible to differential settlements, mainly due to the lack of expansion joints and bearings along its length and seemingly stiff main sections. However, the tops of the piers and inner bearing walls (Figure 4) are designed, such that, they are relatively less stiff than the surrounding structure. The piers are constructed from a number of components, mainly an inner bearing wall which is monolithic with the box girders and an outer pier shell. The reinforced concrete pier shell is tied together using steel bars running through the bearing wall. This form of construction allows the bearing wall to deflect inside the pier shells, meaning small longitudinal rotations and displacements of the piers can act and displace the bearing wall without transferring large stresses into the upper sections of the superstructure. A large amount of bending capacity is given up in order to achieve the flexibility in the bearing walls. To ensure the bearing walls do not excessively rotate and exceed their ULS bending capacity during normal loading, the bridge is effectively balanced with kentledge. This limits rotations.

Figure 4 Typical elevation of pier

The relatively large clear spans of Waterloo Bridge mean the piers are in the outer region of the influence zone of the proposed tunnel. This relates to small settlements and rotations observed at the base of the piers.

7.1.2 Bearing Walls

It can be seen from the results of the assessment that under normal working loads there are peak forces in the corners of the bearing walls in excess of their ULS capacity, area highlighted in Figure 5. One possible explanation for this is the positioning of the live load using the higher lane factors, determined in BD21/01, as these are located on the central two of the six notional lanes. This causes a concentration of loading at mid-width

of the bridge, between the main spine beams. This action creates a deflection of the deck and as the bearing walls deflect to accommodate this loading, the less stiff central section dishes in towards the loaded span, in a shear lag type effect.

Figure 5 Area of high stress in bearing wall

As the outer sections of the bearing wall are cast into the spine box beams, this area has a greater stiffness. This differential of stiffness is the root cause of a stress concentration at the corners of the bearing wall. Figure 6 shows the typical deformed shape of the bearing wall; note, for illustrative purposes the deflections are exaggerated.

To accommodate for this stress concentration the bearing walls have been designed with a large amount of steel reinforcement in this area. It is worth


noting that the assessment was made using peak moment forces in the section, and reality could mean that forces in the actual structure are lower than calculated from local model peaks. Forces peaks may be significantly higher than the general stress state of the elements. These peaks in output can occur due to coarseness of the mess, high variance in force interpolation between elements, lack of redistribution in an elastic model or a combination of the three. The structure is of continuous construction and not a series of finite elements, it will also exhibit elastic-plastic behaviour, so these effects may be smoothed and redistributed in the bridge giving much lower maximum force values.

Figure 6 Deflected shape of bearing wall and induced longitudinal moments

The assessment results indicate that the application of the soil settlement reduces the utilisation of capacity in the bearing walls in the worst of the tested loadcases. The minor displacement and rotation of the pier base alleviates some of the bending action, shown in Figure 6, in the bearing wall and reduces its induced stress.

Assessment using HB loading indicates the entire top of the bearing wall to be subjected to axial forces and bending forces much in excess of the bearing wall ULS capacity. No weight restriction is currently in force on Waterloo Bridge. However, in light of the findings of this assessment the asset owner may wish to reconsider the load rating of this bridge. Again, it’s worth noting that these forces are peak forces determined from a linear-elastic finite element model. A non-linear analysis may find that with


some local cracking and crushing, the peak forces are reduced dramatically.

As the bearing walls do not come into contact with the outer shells of the piers during normal loading conditions, the outer shells were not modelled for this analysis. Inclusion of the pier shells could have skewed the results for the bearing walls by creating a further load path or stiffening effect on the section. However, some HB load cases could cause the piers, in theory, to deflect enough that some of the load is passed via the stops into the pier shells. This would reduce the force in the bearing walls as force is transferred to the pier shells.

7.1.4 Remaining Elements

The remaining structural elements experience very little force increase from the applied settlements. This is in line with the theory that the relatively flexible bearing wall elements accommodate much of the induced settlement.

The only area remotely close to the 2.5% utilisation limit was the deck under shear. It is worth noting that, due to lack of information, the lightest reinforced longitudinal section of deck was used for this analysis. The reasons for this are that it would give a conservative result. Using a densely reinforced section would have significantly reduced the utilisation result.

The values of volume loss which have been assessed are at the higher end of the probable values scale and are deemed conservative. It may be possible to achieve a volume loss of less than 1.0% during construction. This has been shown to be achievable in similar construction projects in London.

With the exception of the pier bearing walls, it can be seen that the effects of the proposed tunnel on Waterloo Bridge are not significant and is within a 2.5% ULS threshold. Under normal working HA loading, utilisations of the bearing wall corners were found to be up to 116% ULS bending capacity. These peak forces may indicate that some local cracking and/or crushing may be occurring in these locations.

Peak forces were used for the structure sections to give a conservative assessment. With a more refined non-linear analysis these peak forces may reduce. The tops of the bearing walls were found to be above their ULS capacity, with a utilisation of the bearing wall corners of 130% ULS bending capacity. No weight restrictions are currently in place on Waterloo Bridge. In light of the assessment findings the asset owner may wish to introduce a weight restriction on Waterloo Bridge limiting HB vehicles.

What is shown by the analysis is that the settlement effect of the bearing walls has a slight relieving effect on the bearing wall section.

7.1.5 Bow Wave Results

Temporary ‘bow wave’ effects have been analysed using the 3D model as outlined in section 4.4. Using the conservative 1.7% soil volume loss, all checked members showed a stress increase of less than 2.5% utilisation at ULS, as summarised in Table 9. This is due to the relatively minor


1.1mm differential displacement across the pier, when proportioned from the tunnel centre line.

The results summarised in Table 10 for the half joint show the minimal effect the bow wave settlement would have on this section. The stress rise due to the settlement is many times less than what would be seen in this section through normal working loads.

7.2 Utilities

Based on the assumptions made in 5.5, it is envisaged that the calculated vertical deflections, a maximum of 3.7mm between pier 2 and pier 3 for a Volume Loss VL=1.7%, will have no detrimental effect on the relatively flexible services embedded in the concrete deck.

With regard to the rainwater drainage, the transverse cross-fall on the deck provides water shedding to the kerb line of the deck. The predicted additional deflections, resulting from envisaged settlements, are not expected to be sufficient to impact the deck drainage over the river spans. This is based on the calculated small differential settlement both longitudinally and transversely.


8 Conclusions & Recommendations


With the exception of the pier bearing walls, the stress increase identified in the settlement assessment is less than what would be considered to be significant. As the pier bearing walls exhibited a marked increase in applied force, as a result of the settlement only loadcase, these elements were checked with regard to live loading. It was found that under a number of live load combinations areas of the bearing wall were beyond their ULS capacity. Combinations where live loading was combined with settlement effects showed a reduction of working load in the bearing walls, this indicates the slight settlement and rotation, as a result of the tunnelling construction, would be load-relieving.

While no stress relieving recommendations are felt necessary. The result of the assessment indicates a weight restriction limiting HB vehicles from the bridge may be beneficial, or require further investigation by the asset owner.

It is worth noting that, these utilisations are taken from peak force values from a linear elastic finite element model. Further detailed non-linear analysis of the bearing walls may show a reduced level of working load in the structure. However, for the purposes of the settlement assessment it is felt that the current model covers the requirements of assessing the structure with regards to tunnel induced settlement. The bridge owner may feel that it is necessary to undertake a full live loading assessment of the structure to determine a more detailed working stress of elements indicated to be at risk.

It is recommended that a settlement monitoring program be implemented whilst tunnelling works are undertaken, to ensure that predicted settlements of the structure relate to actual settlements of the structure during construction. Pre and post construction inspections should also be undertaken to record any defects as a result of the tunnelling works.

8.2 Utilities

There are no recommendations for the utilities on Waterloo Bridge.

Assessment Report 16/09/2013

APPENDIX 1 – Approval in Principle

Document No. 314-EA-TPI-BR015-000001-AF


APPENDIX 2 – Inspection Report

Document No. 314-RI-TPI-BR015-000001-AC


APPENDIX 3 – Predicted Settlement Troughs

Graphs are provided for vertical and horizontal settlement, as well as, ground slope and tensile strain at 1.0% and 1.7% volume loss. Each of the above cases will be provided at base of the foundation level and at ground surface level. Each longitudinal settlement case begins with a layout plot which depicts the depth to tunnel centre line and its location relative to the foundation footprint. If the tunnel is located at mid-span, then only a single foundation will be shown for clarity. The second graph shows settlement and horizontal movement from the tunnel centre line. This graph can be used to read off horizontal and vertical movements at various distances from the tunnel axis. The third graph depicts the slope of the settlement trough and the horizontal tensile strain, which can be read off at various distances from the tunnel central axis. The final graph shows a detailed view of the vertical settlement and values at points of interest, such as edges of foundation. The following longitudinal settlement cases are provided in this report;

1. Foundation Ground Level at 1.0% Volume Loss

2. Foundation Base of Foundation Level at 1.0% Volume Loss

3. Foundation Ground Level at 1.7% Volume Loss

4. Foundation Base of Foundation Level at 1.7% Volume Loss

Bow wave (transverse) settlements are provided at 1.0% and 1.7% soil volume loss and calculated

when the tunnel is at the centre of the foundation and again when the tunnel reaches the back face of

the foundation.

Each bow wave settlement case begins with a layout plot depicting the location of the tunnel in relation

to the foundation. The layout plot is then followed by the settlement plot.

The following bow wave (transverse) settlement cases are provided in this report;

5. Tunnel at Centre of Foundation at 1.0% Volume Loss

6. Tunnel at Centre of Foundation at 1.7% Volume Loss

7. Tunnel at rear face of Foundation at 1.0% Volume Loss

8. Tunnel at rear face of Foundation at 1.7% Volume Loss


APPENDIX 4 – Assessment Calculations

Calculations are included for a volume loss of 1.7% and 1.0% for both longitudinal settlement and transverse settlement effects, as well as, Dead Load, Super-Imposed Dead load and Live Load combinations.

Pages 1-60: Longitudinal Settlement Calculations

Sections 1. Introduction 2. Modelling 3. Material Strengths 4. Factors 5. Dead Load of Span 6. Permanent Loads 7. Variable Loads 8. Piers 9. Abutments 10. Deck 11. Box Girder Flanges 12. Box Girder Webs

Pages 60-109: Bow Wave (Transverse) Settlement Calculations

Sections 1. Introduction 2. Modelling 3. Bow Wave 4. Deck Slab 5. Box Girder Flanges 6. Box Girder Webs 7. Half Joint

314-RI-TPI-BR015-000001 | AB |


Inspection for Assessment Report Waterloo Bridge Structure No. BR015

THIS REPORT INCLUDING THE DRAWINGS AND OTHER SUPPORTING DOCUMENTATION IS PROVIDED FOR THE PURPOSE OF IDENTIFYING AND AGREEING THE LIKELY EFFECTS OF THE CONSTRUCTION OF THE THAMES TUNNEL ON THE ASSETS AND INFRASTRUCTURE OF THE PARTY IN RECEIPT OF THIS REPORT AND FOR THE PURPOSE OF SECURING APPROVAL IN PRINCIPLE TO THE DESIGN OF THE THAMES TUNNEL. THE REPORT IS CONFIDENTIAL TO THAMES WATER AND THE INTENDED RECIPIENT AND THEIR CONSULTANTS [APPOINTED WITH THE AGREEMENT OF THAMES WATER]. THE REPORT SHALL NOT BE PROVIDED TO ANY THIRD PARTY WITHOUT THE EXPRESS WRITTEN PERMISSION OF THAMES WATER UTLIITIES LIMITED.

Inspection for Assessment Report 28/11/2011


Inspection for Assessment Report

Name Data

Document no 314-RI-TPI-BR015-000001 | AB

Status APP/PUB

Document type Report

WBS DE.03.3P

Authors Ben Burney

Keywords Waterloo, Bridge, Assessment, Inspection Report

Contents amendment record

This document has been issued and amended as follows:

Revision Date Issued for/Revision details Revised by

AA 16/11/2011 First Issue -

AB 28/11/2011 Second Issue / Sect. 5.3 JDB

Required approvals

28/11/2011

George Lawlor – Project Manager

Date

314-RI-TPI-BR015-000001 | AB

Inspection for Assessment Report Page 1 28/11/2011



List of contents

Page number

1 Summary ........................................................................................................... 2

2 Introduction ...................................................................................................... 3

2.1 Purpose of Inspection .............................................................................. 3

2.2 General Inspection Methodology ............................................................. 3

2.3 Inspection Details .................................................................................... 3

3 Description of Structure .................................................................................. 5

3.1 Location Plan ........................................................................................... 5

3.2 Superstructure ......................................................................................... 6

3.3 Substructure ............................................................................................ 7

3.4 Spans ...................................................................................................... 7

4 Inspection and Maintenance History .............................................................. 8

4.1 Maintenance History ................................................................................ 8

4.2 Inspection History .................................................................................... 8

5 General Observations ...................................................................................... 9

5.1 Substructure ............................................................................................ 9

5.2 Superstructure ....................................................................................... 11

5.3 Bearings ................................................................................................ 15

5.4 Parapets ................................................................................................ 15

5.5 Services ................................................................................................. 16

5.6 Joints ..................................................................................................... 16

5.7 Surfacing ............................................................................................... 17

5.8 Drainage ................................................................................................ 19

5.9 Ancillary ................................................................................................. 20

6 Conclusions .................................................................................................... 22

7 Recommendations ......................................................................................... 22

314-RI-TPI-BR015-000001 | AB


1 Summary

AECOM has been commissioned by the Thames Tunnel to carry out an Inspection for Assessment of Waterloo Bridge for Sub-package 3b of the Detailed Bridge Assessment contract for the Thames Tunnel project.

The aim of the project is to identify any structural or serviceability implications that may result from proposed tunnelling works in the vicinity of the existing infrastructure.

Waterloo Bridge is a five span, reinforced concrete, box girder bridge. Originally opened to the public in 1942 the structure spans over the Thames between the Southbank and Victoria Embankment.

The inspection was conducted on the 27th of October 2011 by AECOM Ltd. The inspection comprised of a visual survey from bridge deck level, embankment footways and a boat, during daytime hours and in accordance with the approved method statement (Doc. No. 314-PE-TPI-BR015-000001-AA).

Generally the bridge was in a fair condition with some signs of deterioration. The main structural elements were observed to have minor cracking and some spalling with spots of rust staining throughout. The spalling observed on the cross beams was generally located on the beam soffits adjacent to the webs of the main box girders. The area of the soffit around the drop-in span half joint is heavily stained and looks to be in poor condition. The connections between the bearing walls and the main box girders appear to be in good condition. There is a minor silt build up and flooding around the movement joints in the bridge deck. This does not appear to be impacting on their ability to permit movement. The carriageway was observed to be in very good general condition, apart from a couple of areas of break-up. The pedestrian footways were found to be in a poor condition with large areas of isolated cracking to the paving slabs. Although minor defects are widespread throughout the structure they are not deemed to have a significant effect on the structural capacity of the members.

Based on the inspection it is recommended that a condition factor of 1.0 is applied to all structural members in the assessment of Waterloo Bridge (Doc. No. 314-RG-TPI-BR015-000001).

314-RI-TPI-BR015-000001 | AB


2 Introduction

2.1 Purpose of Inspection

AECOM has been commissioned by Thames Tunnel to carry out an Inspection for Assessment of Waterloo Bridge. This forms a part of the Sub-package 3b of the Detailed Bridge Assessment contract for impact assessment of proposed tunnelling works for the Thames Tunnel project.

The main objective of the project is to identify any structural or serviceability implications that may result from proposed tunnelling works in the vicinity of the existing infrastructure. The inspection for assessment has been focused specifically at the elements which could potentially be affected by the proposed Thames Tunnel construction.

2.2 General Inspection Methodology

Initial assessment results identified parts of the structure which could potentially be affected by the tunnelling work. An initial inspection of all the visible parts of the structure was performed from land before a more focused Inspection for assessment was undertaken from the river.

Piers 1 and 2, with pier 1 being the most northern pier, have been identified as being within the influence zone of the greenfield settlement trough caused by the proposed tunnelling works, together with adjacent spans, i.e. River Spans 1, 2, and 3.

The inspection has been focused on the connections between the pier bearing walls and the main box girders, although all visible elements were inspected. The inspection was visual only and took place from the bridge deck level, embankment footways and a boat, during daytime hours.

All parts of the structure that are visible from the deck, embankments and the boat were inspected. All major defects were recorded and photographed. Procedures were in accordance with the method statement for the inspection for assessment of Bow Common Lane Bridge (Doc. No. 314-PE-TPI-BR015-000001-AC) and followed the relevant sections of BD62/07 and BD63/07.

2.3 Inspection Details

Inspected by: AECOM Ltd

G Lawlor, B Burney, J Boam.

Equipment used: Digital camera

Date of Inspection: 27th October 2011

Weather Conditions: Overcast with light rain showers.

Access: By footways on deck, Southbank and Victoria Embankment.

314-RI-TPI-BR015-000001 | AB


By river boat from Butlers Wharf (downstream).

Areas not inspected: Foundations, piers below the water line, internal areas of box girders, bearings at half joints.

314-RI-TPI-BR015-000001 | AB


3 Description of Structure

Waterloo Bridge is a five span, reinforced concrete, box girder bridge. Originally opened to the public in 1942 the structure spans over the Thames between the Southbank and Victoria Embankment. The structure is located on Ordnance Survey grid reference TQ307805.

Photograph 1 General view of the structure

3.1 Location Plan

Figure 1 Location plan of Waterloo Bridge

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3.2 Superstructure

Originally constructed between 1937 and 1942 Waterloo Bridge is a 427m long, 25.3m wide, five span reinforced concrete cantilever box girder bridge. The bridge is supported on abutments at the north and south, and four river piers. The Grade II listed structure carries the A301 over the River Thames and Victoria Embankment (A3211). Spans and piers are numbered from the north end of the structure.

The deck is made up of two box sections that consist of three cells. Each box is 7.62m wide and varies in height from 2.29m at the midspan to 6.71m at the abutments and 7.54m at the piers. There are diaphragms in the box girders spaced at 3.85m centres.

Spanning transversely between the two boxes are 10.06m long cellular reinforced concrete (RC) beams that support RC slabs. The cellular beams are 1.98m deep and coincide with the diaphragm spacing. The RC slabs have a maximum thickness of 380mm.

The central 28.6m of span 3 is a drop-in span. The northern section of the bridge spans from the north abutment over pier 1 and pier 2. This section also cantilevers north of the north abutment and south of pier 2 to the drop-in span in span 3. The southern section of the bridge spans from the south abutment over pier 4 and pier 3. This section also cantilevers south of the south abutment and north of pier 3 to the drop-in span in span 3. In both sections the cantilever beyond the abutment is 23.4m long and the cantilever in span 3 is 23.9m. The end of the abutment cantilevers are counterbalanced with cast iron kentledge weighing 570 tons in total. At the end of the centre span cantilevers 63 tons of cast iron kentledge is positioned.

The sides of the deck are faced with Portland Stone panels.

The carriageway has two lanes in either direction separated by concrete kerb stones and an artificial stone central reservation. The footways are separated from the running lanes by granite kerbstones. Each carriageway is 8.1m wide, the central reservation is 1.5m wide and the footways are 3.3m wide.

The bridge deck is continuous over the piers and abutments with a simply supported deck section in span 3. A small approach slab is cast between the ends of the abutment cantilevers and the approach structures. The approach slab is connected to the abutment cantilevers with a knuckle joint. There are expansion joints between the approach slabs and the abutments cantilevers. There are longitudinal expansion joints along the east and west sides of both the abutment cantilevers.

Two expansion joints are also located in span 3 on either side of the simply supported section of deck which is supported on rocker bearings in the half joints. These bearings can accommodate a movement of 152mm.

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3.3 Substructure

The piers are of reinforced concrete construction and consist of a bearing wall surrounded by an RC shell with a total width of 32.39m, height of approximately 13.5m and a maximum thickness of 4.27m. The bearing walls are 686mm thick and are approximately 13.5m high. The shell wraps around the piers and is stiffened with vertical and horizontal ribs. The ribs on either side of the bearing walls are only connected with steel ties that pass through the bearing walls. The voids between the bearing wall and shell ribs allow water to fill the inside of the pier to counteract the hydrostatic pressure on the outside of the shell. The bearing walls and shells are connected cellular RC bases 2.44m high, 32.39m wide and 4.27m thick. The piers are clad with granite on the lower section and clad with Portland stone on the upper.

The abutments are of similar construction to the piers but have a height of approximately 11.85m and a maximum thickness of 3.80m. Between the two box girders, the pier is 8.1m high. The bearing wall of the abutments is 572mm thick. The bearing wall and shell sit on an RC cellular base similar to the piers.

The river piers are founded on 1.83m high, 35.66m wide and 8.23m thick mass concrete caissons. The steel sheet piling used to construct the caissons has been left in place.

Both the abutments are founded on similar foundations which are 7.77m thick. As with the piers, the steel sheet piling has been left in position.

3.4 Spans

Waterloo Bridge has 5No. of spans: The North span crosses both Victoria Embankment and a section of the River Thames While the South span crosses the South Bank pedestrian footway and a section of the River Thames. The remaining 3No. Spans cross the river only. Spans will be referred in the inspection report as follows:

Span 1 L1 = 73.184m

Span 2 L2 = 76.302m

Span 3 L3 = 76.302m

Span 4 L4 = 76.302m

Span 5 L5 = 73.184m

The abutment cantilevers both have a span of 23.438m.

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4 Inspection and Maintenance History

4.1 Maintenance History

The maintenance history of Waterloo Bridge is unknown.

4.2 Inspection History

The full inspection history for Waterloo Bridge is not known. From the information provided by the City of Westminster, the following inspections have been undertaken;

- Principal inspection May 1989

- Principal inspection January 1996

- General inspection March 2003

- Principal inspection April 2006

- Principal inspection January 2007

- General inspection September 2008

From the information provided the following ancillary structure inspections have been undertaken;

- Principal inspection of the south-east slip road May 2005

- Principal inspection of the east and west subways May 2005

- Principal inspection of Waterloo Bridge south footbridge January 2007

- Principal inspection of south retaining wall September 2007

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5 General Observations

5.1 Substructure

The visible areas of the piers were found to be in a good general condition. Organic growth was found around the waterline. Some of the inspection covers on the north and south face of the piers were found to be missing or loose [photograph 2]. There was water staining to the masonry cladding below the missing inspection covers. A number of areas of light spalling and surface wear were found around the edges of the masonry cladding on the piers. These may have been caused due to weathering or ship impact in the past [photograph 3].

Photograph 2 Missing inspection cover on pier and staining on masonry cladding

Photograph 3 Typical pier weathering and face loss of masonry cladding

314-RI-TPI-BR015-000001 | AB


A number of areas of graffiti were found around pier 4During low tide pier 4 is accessible by the public from the Southbank

Photograph 4 Graffiti around pier 4

The visible areas of the abutments were found to be in a good condition. However, commercial enterprises residing abutments meant that a large extent of the abutments could not be inspected [photograph 5]

Photograph 5 Enterprises adjacent to south abutment

Page 10

A number of areas of graffiti were found around pier 4pier 4 is accessible by the public from the Southbank

Graffiti around pier 4

The visible areas of the abutments were found to be in a good condition. However, commercial enterprises residing adjacent to and withinabutments meant that a large extent of the abutments could not be

otograph 5].

Enterprises adjacent to south abutment

28/11/2011

A number of areas of graffiti were found around pier 4 [photograph 4]. pier 4 is accessible by the public from the Southbank.

The visible areas of the abutments were found to be in a good condition. adjacent to and within the

abutments meant that a large extent of the abutments could not be

314-RI-TPI-BR015-000001 | AB


5.2 Superstructure

The external webs of the box girders are covered in cladding and therefore could not be inspected. The cladding appears to be in good condition. The soffits of both box girders have some large areas of water staining and light cracking throughout. There are also small spots of minor rust staining from the reinforcement throughout box girders [photograph 6].

Photograph 6 Water staining, rust staining and cracking on box girder soffit

There are a number of spalled areas of the internal webs of the box girders with exposed and corroding reinforcement. Large areas of minor cracking to the internal webs were also noted [photograph 7].

Photograph 7 Spalling and cracking on internal web of box girder

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The soffits of the main box girders were heavily water and rust stained in span 3 either side of the drop-in span [photograph 8]. This is likely to be caused by the apparent permeability of the half joints. The profile of the main box girders then causes the staining to run down from the half joints to the piers.

Photograph 8 Staining to soffit of main box girders at drop in span half joint

314-RI-TPI-BR015-000001 | AB


A number of patches of graffiti were located on the internal webs of the box girders around pier 4 [photograph 9]. This pier is accessible by the public at low tide.

Photograph 9 Graffiti on the internal webs of the box girders above pier 4

A number of areas of spalling were observed on the cross girders in all spans. The spalling was generally on the soffits of the cross beams adjacent to the internal webs of the main box girders. Accompanying the spalling was exposed, rusted and corroding reinforcement [photograph 10].

Photograph 10 Typical spalling and exposed, corroding reinforcement on cross girder

314-RI-TPI-BR015-000001 | AB


There was also deck soffit. The deck soffit was observed to have staining and minor fractures

Photograph 11 Typical rust staining and cracking to deck soffit

A number of small areas of minor spallingreinforcement were also found in the deck soffit

Photograph 12 Spalling of deck soffit with e

Page 14

minor cracking throughout the cross members and the The deck soffit was observed to have many

staining and minor fractures [photograph 11].

Typical rust staining and cracking to deck soffit and cross girders

A number of small areas of minor spalling with reinforcement were also found in the deck soffit [photograph 1

Spalling of deck soffit with exposed and corroding reinforcement

28/11/2011

throughout the cross members and the many areas of rust

and cross girders

exposing steel [photograph 12].

xposed and corroding reinforcement

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5.3 Bearings

The bearings in the half joints within span 3 could not be inspected. As the movement joints are functioning well, however, the bearings would appear to be in working order.

5.4 Parapets

The steel parapets adjacent to the east and west footways appear to be in very good condition and showing no signs of distress. There is evidence that the masonry parapet foundry blocks have cracked and subsequently been repaired [photograph 13]. The repairs have no defects.

Photograph 13 Typical repairs to cracking in masonry parapet foundry blocks

A number of areas of graffiti were found on the west parapet founding blocks [photograph 14].

Photograph 14 Graffiti to masonry parapet foundry blocks

314-RI-TPI-BR015-000001 | AB


The bottoms of the posts of the steel parapets on top of the piers were showing signs of heavy rusting [photograph 15].

Photograph 15 Rusting to bottom of post of steel parapet on top of piers

5.5 Services

From achieve information there appears to be both BT telecoms and fibre optic cables passing over the structure. As these services were either buried in the carriageway or inside the box girders they could not be inspected.

5.6 Joints

There is some isolated damaged concrete to the soffit of the main box at the location of one of the half joints [photograph 16]. This damage does appear to have been repaired. The repair is in good condition

Photograph 16 Repair to damaged concrete around drop-in span half joint

314-RI-TPI-BR015-000001 | AB


From deck level the movement joints at the ends of the structure and over the drop-in span appear to be in a fair condition. There is a build up of debris in the movement joints that is inhibiting the drainage and causing minor flooding [photograph 17]. This build up of debris is generally more apparent on the west carriageway.

Photograph 17 Debris in expansion joint at north end of structure

5.7 Surfacing

The surfacing adjacent to all the movement joints has settled slightly and is cracked [photograph 18].

Photograph 18 Settlement and cracking of carriageway around movement joint

314-RI-TPI-BR015-000001 | AB


The remainder of the carriageway is largely in a good general condition. However, there are two large defects in the carriageway. A large piece of carriageway has come loose adjacent to the west kerb at the north end of the structure, at around mid-span of span 1, this is in the middle of a previous patch repair [photograph 19].

Photograph 19 Heavily cracked and loose lump of surfacing in west carriageway

Part of the carriageway is cracked in a rectangular pattern adjacent to the south of the drop-in span on the east side of the structure [photograph 20]. The east side of the cracking is developing into a large pot hole.

Photograph 20 Rectangular cracking and pot hole located in east carriageway

314-RI-TPI-BR015-000001 | AB


The east and west footways are in poor condition with large areas of cracked paving slabs [photograph 21]. There does not appear to be a pattern to the cracking.

Photograph 21 Typical cracking to footway paving slabs

5.8 Drainage

A number of drains along the kerb lines of the structure appeared to be filled with debris [photograph 22]. The water staining below the deck drainage outlets at the top of the pier bearing wall would suggest that the drainage system is still functioning to some extent.

Photograph 22 Build up of debris to carriageway drains

314-RI-TPI-BR015-000001 | AB


Many of the expansion joints were flooded near the kerbs of the carriageway caused by the build up of debris [photograph 17]. The staining to the soffit of the main box girders adjacent to the drop-in span also suggests that the drainage is not functioning properly [photograph 8].

5.9 Ancillary

A loose bolt was found in the metallic flashing over the drop-in span expansion joint at the north-west side of the structure in the footway [photograph 23].

Photograph 23 Build up of debris to carriageway drains

The access stairs at the south-west and north-east end of the structure have cracking to the stair tiles [photograph 24].

Photograph 24 Cracking to access stairs at north-east of structure

314-RI-TPI-BR015-000001 | AB


A number or areas of graffiti were found around the north-east access stairs [photograph 25].

Photograph 25 Graffiti to access stairs at north-east of structure

The access ladders and platforms to the top of the piers were rusted [photograph 26].

Photograph 26 Rusting to pier access ladders

314-RI-TPI-BR015-000001 | AB


6 Conclusions

Generally the bridge was in a fair condition with some signs of deterioration.

The main structural elements were observed to have similar faults; minor cracking, localised spalling and mild corrosion to the exposed reinforcement. Spalling of the structural elements does not appear to follow any particular pattern that could be attributed to a general weakness of the structure. The spalling is most likely caused by poor compaction of the concrete during construction. This is supported by the more regular locations of spall to the soffits of the cross girders. In these locations it would be difficult to ensure the concrete mix and compaction was adequate due to the shape of the beam and amount of reinforcement. The spalling is very localised and is unlikely to have an impact on the overall resistance of the members at present.

The rust staining spots on the soffit of the deck and main box girders suggests that water is percolating through the deck. In future this may result in some further localised spalling of the soffits of these elements as the reinforcing bar corrodes. At present, however, it is only a minor defect.

The staining on the soffits of the main box girders adjacent to the half joints is a clear indication of the joints’ permeability. The rust staining may be from reinforcement near the joint face or the steel rocker bearing at the joint. Although the staining is quite heavy and suggests some corrosion, the location of any such defect is unlikely to be critical. Despite the build up of debris in the movement joints it would appear the joint is still able to function properly and permit movement.

Although the majority of the pier bearing wall was not visible, the connections between the bearing walls and the main box girders were in good condition.

The pedestrian footways were found to be in a poor condition with large areas of isolated cracking to the paving slabs. These cracks didn’t follow any particular pattern but occurred regularly along each footway. The carriageway was observed to be in very good general condition, apart from a couple of areas of break-up. However, these areas of break-up have only occurred at places where carriageway maintenance has been undertaken and not representative of the general carriageway condition.

7 Recommendations

Based on the condition of the structural members inspected a condition factor of 1.0 will be applied to all structural members in the assessment of Waterloo Bridge (Doc. No. 314-RG-TPI-BR015-000001).

THAMES TUNNEL DETAILED BRIDGE ASSESSMENTS

Waterloo Bridge

Structure Ref No: BR015

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APPROVAL IN PRINCIPLE (Assessment AIP)

Name of Project Thames Tunnel Detailed

Bridge Assessments

Name of Bridge or Structure Waterloo Bridge

Structure Ref No. BR015

1. HIGHWAY DETAILS

1.1 Type of highway The bridge supports the A301 a dual two-lane highway with a cycle lane and footpath on either side.

1.2 Permitted traffic speed 30m.p.h

1.3 Existing weight restriction

None

2. SITE DETAILS

2.1 Obstacles crossed

Waterloo Bridge crosses over the Victoria Embankment and the River Thames adjacent to Somerset House on the north bank and The National Theatre on the south bank.

3. EXISTING STRUCTURE

3.1 Description of structure

Originally constructed between 1937 and 1942, the Grade II listed Waterloo Bridge is a 423m long, 25.3m wide, seven span reinforced concrete cantilever box girder bridge. The bridge is supported on abutments at the north and south, four river piers and two shore piers. The Grade II listed structure carries the A301 over the River Thames and Victoria Embankment (A3211). Spans and piers are numbered from the north end of the structure. The deck is made up of two box sections that consist of three cells. Each box is 7.62m wide and varies in height from 2.29m at the mid-span to 6.71m at the shore piers and 7.54m at the river piers. There are diaphragms in the box girders spaced at 3.85m centres. Spanning transversely between the two boxes are 10.06m long cellular reinforced concrete (RC) beams that support RC slabs. The cellular beams are 1.98m deep and coincide with the spacing of the diaphragms. The RC slabs have a maximum thickness of 380mm.


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Figure 1 Drop-in Span Half Joint

The central 28.6m of span 4 is a drop-in span. The drop-in deck section is articulated from the continuous deck by expansion joints located in the half joint. The expansion joints are of the single segmental roller-bearing type. The bridge is designed for a total change in length of 152mm distributed equally between the 4 expansion joints i.e. abutments and drop in span half joints. The main roller-bearings are limited in width to the thickness of the deck box webs. Medium high-tensile steel has been used, with a diameter of 1016mm, for the roller-bearings. The principal compression component force at the drop-in span half joint is transferred from the bearing billets by means of 4No. mild steel shear plates. The main tensile component at the joint is resisted by medium high-tensile post-tensioned bars. See Figure 1 Below. The bars are contained within steel tubes and fitted with projected end connections. After the surrounding concrete had hardened steam was passed through the tubes, the thermal expansion was taken up by turning the turnbuckles so that upon cooling the bars would


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be at the required stress of 207 Newton’s per millimetre square. After stressing, the bars were grouted up in their tubes. Secondary roller-bearings in the deck and box girder bottom flange are provided to limit transverse deflections and maintain the vertical rollers in a stable position by transmitting torsion forces from torsional deflection across the joint, allowing the whole span to act torsionally as if monolithic. The northern section of the bridge spans from the north abutment monolithically with pier 1, pier 2 and pier 3. This section also cantilevers south of pier 3 to the drop-in span, in span 4. The southern section of the bridge spans from the south abutment monolithically with pier 6, pier 5 and pier 4. This section also cantilevers north of pier 4 to the drop-in span, in span 4. The shore cantilevers beyond pier 1 and pier 6 are 23.4m long and the cantilevers in span 4 are 23.9m. The end of the abutment cantilevers are counterbalanced with cast iron kentledge weighing 570 tons in total. The connection to the abutments is achieved by a short RC slab connected to a steel knuckle joint on the end of the bridge deck and to recently installed elastomeric bearings on the abutment shelves on the approach structures. At the end of the centre span cantilevers 63 tons of cast iron kentledge is positioned. Medium high-tensile steel pre-stressed bars are located in the vicinity of the shore cantilevers above the bearing walls, these are stressed in the same way as the span 4 half joint bars. The pre-stressing is provided to control local high shear stresses. The sides of the deck are faced with Portland Stone panels. The piers are of reinforced concrete construction and consist of a bearing wall, which is monolithic with the deck box-sections, surrounded by an RC shell, with a total width of 32.39m, height of approximately 13.5m and a maximum thickness of 4.27m. The bearing walls are 686mm thick and are approximately 13.5m high. The flexibility of the bearing walls, being monolithic with the deck and the foundations, act horizontally as spring supports. As designed these are balanced between the north and south sections of the bridge to induce equal movements at each joint. The shell wraps around the piers and is stiffened with vertical and horizontal ribs. The function of the pier shell is to withstand impact forces, act as a


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permanent coffer dam to the bearing wall, should they need maintenance, and restrict extreme movements of the bridge superstructure via stone pads located at the top of the shell. The ribs on either side of the bearing walls are connected with steel ties that pass through the bearing walls. The voids between the bearing wall and shell ribs allow water to fill the inside of the pier to counteract the hydrostatic pressure on the outside of the shell. The bearing walls and shells are connected to cellular RC bases 2.44m high, 32.39m wide and 4.27m thick. The piers are clad with granite on the lower section and clad with Portland stone on the upper. The shore piers are of similar construction to the river piers but have a height of approximately 11.85m and a maximum thickness of 3.80m. Between the two box girders, the pier is 8.1m high. The bearing wall of the shore piers is 572mm thick. The bearing wall and shell sit on an RC cellular base similar to the river piers. The piers are enclosed within a Portland stone clad enclosure to the north and within the National Film Theatre to the south. The carriageway has two lanes in either direction separated by concrete kerb stones and an artificial stone central reservation. The footways are separated from the running lanes by granite kerbstones. Each carriageway is 8.1m wide, the central reservation is 1.5m wide and the footways are 3.3m wide.

3.2 Structural type The main section of the deck is formed of two varying depth longitudinal spine beams, one at each side of the width of the deck. Each spine is formed of a three cell longitudinal box girder. The spine beams are connected transversely by reinforced concrete cellular cross girders which support the deck slab.

The substructure is formed of reinforced concrete piers and abutments consisting of bearing walls, which are monolithic with the deck spine beams, and shells supported on mass concrete foundations.

3.3 Foundation type The river piers are founded on 1.83m high, 35.66m wide and 8.23m thick mass concrete caissons. The steel sheet piling used to construct the caissons has been left in place. Both of the shore piers are founded on similar


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foundations that are 7.77m thick. As with the river piers, the steel sheet piling has been left in position. Each abutment consists of a reinforced concrete capping beam fixed to the existing approach structures.

3.4 Span arrangements Waterloo Bridge has 7No. of spans: The North span 1 crosses the Buddha Bar while span 2 crosses both Victoria Embankment and a section of the River Thames. While the South span 7 provides a vault which now houses the British Film Institute, span 6 crosses the South Bank pedestrian footway and a section of the River Thames. The remaining 3No. Spans cross the river only. Spans will be referred in the assessment process as follows: North Shore Cantilever L1 = 23.7m North Bank Span L2 = 73.184m River Span 3 L3 = 76.302m River Span 4 L4 = 76.302m River Span 5 L5 = 76.302m South Bank Span L6 = 73.184m South Shore Cantilever L7 = 23.7m

3.5 Articulation arrangements Figure 2 Diagram of articulation

The bridge deck is monolithic with the piers, with a drop-in deck section in span 4. The drop-in deck section is articulated from the continuous deck by expansion joints located in the half joint. A steel knuckle joint on the end of the bridge deck connects to a 4m, length, cast approach slab which connects, via recently installed elastomeric bearings, to the abutment shelves on the approach structures. The approach slab is connected to the shore cantilevers via an elastomeric joint.

There are expansion joints between the approach slabs and the abutment cantilevers. Also, longitudinal expansion joints are located along the east and west sides of both of the shore cantilevers. Two expansion joints are also


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located in span 4 on either side of the simply supported section of deck; see section 3.1 for a detailed description. Longitudinal movements are accommodated by single segmental roller-type bearings, elastomeric joints and flexure of the monolithic bearing walls. The deck is articulated by knuckle joints in the half joints in span 4 and elastomeric joints at the abutments, as well, as rotations allowed for by flexure of the bearing walls.

3.6 Road restraint system type The parapets are approximately 1.2m high and consist of metallic railings founded on a Portland Stone base and cornice. The parapets do not comply with the requirements for vehicle restraint systems in accordance with TD 19/06 and the associated standards.

3.7 Proposed arrangements for Inspection for Assessment

A focused Inspection for Assessment will be undertaken once the elements of structure, potentially affected by the tunnelling work are identified. The inspection will be visual only and will take place from the bridge deck level and from the river during daytime hours, avoiding peak traffic times.

Piers 2 and 3, with pier 1 being the most northern pier, have been identified as being within the influence zone of the greenfield settlement trough caused by the proposed tunnelling works, together with adjacent spans, i.e. River Spans 2, 3, and 4.

The inspection will be focused on the connections between the pier bearing walls and the main box girders, although all visible elements will be inspected. The inspection is visual only and will take place from the bridge deck level, embankment footways and a boat, during daytime hours.

All parts of the structure that are visible from the deck, embankments and the boat are to be inspected. All major defects will be recorded and photographed. Full procedures will be outlined and in accordance with the method statement for the inspection for assessment of Waterloo Bridge. Waterloo Bridge will be inspected and City of Westminster (CoW) will be notified of the dates, once such are confirmed. The method statement for undertaking the visual inspection work and risk assessment will be forwarded to CoW, for information only.


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At this stage of the planning process of the Thames Tunnel Project an internal inspection of the spine beams will not be undertaken. However, should future planning proposals be accepted an internal inspection of the spine beams will be undertaken to confirm the assumptions of condition made in the assessment of the structure. At this stage CoW will be notified and a method statement will be prepared and agreed prior to commencement of work.

3.7.1 Traffic management Traffic management will be required to undertake the internal inspection of the spine beams. This detail will be produced in full within a separate, more focused, method statement and risk assessment when required.

3.7.2 Access Access by foot shall be obtained from the highways above and at the north and south river banks below.

The bridge soffit shall be viewed from a boat on the water.

3.7.3 Intrusive or further investigations proposed

None

3.8 Materials strengths assumed and basis of assumptions

Concrete: 35N/mm2

Steel bars: 250N/mm2

(New Waterloo Bridge, Buckton and Cuerel On, archive doc)

Pre-stress bars: 230N/mm2

(Assumed Pre 1955 steel; BD21/01 CL4.3)

3.9 Risks and hazards considered Risks to the assessment include defects hidden from view during the inspection, which could have a detrimental effect on the structures strength, and unknown structural details which cannot be obtained due to a lack of archive information. Hazards will be outlined for the inspection process within the relevant method statements.

3.10 Year of Construction Waterloo Bridge was opened to the public in 1942.

3.11 Reason for Assessment The proposed Thames Tunnel will pass underneath the structure potentially causing settlement beneath the foundations of the bridge. See appendix C for a diagram of the tunnel path and location in relation to the structure. The assessment will quantify the impact of the proposed tunnel on the existing


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bridge.

3.12 Part of structure to be assessed All longitudinal, transverse and vertical elements affected by the proposed tunnel will be assessed. The proposed tunnel passes close to the centre line of span 3, potentially causing piers 2 and 3 to settle. Consequently, for the long term case, the area to be considered will be the first 4 spans, from the drop in section in span 4, to the north end of the bridge at the abutment joint. The transverse effect of the passage of the tunnelling machine on the piers and deck members will also be investigated, assuming tunnelling stops at one side of a pier to cause the greatest differential settlement across the bridge. It is expected that the Bow wave will induce torsion into the deck elements. The first 4 spans will be assessed for this effect, inclusive of the drop in section in span 4 and rocker complex. This will allow the torsion effect on the rocker complex, and adjacent structure, to be investigated.

4. ASSESSMENT CRITERIA

4.1 Live loading, Headroom Due to the sensitivity of this type of structure to settlement, and the importance of the structure to be considered, the settlements will be considered in a detailed assessment in combination with the following loads.

4.1.1 Loading relating to normal traffic under Authorized Weight (AW) Regulations 1998 and Construction and Use (C&U) Regulations 1996

40t Assessment live load represented by HA type UDL and KEL are to be applied in accordance with BD21/01 and BD101/11. .Accidental wheel loading to BD21/01 will be applied to the verges and central reserve to determine the worst case live loading effects.

4.1.2 Loading relating to General Order Traffic under Special Types General Order (STGO) Regulations 2003

The structure will be assessed for 37.5 units HB loading in accordance with BD 37/01.

4.1.3 Footway or footbridge live loading Footway loading in accordance with BD21/01 will be applied.

4.1.4 Loading relating to Special Order Traffic, provision for exceptional abnormal indivisible loads including location of vehicle track

Advice to be sought from CoW on SOT to be assessed.


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on deck cross-section

4.1.5 Any special loading not covered above

The structure will be assessed for differential settlement effects, as per section 6.3.

4.1.6 Heavy or high load route requirements and arrangements being made to preserve the route, including any provision for future heavier loads or future widening

Advice to be sought from CoW on heavy load requirements to be assessed.

4.1.7 Minimum headroom provided N/A

4.1.8 Authorities consulted and any special conditions required

City of Westminster

4.2 List of relevant documents from the TAS Refer to Appendix B

4.2.1 Additional relevant Standards It may be found necessary to utilise standards outside the normal suite of highway structure assessment standards, in which case these shall be identified and reported.

4.3 Proposed departures from Standards given in 4.2 and 4.2.1

N/A

4.4 Proposed methods for dealing with aspects not covered by Standards in 4.2 and 4.2.1

Post-tensioned bars will be assessed using standard engineering principals, using data obtained from the Buckton and Cuerel, New Waterloo Bridge, report.

5 STRUCTURAL ANALYSIS

5.1 Methods of analysis proposed for superstructure, substructure and foundations

The longitudinal settlement effects and transverse, bow wave, settlement effects will be determined by modelling Waterloo Bridge in LUSAS modeller as a 3D shell and beam model. Live loading to BD21/01 will be combined with calculated settlements from longitudinal and transverse settlement troughs. Stresses from the model on critical sections will be extracted and further hand calculations and spreadsheets will be used to analyse the stress state within them at a local scale. The caissons will be assumed to follow the settlement trough during settlement.

5.2 Description and diagram of idealised structure to be used for analysis

The model will be constructed using QTS4 thick shell elements, and BMS3 beam elements for the cross girders. BMS3 elements are straight beam elements in 3D for which shear deformations are included. The geometric properties are constant along their length. QTS4 elements are from a family of shell elements for the analysis of arbitrarily thick and thin curved shell geometries, including multiple branched


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junctions. The element formulation takes account of membrane, shear and flexural deformations. All shell elements will be placed geometrically at the centre of the section they are to model. Thick shell elements have been chosen as these elements allow for through-thickness shear deformation calculations, and, through-thickness shear stress outputs in LUSAS. As the depth of box girder top and bottom flange is relatively thick, it is felt that these outputs will be significant when evaluating the induced tunnel settlements. Where section properties vary with length, such as the box girder bottom flange, the geometric properties of these sections will be averaged or a worst case used. Diaphragms will be modelled throughout the structure, and given their appropriate section properties. These diaphragms are half height at the piers, but are of heavier gauge, this will be taken into account. The bridge will be modelled from the joint of the north abutment through to the south end of the drop in span in span 4. The south end of this section will be given supports with equivalent stiffness to the cantilever supporting it in span 4. The welded cage reinforcement will be assumed to have full continuity in assessing the structure, as the settlement loading does not affect the fatigue life of the structure, the welded cage will not be assessed. The pier shells do not contribute to the normal load path of the structure. Therefore, these will not been modelled as it is believed they may skew the results obtained from the assessment. If horizontal deflection, as a result of tunnel induced settlements, is observed to be greater than the 152mm stop limit, then the deflection will be restricted to this maximum in the model. Displacements of the foundations will be taken directly from the soil settlement troughs and applied to nodes at the base of the caissons. As the tunnel runs equidistance from each pier - the rotating piers will both settle and rotate by the same magnitude. The settlement has been applied directly from the bow wave settlement troughs to the outer edges of the affected pier caissons. All member connections are assumed to be rigidly


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connected. A diagram of the structure is provided in Appendix C.

5.3 Assumptions intended for calculation of structural element stiffness

Section dimensions will be ascertained from record drawings and from the bridge inspection. If there are areas of significant section loss discovered during the inspection these may be accounted for in the model.

5.4 Proposed earth pressure coefficients (ka, ko, or kp) to be used in the assessment of earth retaining elements

N/A

6 GEOTECHNICAL CONDITIONS

6.1 Acceptance of recommendations of Section 8 of the Geotechnical Report to be used in the assessment and reasons for any proposed changes

N/A

6.2 Geotechnical Report Highway Structure Summary Information

N/A

6.3 Differential settlement to be allowed for in the assessment of the structure

The proposed tunnel route is through the centre of span 3, see Appendix C, and therefore causes equal and opposing settlements and rotations on the affected bridge piers, for this reason only the settlement trough for pier 2 has been shown in Appendix C. The effects of settlement caused by 1% and 1.7% volume loss will be investigated. At 1.7%volume loss the foundation of pier 2 will have an applied settlement of 1.5 mm with an accompanying rotation of 194 x 10-6 radians rotating the top of the pier to the south. The foundation of pier 3 will have an applied settlement of 1.5mm with an accompanying rotation of 194 x 10-6 radians rotating the top of the pier to the north. No other supports will have any applied settlement.

Table 1 Summary of Settlements


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6.4 Geology Description Geotechnical data has been sourced from the British Geological Survey bore hole resource. The soil profile was found to be as follows; London clay = 29.5m Reading Formation = 19m Thanet Sand = 9m Chalk The tunnel centre line is located 44.2m below Ordinance Datum and therefore lies in the Reading Formation. See Appendix C for borehole data.

7 CHECKING

7.1 Proposed Category Proposed category for checking is Category3.

7.2 If Category 3, name of proposed independent Checker

To be advised

8 DRAWINGS AND DOCUMENTS

8.1 List of drawings (including numbers and revision reference) and documents accompanying the submission (See Appendix A)

W2_Contract Drawing – General Layout

8.2 List of construction and record drawings (including numbers) to be used in the assessment.

W1_Contract Drawing – Site Plan and Bore

Holes


W3_Contract Drawing – General Arrangement

North Side


Pier 1


Pier 2


South Side

W7_Contract Drawing – Longitudinal Sections

North and South Sides

W9_Contract Drawing – Longitudinal Sections

Pier 2

W10_Contract Drawings - General Sections

Abutments and Piers

W11_Contract Drawings – Details of

Proportions and Scantlings

W12_Contract Drawing – North Side

Stabilisation of Existing Vault

W17_Contract Drawing – Piers – Bearing Wall

W18_Contract Drawing – Piers

W21_Contract Drawing – Abutments – Bearing


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Wall

W22_Contract Drawing – Shore Cantilever –

Ribs C and D

W47_Contract Drawing – Stairways – North

Side

W51_Contract Drawing – Victoria Embankment

– Alterations to River Wall

W52_Contract Drawing – Victoria Embankment

– Alterations to Parapet

W53_Contract Drawings – Existing Temporary

Bridge – General Arrangement

ES/G/3765/108 – Waterloo Bridge Floodlighting

– General Details

LOLP/T/1008 – Strand Underpass Site Plan

VA/S/S/77/108/1/T.1-792 – Waterloo Bridge

Maintenance Plan

8.3 List of pile driving or other construction records

Not available

8.4 List of previous inspection and assessment reports

General Inspection Report dated March 2003

General Inspection Report Waterloo Bridge East dated March 2003

General Inspection Report Waterloo Bridge West dated March 2003

General Inspection Report Waterloo Bridge Mid-Level Gallery dated March 2003

General Inspection Report Waterloo Bridge North Stairs S17 dated March 2003

Principal Inspection Report of Waterloo Bridge East Slip Road (07E) dated May 2005

Principal Inspection of Waterloo Bridge East & West pedestrian Subways dated June 2005

Principal Inspection of Waterloo Bridge West Slip Road dated June 2005

Principal Inspection Report dated April 2006

Principal Inspection of Waterloo Road Retaining Wall (R06) dated September 2006

Principal Inspection of Waterloo Bridge Footbridge dated January 2007

Principal Inspection of Waterloo Road Retaining Wall (R07) dated January 2007

General Inspection Report Waterloo Bridge dated September 2008


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9 THE ABOVE IS SUBMITTED FOR ACCEPTANCE

Signed

Name

Charles Cocksedge

Position held

Assessment Team Leader

Engineering Qualifications

Name of Organization

AECOM

Date

10 THE ABOVE IS REJECTED/AGREED SUBJECT TO THE AMENDMENTS AND

CONDITIONS SHOWN BELOW

Signed

Name

David A. Yeoell

Position held

Assistant City Commissioner of Transportation

Engineering Qualifications

TAA

City of Westminster

Date

314-EA-TPI-BR015-000001-AF

APPENDIX A


314-EA-TPI-BR015-000001-AF

APPENDIX B British Standards

BS 5268 Part2: 2002 Structural Use of Timber

BS 5400 Steel Concrete and Composite Bridges

Part 1: 1988 General Statement (see BD 15 (DMRB 1.3.2))

Part 2: 2006 Specification for loads (as implemented by BD 37 (DMRB 1.3))

Part 3: 2000 CP for design of steel bridges (see BD 13 (DMRB 1.3))

Part 4: 1990 CP for design of concrete bridges (see BD 24 (DMRB 1.3.1))

Part 5: 2005 CP for design of composite bridges (see BD 16 (DMRB 1.3))

Part 9: 1983 Bridge bearings (see BD 20 (DMRB 2.3.1))

Part 10: 1999 CP for fatigue (see BD 9 (DMRB 1.3))

BS 5628: Part 1: 1992 Unreinforced Masonry

BS 5930: 1999 Site Investigations

BS 6031: 1981 Earthworks

BS 8002: 1994 Earth retaining structures

BS 8004: 1986 Foundations

BS 8118: 1991 The structural use of aluminium

BS EN 1317 -1-1998 Road Restraints System –

Part 1 Terminology and general criteria for test methods

Part 2 Performance classes, impact test acceptance criteria and test methods for safety barrier

Part 3 Performance classes, impact test acceptance criteria and test methods for crash cushions

DD - ENV 1317 -4- 2002 Road Restraints System –

Part 4 Terminals and Transitions

BS EN 14388 2005 Road Traffic Noise Reducing Devices - Specification

314-EA-TPI-BR015-000001-AF

Miscellaneous

Circular Roads No 61/72 – Routes for heavy and high abnormal loads

Railway Approval Code of Practice GC/RC5510: Recommendation for the Design of Bridges (2000)

Simplified Tables of External Loads on Buried Pipelines (1986)

Traffic Management act 2004

The Manual of Contract Documents for Highway Works (MCDHW)

Volume 1: Specification for Highway Works (March 1998 up to and including November 2009 amendments)

Volume 2: Notes for Guidance on the Specification for Highway Works (March 1998 up to and including November 2009 amendments)

Volume 3: Highway Construction (March 1998 up to and including November 2009 amendments)

The Design Manual for Roads and Bridges (DMRB)

Bridges and Structures, Advice Notes (BA Series)

BA 9/81 The Use of BS 5400: Part 10: 1980. Code of Practice for Fatigue

Amendment No. 1 - 1983

BA 16/97 The assessment of Highway Bridges and Structures.

Amendment No.1 - 1997

Amendment No.2 - 2001

BA 19/85 The Use of BS 5400: Part 3: 1982

BA 24/87 Early Thermal Cracking of Concrete

Amendment No. 1 – 1989

BA 26/94 Expansion Joints for Use in Highway Bridge Decks

BA 28/92 Evaluation of Maintenance Costs in Comparing Alternative Designs for Highway Structures

314-EA-TPI-BR015-000001-AF

BA 30/94 Strengthening of Concrete Highway Structures Using Externally Bonded Plates

BA 35/90 Inspection and Repairs of Concrete Highway Structures

BA 36/90 The Use of Permanent Formwork

BA 37/92 Priority Ranking of Existing Parapets

BA 38/93 Assessment of the Fatigue Life of Corroded or Damaged Reinforcing Bars

BA 39/93 Assessment of Reinforced Concrete Half – joints

BA 40/93 Tack Welding of Reinforcing Bars

BA 41/98 The Design and Appearance of Bridges

BA 42/96 The Design of Integral Bridges

BA 43/94 Strengthening, Repair and Monitoring of Post-tensioned Concrete Highway Bridge Decks

BA 44/96 Assessment of Concrete Highway Bridge and Structures

BA 47/99 Waterproofing and Surfacing of Concrete Bridge Decks

BA 50/93 Post- tensioned Concrete Bridges, Planning, Organisation and Methods for Carrying Out Special Inspections.

BA 51/95 The Assessment of Concrete Structures Affected by Steel Corrosion

BA 52/94 The Assessment of Concrete Highway Structures Affected by Alkali Silica Reactions

BA 53/94 Bracing Systems and the Use of U-Frames in Steel Highway Bridges

BA 54/94 Load Testing for Bridge Assessment

BA 55/06 The Assessment of Bridge Substructures and Foundations, Retaining Walls and Buried Structures

BA 57/01 Design for Durability

BA 58/94 Design of Bridges and Concrete Structures with External Unbonded Prestressing

BA 59/94 Design of Highway Bridges for Hydraulic Action

BA 67/96 Enclosure of Bridges

BA 68/97 Crib Retaining Walls

BA 72/03 Maintenance of Road Tunnels

BA 74/06 Assessment of Scour at Highway Bridges

BA 80/99 Use of Rockbolts

BA 82/00 Formation of Continuity Joints in Bridge Decks

BA 83/02 Cathodic Protection for Use in Reinforced Concrete Highway Structures

314-EA-TPI-BR015-000001-AF

BA 84/02 Use of Stainless Steel Reinforced in Highway Structures

BA 85/04 Paints and other protective coatings. Coatings for concrete highway structures and ancillary structures

BA 86/06 Advice notes on the non-destructive testing of highway structures

BA 87/04 Management of corrugated steel buried structures

BA 88/04 Management of buried concrete box structures

BA 92/07 The Use of Recycled Concrete Aggregates in Structural Concrete

BA 93/09 Structural Assessment of Bridges with Deck Hinges

Bridges and Structures, Standards (BD Series)

BD 2/05 Technical Approval of Highway Structures

BD 7/01 Weathering Steel for Highway Structures (2001)

BD 9/81 Implementation of BS 5400: Part 10: 1980. Code of Practice for Fatigue

BD 10/97 Design of Highway Structures in Areas of Mining Subsidence

BD 12/01 Design of Corrugated Steel Buried Structures with Spans greater than 0.9m and up to 8m

BD 13/06 Design of Steel Bridges. Use of BS 5400: Part 3: 2000

BD 15/92 General Principles for the Design and Construction of Bridges.

Use of BS 5400: Part 1: 1988

BD 16/82 Design of Composite Bridges. Use of BS 5400: Part 5: 1979

Amendment No. 1 - 1987

BD 20/92 Bridge Bearings Use of BD 5400: Part 9 1983

BD 21/01 The Assessment of Highway Bridges and Structures

BD 24/92 Design of Concrete Bridges. Use of BS 5400: Part 4: 1990

BD 27/86 Materials for Repair of Concrete Highway Structures

BD 28/87 Early Thermal Cracking of Concrete Amendment No 1 (1989)

BD 29/04 Design Criteria for Footbridges

BD 30/87 Backfilled Retaining Walls and Bridge Abutments

BD 31/01 The Design of Buried Concrete Box and Portal Frame Structures

BD 33/94 Expansion Joints for Use in Highway Bridge Decks

314-EA-TPI-BR015-000001-AF

BD 35/06 Quality Assurance Scheme for Paints and Similar Protective Coatings

BD 36/92 Evaluation of Maintenance Costs in Comparing Alternative Designs for Highway Structures

BD 37/01 Loads for Highway Bridges

BD 41/97 Reinforced Clay Brickwork Retaining Walls of Pocket Type and Grouted Cavity type Construction

BD 42/00 Design of Embedded Retaining walls and Bridge Abutments

BD 43/03 Criteria and Material for the Impregnation of Concrete Highway Structures

BD 44/95 The Assessment of Concrete Highway Bridges and Structures

BD 45/93 Identification Marking of Highway Structures

BD 47/99 Waterproofing and Surfacing of Concrete Bridge Decks

BD 48/93 The Assessment and Strengthening of Highway Bridge Supports

BD 49/01 Design Rules for Aerodynamic Effect on Bridges

BD 51/98 Design Criteria for Portal and Cantilever Sign/Signal Gantries

BD 53/95 Inspection & Records for Road Tunnels

BD 54/93 Post -tensioned Concrete Bridge Prioritisation of Special Inspections

BD 56/10 The Assessment of Steel Highway Bridges and Structures

BD 57/01 Design for Durability

BD 58/94 The Design of Concrete Highway Bridges and Structures with External and Unbonded Prestressing Design of Highway Bridges for Vehicle Collision

BD 60/04 The Design of Highway Bridges for Collision Loads

BD 61/10 The Assessment of Composite Highway Bridges and Structures

BD 62/07 As Built, Operational and Maintenance Records for Highway Structures

BD 63/07 Inspection of Highway Structures

BD 65/97 Design Criteria for Collision Protector Beams

BD 67/96 Enclosures of Bridges

BD 68/97 Crib Retaining Walls

BD 70/03 Strengthening/ Reinforced Soil and Other Fills for Retaining Walls and Bridge Abutments (Use of BS 8006:1995)

BD 74/00 Foundations

BD 78/99 Design of Road Tunnels

314-EA-TPI-BR015-000001-AF

BD 79/06 The Management of Sub-standard Highway Structures

BD 81/02 Use of Compressive Membrane Action in Bridge Decks

BD 82/00 Design of Buried Rigid Pipes

BD 84/02 Strengthening of Concrete Bridge Supports for Vehicle Impact using Fibre Reinforced Polymers

BD 85/08 Strengthening Highway Structures Using Externally Bonded Fibre Reinforced Polymer

BD 86/11 The Assessment of Highway Bridges & Structures For The Effects of Special Types General Order (STGO) and Special Order (SO) Vehicles.

BD 87/05 Maintenance Painting of Steelwork

BD 89/03 The Conservation of Highway Structures

BD 90/05 Design of FRP Bridges and Highway Structures

BD 91/04 Unreinforced Masonry Arch Bridges

BD 94/07 Design of minor structures

BD 95/07 Treatment of Existing Structures on Highway Widening Schemes

BD 101/11 Structural Review and Assessment of Highway Structures

Bridges and Structures, Technical Memoranda (BE Series)

BE 13 Fatigue Risk in Bailey Bridges Apr

BE 23 Shear Key Decks Amendment No. 1 to Annex

BE 5/75 Rules for the Design and Use of Freyssinet Concrete Hinges in Highway Structures

BE 7/04 Departmental Standard (Interim) Motorway Sign/Signal Gantries

General Design Requirements (GD Series)

GD 01/08 Introduction to the Design Manual for Roads and Bridges (DMRB)

GD 02/08 Quality Management System for Highway Design

Traffic Engineering and Control, Standards (TD Series)

314-EA-TPI-BR015-000001-AF

None applicable

Highways, Advice Notes (HA Series)

None applicable

Highways, Standards (HD Series)

None applicable

314-EA-TPI-BR015-000001-AF

APPENDIX C

List of documents:

1. 60099445-BR015 Soil Parameters Table

2. 60099445-TN03_Rev1 - Predicted settlements results comparison

3. Waterloo Road Bridge Tunnel Section & Settlement Troughs (1.7% & 1.0% volume loss)

4. 60099445-BB LUSAS model Waterloo Bridge

5. Available Borehole Data and Borehole logs

Copyright notice Copyright © Thames Water Utilities Limited September 2013. All rights reserved. Any plans, drawings, designs and materials (materials) submitted by Thames Water Utilities Limited (Thames Water) as part of this application for Development Consent to the Planning Inspectorate are protected by copyright. You may only use this material (including making copies of it) in order to (a) inspect those plans, drawings, designs and materials at a more convenient time or place; or (b) to facilitate the exercise of a right to participate in the pre-examination or examination stages of the application which is available under the Planning Act 2008 and related regulations. Use for any other purpose is prohibited and further copies must not be made without the prior written consent of Thames Water. Thames Water Utilities LimitedClearwater Court, Vastern Road, Reading RG1 8DB The Thames Water logo and Thames Tideway Tunnel logo are © Thames Water Utilities Limited. All rights reserved.

Copyright notice Copyright © Thames Water Utilities Limited September 2013. All rights reserved. Any plans, drawings, designs and materials (materials) submitted by Thames Water Utilities Limited (Thames Water) as part of this application for Development Consent to the Planning Inspectorate are protected by copyright. You may only use this material (including making copies of it) in order to (a) inspect those plans, drawings, designs and materials at a more convenient time or place; or (b) to facilitate the exercise of a right to participate in the pre-examination or examination stages of the application which is available under the Planning Act 2008 and related regulations. Use for any other purpose is prohibited and further copies must not be made without the prior written consent of Thames Water. Thames Water Utilities LimitedClearwater Court, Vastern Road, Reading RG1 8DB The Thames Water logo and Thames Tideway Tunnel logo are © Thames Water Utilities Limited. All rights reserved.

10243-A4P-Copyright-imp-V01.pdf p1 12:03:39 September 21, 2013