condition 2012-256 - responsive 2

7/30/2019 Condition 2012-256 - Responsive 2

1/39

Obtained by Bob Mackin via Freedom of Information

[email protected]

twitter.com/bobmackin


2/39

Report

City of Vancouver

Burrard Street BridgeCondition Assessment Report

April 2012


3/39


4/39

REPORT

iP:\20112789\00_Burrard_Rehab_Des\Engineering\12.00_Inspections\RPT_CAR_18April2012_Final\rpt_van_conditionassessment_20120418_dc.doc

Table of Contents

SECTION PAGE NO.

Table of Contents i

1 Introduction 1

1.1 Project Background 1

1.2 Project Personnel 1

1.3 Inspection 1

1.4 Existing Information 21.5 Structural Description 4

1.6 Bridge Description 5

1.7 Condition Rating System 6

2 Inspection Results 6

2.1 Deck Elements 6

3 General Discussion 27

7 Closure 34

s.13(1) and s.17(1)(c) & (f)

s.13(1) and s.17(1)(c) & (f)

s.13(1) and s.17(1)(c) & (f)


5/39

City of Vancouver

iiP:\20112789\00_Burrard_Rehab_Des\Engineering\12.00_Inspections\RPT_CAR_18April2012_Final\rpt_van_conditionassessment_20120418_dc.doc

s.13(1) and s.17(1)(c) & (f)


6/39

REPORT

1P:\20112789\00_Burrard_Rehab_Des\Engineering\12.00_Inspections\RPT_CAR_18April2012_Final\rpt_van_conditionassessment_20120418_dc.doc

1 Introduction

1.1 Project Background

The Burrard Street Bridge is a civic icon that has been recognized as a significant heritage

structure in the City of Vancouver. Constructed in 1930, the bridge serves as a critical

transportation link between Vancouver south and the downtown core. The bridge comprises

twenty-six concrete girder approach spans, four steel under-trussed spans, and a through trussed

main span.

The City of Vancouver (City) retained Associated Engineering (AE) to provide engineering

services for the Retrofit and Rehabilitation of the Burrard Bridge. AE has undertaken a

targeted condition assessment and close-proximity inspection to verify the existing base-line

condition, provide information needed for concept development and evaluation, as well as repair

data and quantities to enable sound estimating for the tender stage of the project.

We have teamed with Levelton Consultants Ltd. (Levelton), Trans Canada Coatings Consultants

Ltd. (TC3), Donald Luxton & Associates Inc. (DLA), and Iredale Group Architecture (Iredale), to

complete the various aspects of the inspection. This report summarizes our findings from this

targeted condition assessment and close-proximity inspection.

1.2 Project Personnel

David Chen, B.Eng., P.Eng., and Tim Aucott, B.Eng. (Hons.), P.Eng., conducted the inspection;

Russ Raine, BSc, Chemistry, of TC3 and David Smith, MScE., P.Eng., of Levelton joined the

inspection team to inspect key areas of the bridge.

David Chen and Tim Aucott prepared this report, while Shane Cook, M.A.Sc., P.Eng., reviewed it.

Levelton and TC3 have both prepared reports, which focused on their specific aspects of the

inspection. The detailed report from Levelton, prepared by David Smith, will be submitted

separately from this report once the concrete test results are analyzed. The detailed report from

TC3, prepared by Russell Raine, is included in the Appendix E of this report.

1.3 Inspection

AE completed the inspections between April 27 and June 17 in several stages. The first stage

comprised a visual walk over inspection. We visually assessed the approach spans concretegirders, deck soffit, and concrete bents from the ground level. We also made general observation

on the condition of the bridge deck surface, deck joints, sidewalks, and parapet.


7/39

City of Vancouver


The findings from the visual inspection were verified through a second stage targeted detailed

close-SUR[LPLW\LQVSHFWLRQRQVHOHFWHGDUHDVRIWKHEULGJHDSSURDFKVSDQV:HXVHGDQDQGD

ERRPOLIWWRDFFHVVWKHFRQFUHWHJLUGHUVGHFNVRIILWDQGEHQWVWRZLWKLQWRXFKLQJGLVWDQFH

Levelton accompanied AE on the inspection of select areas of the concrete approach spans to

investigate the concrete condition and collect samples for testing.

The third stage comprises a targeted detailed close-proximity inspection on the steel under-trussed

spans and the through trussed main span (Spans 22 to 26). Access to the lower portion of the

deck truss spans and main through truss span was facilitated by using the safety line system

installed along the bottom truss chords and the floor beams. We utilized the BC Ministry of

Transportation and InfrastructurHV%ULGJH,QVSHFWLRQ6QRRSHU7UXFNWRJDLQDFFHVVWRWKH east

half of the upper portion of the deck trusses, as well as the deck soffit of Spans 22 and 23. We also

performed a targeted detailed inspection on the east half of the above deck portions of main

WKURXJKWUXVVVSDQXVLQJDQERRPOLIW7&DFFRPSDQLHG$(GXULQJWKHVHLQVSHFWLRQVWR

assess the condition of the protective paint coating on the steel truss elements.

The fourth stage of the inspection consists of additional detailed inspections on specific bridge

elements and targeted material testing. We conducted detailed visual inspection of the Pier 1

Stairwell and the Pier 4 Overhead Gallery. During the Pier 1 Stairwell inspection, representatives

from Levelton, DLA, and Iredale were on site to make observation on the concrete condition as well

as the heritage and architectural features. AE and Levelton performed a targeted detailed condition

survey of the bridge west sidewalk; a limited chain-drag inspection was conducted on the west

sidewalk, and concrete samples were collected for testing. Levelton also took bridge deck concrete

sample at pre-selected locations along the deck for testing.

1.4 Existing Information

The City provided AE with the following record information prior to the commencement of the

inspection.

1.4.1 Reports and Information

Burrard Bridge Brief Summary of Previous Seismic Upgrades by Buckland and

Taylor Ltd. April 2011.

Not responsive


8/39

ReportBurrard Street Bridge

Condition Assessment Report


Not responsive

s.13(1) and s.17(1)(c) & (f)


9/39

City of Vancouver


1.5 Structural Description

The Burrard Bridge currently carries five traffic lanes, two bike lanes, and a pedestrian sidewalk

over False Creek. The bridge comprises a 24.4 m wide cast-in-place (CIP) reinforced concretedeck with integral concrete sidewalks, concrete parapets, continuous concrete fascia beams, and

an asbestos-modified asphalt overlay. A General Arrangement drawing showing span

arrangements and typical deck cross sections is provided in Appendix A.

The approach spans vary in length between 5.5 m and 27.1 m and the girders vary between a two-

span continuous to a four-span continuous arrangement. The approach span superstructure

consists of three CIP reinforced concrete girders with integral reinforced concrete diaphragms and

cantilevered outriggers.

Concrete girders are supported by sliding bearings at the south abutment and the south end of the

Pier Bent 4; girders are supported by rocker bearings at the north abutment. Steel pin bearings or

rocker bearings are supporting the concrete girders on each side of the reinforced concrete pier

bents below the expansion joints. The superstructure of the approach spans has been seismically

retrofitted through the installation of longitudinal and lateral restrainers at the expansion joint

locations.

The abutments are CIP reinforced concrete supported from spread footing. There is a staircase

adjacent to each of the four wing walls, the staircases at the south abutment connect to unpaved

trails beneath the bridge and the staircases at the north abutment connect to the sidewalk of an

unnamed service road beneath the bridge.

The approach span pier bents comprise square, reinforced concrete columns with integral cross

beams supported from spread footings. The bents have either a two or a three column

arrangement and were likely designed this way to accommodate a railway line beneath the bridge.

The pier bents at the expansion joint locations (Bents 4, 7, 10, 13, 16, 19, and 24) have been

seismically retrofitted through the installation of new concrete shear walls, footing overlays, and

concrete jacketing of the cross beam and column; in addition, Bent 4 has bearing seat extension

brackets installed.

The truss spans consist of four simply supported deck truss spans (Spans 22, 23, 25, 26) and one

simply supported through-truss main span (Span 24). The truss span superstructure consists of

riveted, built-up, painted steel sections connected via gusset plates at the node locations. The top

and bottom chords, truss verticals, truss diagonals, and portal cross-beams (S24 only) are formed

from built up box sections, some of which have latticed top and bottom cover. The top plan

bracings of the trough-truss span and bottom plan bracings of the deck truss spans comprise built

up I-sections with latticed webs. The top plan bracings and intermediate diaphragms of the deck

truss spans, as well as the bottom plan bracings and the portal diaphragms of the trough-truss

span, comprise back-to-back angles.


10/39




The end cross bracing diaphragms of the deck truss spans comprise built-up box sections that

connect into the gussets at the ends of the truss chords. The bottom chord gusset plates at the

end of each truss span are integral with the vertical member and the bearing assembly at the pier

bearing locations. The truss spans are supported by CIP reinforced concrete piers bearing on piles

at Pier 1 and on spread footings at Piers 2 through 6.

The CIP concrete deck is supported by a system of longitudinally spanning stringers and

transversely spanning floor beams. The deck truss spans have seven interior stingers and four

exterior stringers (two at each deck overhang) between floor beams. The through-truss span has

seven interior stringers between floor beams. The stringers are connected to the webs of the floor

beams via a riveted web splice; Stringers A, F, and K in the deck truss spans are supported by

additional brackets on the floor beam web. Floor beams coincide with node locations and are

simply supported from the top of the top chord in the deck truss spans. For the through-truss span

the floor beams are connected directly into the lower truss cord nodes.

A seismic retrofit of the truss spans, included installation of new stringer support brackets beneath

the expansion joint at Pier 2 and Pier 5, as well as the replacement of the deck truss end

diaphragm bracing, bottom lateral bracings, and installation of seismic isolation bearings, was

previously undertaken.

1.6 Bridge Description

We have numbered the bridge spans, bents, and piers from south to north to correlate with the

record drawings and previous inspection reports. To be consistent with the record drawings and

previous inspection reports, we did not assigned number 21 on approach pier bents. Piers

supporting the truss spans (Spans 22 to 26) are number from south to north as Piers 1 through

Pier 6. Refer to the General Arrangement drawings provided in Appendix A for details. The

bridge is described as following:

South approach spans (Spans 1 to 21) - CIP concrete girders supported on the south

abutment, Bents 1 to 20, and Pier 1.

South deck trusses (Spans 22 and 23) - painted steel trusses supported on Piers 1 to 3.

Trough truss (Span 24) - painted steel truss supported on Piers 3 and 4.

North deck trusses (Spans 25 and 26) - painted steel trusses supported on Pier 4 to 6.

North approach spans (Spans 27 to 31) - CIP concrete girders supported on Pier 6, Bents

22 to 25, and the north abutment.

Longitudinally, we have numbered the approach span concrete diaphragms, cantilevered outriggers

and deck bays from south to north. Transversely, approach span concrete girders, diaphragms,

DQGEHQWFROXPQVDUHODEHOOHGDV:HVW0LGGOHDQG(DVW


11/39

City of Vancouver


For each of the five truss spans, we have numbered the truss nodes from south to north (starting

with Node 0); the numbering is not continuous across spans. The trusses are identified as either

the East Truss or the West Truss, and elements at the top of the truss, such as the top chord are

GHILQHGDV8SSHUZKHUHDVHOHPHQWVDWWKHERWWRPRIWKHWUXVVVX ch as the bottom chord or

ERWWRPSODQEUDFLQJDUHGHILQHGDV/RZHU(DFKWUXVVHOHPHQWLVGHILQHGE\WKHQRGHVWKDWLW

spans between (For example: L0W to U1W describes the first diagonal member of the West truss

starting at node Lower 0 and ending at node Upper 1). The floor beams are coincident with the

truss nodes and numbered from south to north to correspond with the nodes. The truss stringers

DUHODEHOOHGDV$WKURXJK.IURPZHVWWRHDVW

1.7 Condition Rating System

We rated the individual compoQHQWVRIWKHEULGJHXVLQJWKH&LW\RI9DQFRXYHUVEULGJHLQVSHFWLRQ

system. The system rates the condition of each component as:

Good (4).

Fair (3).

Poor (2).

Very Poor (1).

The percentage of each individual component falling within that condition state has been recorded.

A City of Vancouver bridge inspection form for the Burrard Street Bridge is included in Appendix B.

7KHOHWWHU(RQWKHLQVSHFWLRQIRUPGHQRWHVWKDWWKHFRPSRQHQWLVLQDQH[FHOOHQWRUDV

new condition.

7KHOHWWHU1RQWKHLQVSHFW ion form denotes that the inspection team could not adequately

inspect the component.

7KHOHWWHU;RQWKHLQVSHFWLRQIRUPGHQRWHVDFRPSRQHQWWKDWLVQRWSUHVHQWDWWKH

location considered. This condition occurs when components such as wing walls or

retaining walls are not present at all four corners of a bridge.

2 Inspection Results

The bridge is generally in a fair condition. The following sections of the report provide a breakdown

of the inspection findings on an element by element basis.

2.1 Deck Elements

Levelton has completed a detailed condition assessment with concrete sample tests on the deck

VRIILWZHVWVLGHZDONDQGZHVWH[WHULRUSDUDSHW/HYHOWRQVDVVHVVPHQWDQGWHVWUHVXOWVDUH

summarized and discussed in a separate report by Levelton to follow.


12/39

an s. c ,


13/39

an s.an s. c ,


14/39

an s.an s. c ,


15/39

an s.an s. c ,


16/39

an s.an s. c ,


17/39

an s.an s. c ,


18/39

an s.an s. c ,


19/39

an s.an s. c ,


20/39

an s.an s. c ,


21/39

an s.an s. c ,


22/39

an s.an s. c ,


23/39

an s.an s. c ,


24/39

an s.an s. c ,


25/39

an s.an s. c ,


26/39

an s.an s. c ,


27/39

an s.an s. c ,


28/39

an s.an s. c ,


29/39

an s.an s. c ,


30/39

an s.an s. c ,


31/39

an s.an s. c ,


32/39

13(1) and s.17(1)(f)

s.13(1) and s.17(1)(f)

an s. c ,


33/39

an s.an s. c ,


34/39

an s.an s. c ,


35/39

an s.an s. c ,


36/39

an s.an s. c ,


37/39

an s.an s. c ,


38/39




6 Monitoring and Further Work

During the inspection, we observed numerous previously recorded, concrete cracks on the deck

soffit which have developed into concrete spalls within the past four years. This observation, along

with the respectable amount of localized concrete delamination and active water seepage atconstruction joints and concrete cracks on the deck soffit, indicates that the deterioration of the

concrete deck of the Burrard Street Bridge has been progressing since the 2007 Inspections by

Delcan Corporation. As the deck concrete continues to age, it will likely require major repair in the

near future. Therefore, we recommend that the City to investigate renewal or rehabilitation options

for the concrete deck of the Burrard Street Bridge. The City should also consider incorporating

major bridge deck rehabilitation for Burrard Street Bridge in future financial planning.

s.13(1) and s.17(1)(c), (d) & (f)


39/39

condition 2012-256 - responsive 2

Documents