viaduct and bridge construction methods adopted at mtr sil(e

2013/8/29 MTR Corporation Limited Page 1Page 12013/8/29 Page 12013/8/29MTR Corporation Limited Page 1

MTR SIL(E) 903 Viaduct Construction Team28-8-2013

Viaduct and bridge construction methods adopted at MTR SIL(E) Contract 903

2013/8/29MTR Corporation Limited

Content

1. About SIL(E) Contract 903

2. Viaduct Construction

2.1 Value Engineering for Viaduct

2.2 Viaduct construction by Pre-cast segmental method

2.3 Stakeholder Management

3. Aberdeen Channel Bridge (ACB) Construction

3.1 Value Engineering for Aberdeen Channel Bridge

3.2 Bridge construction by in-situ balance cantilever


4. Q&A



Works Contract 901

Works Contract 902

Works Contract 903OCP

LETSOH

WCH

ADM

Works Contract 907 / 908Works Contract 904


Wong ChukHang Station

Ocean Park Station

Aberdeen ChannelBridge

Viaduct

Nullah Works

Viaduct




Viaduct B

Viaduct C

Ocean Park Station

Ocean Park Station

Wong ChukHang

Station



Wong ChukHang

Station

Viaduct D

Aberdeen Channel Bridge



1. 2 Contractors can be selected at an early stage to help the Employer to identify value engineering solutions

2. The selected Contractor will have more time to mobilise sufficient resources and plan the works well before the actual commencement of the Contract.

3. The Employer and his construction team will be more proactive to help the Contractor to use the cheapest method to complete the project.

4. This contract arrangement is beneficial to foster a genuine partnering relationship between the Employer and the Contractor.

5. This form of contract facilities early identification of risks and allows these risks to be better managed during the construction stage, thus increasing the certainty of project delivery.

Beauty of Target Cost Contract



4 main benefits to use elevated railway for this section of SIL(E) are:

1. Less spoil will be generated from this Contract;

2. The passenger will be able to enjoy the beautiful scenery from Ocean Park to Ap Lei Chau;

3. The connection details between the Ocean Park Station and the main railway line will be much simpler and user friendly;

4. The elevated railway requires less land during construction compared to a tunnel option, which addresses the lack of available land in Southern District;


Key information of SIL(E) Viaduct• Length of the viaduct is approx. 2 km;• Viaduct height is approx. 10 to 25m subject to topographical condition;• There are 47 nos. of viaduct piers with span length from 21m to 50m; and• 628 nos. of precast segments, 22-55 tonnes each.

2. Key information of SIL(E) Viaduct

Wong Chuk Hang Station

Ocean Park StationSegmental construction

casting in-situ construction

Viaduct DViaduct C

Viaduct B


Coloured Translucent Panels Where Required

Viaduct Pier

Opaque Panels at Absorptive Parapet

Barrier

Overhead Lines

Proposed Noise Barrier - Perspective Proposed Noise Barrier - Section

2m

Countershading

Track-Side Op’s

Noise Barrier - Integrated Approach


Front Elevation Side Elevation Front Elevation at Portal

Rounded Piers

Profiled Capital

Planting at BottomOf Pier

Consistent Approachfor Portal Piers

13m

4000

4000

Typical Viaduct Section



2.1 Value Engineering for Viaduct


Viaduct B

Viaduct B


2.1.1 Value Engineering for Viaduct B

Viaduct construction in the vicinity of the road with heavy traffic

MTR Corporation Limited 2013/8/29


Change in piling design – Use a large diameter pile to replace a group of smaller diameter piles

Conforming design

Single 2.8m Dia. Bored Pile

Alternative design

3 nos of 1.5m dia piles

Wong ChukHang Road

Wong ChukHang Road

Wong ChukHang Road

Wong ChukHang Road


Legend

Piles

Pile cap

Traffic flow

Carriageway


B3

Conforming design

B3

Alternative design

‧Extent of works area required was greatly reduced

‧Less impact on road traffic

Change in Pilecap Design – Use a smaller rectangular pilecap to replace a larger irregular pilecap

Wong Chuk Hang Road

Wong Chuk Hang Road



Change in Pilecap Design – Use a smaller rectangular pilecap to replace a larger irregular pilecap

Revised Pile Cap

Existing 132 kV HEC cables

Existing 132 kV HEC cables

Original Pile Cap

Conforming design

Alternative design

‧Minimize the conflict with the existing utilities


1) Extent of works area required was greatly reduced2) Less impact on the road traffic3) Minimize the conflict with the existing utilities4) Cheaper and faster to construct the piling and pilecap works

Advantages of the alternative design over the conforming design

1) Volume of pile cap - Approx. 320 m3

2) Less construction and ELS required 1) Volume of pile cap - Approx. 480 m3

2) More construction and ELS required Pile caps

2.0 m to 2.8 m1.5 mSize of bored piles

18

Conforming design

9Number of bored piles

Alternative design


Comparison between conforming design and alternative design


Viaduct C

Viaduct C

Nullah


2.1.2 Value Engineering for Viaduct C

Viaduct construction over nullah


Conforming design


Alternative design

1. Reduce the number of portal from 11 to 8 2. Change in piling design – Use a large diameter pile to replace a group of smaller diameter piles


Approx. 50 mApprox. 35 mSpan length

1) Reduce construction time for bored piles and portals2) Minimize construction activities inside the nullah - critical to programme3) Less visual impact with wider spacing of portal structures4) Minimize the conflicts with the existing utilities


811Number of portals

1.8 m (C1, C2 and C11 Piers)2.0 m (Portals)

1.5 m (C1, C2 and C13 Piers)1.8 m or 2.2 m (Portals)

Size of bored piles

56

Conforming design

28Number of bored piles

Alternative design




Viaduct D

Viaduct D


2.1.3 Value Engineering for Viaduct D (from D13 to D18)

Viaduct construction in hilly area


Conforming Design Alternatives Design

Spread Footing found on Rock

3 nos of 1.5m dia piles

Rock Dowels

Inferred Rockhead

Change in Foundation Design – Replace bored pile by spread footing



- More timber formworks- Better quality control in casting yard- Environmental friendly - steel mould replace timber

formwork Advantage

Limitation- Construction is relatively simple and

faster with the use of a tower crane

In-situ Deck

- Difficult access at hilly area for erection of precast segment

Precast segmental deck

Change in viaduct design - Replace precast segmental deck by in-situ deck

Hilly area

Replace precast segmental deck by in-situ deck

Segmental construction



Spread footing found on rock with rock dowels per column

3 nos of 1.5m dia piles per column

Type of pile per column

In-situ deckPrecast segmental deckViaduct type

1) No heavy piling plant is required in the hilly area

2) Less time to complete the foundation works as footing can be constructed simultaneously

3) The size of the haul road and the ELS works required can be reduced

4) The delivery of materials are relatively simple with the use of a tower crane or a mobile crane


Conforming design Alternative design





2.2 Viaduct Construction by Pre-cast Segmental Method


2.2.1 Erection by Crane

2.2 Pre-cast segmental method

2.2.2 Erection by Beam-and-Winch

Two erection methods are being adopted:



Step 1

B4B4

B5

Step 2



B4 B4B5 B5Closure beams

Step 3 Step 4


• Beam-and-Winch technology was introduced in the SIL(E) project to enhance the merits of precast segment erection method


B4B4

B5 B5

Step 1 Step 2



B4 B4B5 B5Closure beams

Step 3 Step 4


Beam-and-Winch Launching gantry

Approx. one monthApprox. a weekTime required for machine assembly

Approx. 100m in length and 10m wideMore than 10 times larger than Beam-and-Winch equipment in size

Approx. 8m in length and 10mwide

ScaleLaunching GantryBeam-and-Winch

2.2.3 Beam-and-Winch and Launching Gantry


Advantage of Beam-and-Winch over Launching Gantry • Less road space required, less disturbance to the traffic• Less construction time required • More flexibility and efficiency in works arrangement

Limitation of Beam-and-Winch • Allowance in Permanent Works Design• Mobile Crane required for mobilization from pier to pier.

2.2.3 Beam-and-Winch and Launching GantryAdvantage and Limitation of Beam-and-Winch


Independent checking system for segment erection

2.2.4 Safety Measures

Checklist of segment erection Checklist of B&W operation


Key measures to minimize impacts on road traffic:1. Adopt Pre-cast segmental method2. Use Beam-and-Winch3. Night-time erection to minimize traffic impact on the public

3) Night time erection

2.2.5 Measures to minimize impacts on Road Traffic

2) Beam-and-Winch1) Pre-cast segmental method


2.3.1 Major Stakeholders around the Viaduct B & C

San Wai Village

TWGHs Wong ChukHang Complex

Ocean Park

Station

Viaduct

Viaduct

Police College Ocean Park

Bus Depot

Aberdeen Tunnel


Jockey ClubRehabilitatio

n CentreHoly SpiritSeminary

Tai Wong YeTemple

Little Sisters of the Poor

St. Mary’s Home for the

Aged

Viaduct

Wong Chuk Hang

Station

NLSR Cooked Food

Market

2.3.2 Major Stakeholders around the Viaduct D


Visit to the TWGHs Wong ChukHang Complex

Painting activity in Little Sisters of the Poor

Allowance for Tai Wong Ye Temple’s Yu Lam Festival event

JCRC visit and regular meeting

2.3.3 Stakeholder Engagement

Community Liaison Group Meeting

Football Match with Police College


3. Aberdeen Channel Bridge Construction


Aberdeen Channel

SIL(E) Aberdeen Channel Bridge

Existing Ap Lei Chau Bridge

N

58m

115m

73m

ASectionTotal Length = 250m

Max

7m

3. Aberdeen Channel Bridge

A

A


Photomontage of Aberdeen Channel Bridge

3. Aberdeen Channel Bridge

Aberdeen Channel Bridge (as of June 2013)


Conforming Arrangement

16 pairs segments (~3.5m long) 16 pairs segments (~3.5m long)

Alternative Arrangement

10 pairs segments (~4.3m long) 14 pairs segments (~4.3m long)

Falsework eliminated

Longer cantilever length for segment construction

One unbalanced cantilever segment

E2E3

E3 E2


Temporary pier bracingTemporary pier bracing

Temporary pier bracing

E1E2E3E4

12m insitu end span on falsework

Hill

Hill


160 tons130 tonsMax. segment weight

65 m60 mMax. cantilever length

1) Segment weight in alternative design is heavier2) One set of form traveller instead of two sets of form traveller

is required to meet the programme3) Temporary bracing at E3 pier eliminated4) Scaffolding for end span near E1 eliminated5) Advantage to construction programme6) The alternative design can provide early access for P-way

construction

Remark:

1912 Number of strands per cantilever tendons

~ 40 weeks~ 50 weeksPeriod for segment construction

32 pairs

Conforming design

24 pairsNumber of segments

Alternative design




3.2 Bridge construction by in-situ balance cantilever



3.2 ACB – Comparison of different construction methods

Disadvantage1) Falsework cannot be

erected across the Aberdeen Channel

Disadvantage1)Barge for segment

erection is too large to gain access to the bridge

2) Segment (max 160T) too heavy for lifting

3) Disruption to Navigation Channel during segment erection

Advantage1) Only one set of form

traveller is required2) Without affecting the

marine traffic underneath the bridge

3) No heavy lifting involved 4) Cheapest and fastest

way to build this bridge

Advantage and disadvantage

Cast bridge span by span with the support by falsework

Segment pre-cast and erection

Cast in-situ segments by balanced cantilever method with form traveller

Description

Cast in-situ span by spanPre-cast segmental methodCast in-situ segments by balanced cantilever

(Selected option)


3.2.1 ACB – Construction Sequence

Stage 1 – Pier Table construction at E2

Stage 2 – Pier Table construction at E3 - Erect form traveller at E2


Stage 3 – Complete cantilever span at E2 by insitu balanced cantilever method

Stage 4 – Launch back form traveller & remove tower crane from E2



Stage 5 – Tower Crane & form traveller removed from E2

Stage 6 – Erect tower crane & form traveller at E3



Stage 7 – Complete E3 cantilever span by insitu balanced cantilever method

Stage 8 – Cast Mid-span stitch



Stage 9 – Cast unbalanced segment at E4

Stage 10 – Cast End-span stitch at E4



3.2.2 Modular Form Traveller (MFT)

Major component:Modular Form Traveller• Main Frame x 2• Front Transverse Truss x 1• Rear Transverse Truss x 1• Rear Anchorage x 2• Rail Beam x 2

Formwork system• Inner Form• Outer Form• Bottom Form


General characteristics of Modular Form Traveller:

Bridge alignment• Gradient of +/-5%• Cross-fall of +/-5%• Minimum curve in plan of 500m

radius

Segment geometry• Maximum length of 5m• Maximum weight of 180 tons (with 2

main frames)• Single or multiple cells• Vertical or inclined webs

System capacity: 180 tons

Load test could be carried out prior to assembly



Rear truss

Bottom Form

Front truss Wall Form

3.2.2 Modular Form Traveller (MFT)Main frames


3.3.1 Stakeholders around Aberdeen Channel Bridge


Dragon Boat Association

Aberdeen Boat Club

Marine Police Port

Tai Shue Wan

Aberdeen Channel

Sham WanJumbo

Restaurant

Kaito


Key measures to minimize marine traffic impact:1. Use cast-insitu balanced cantilever method

2. Maintain navigation channel

3. Advance notice to all marine users about the construction works

4. Use of guard boat

3.3.2 Minimize impact on Marine Traffic

40m min. wide

14 m min. high

2. Navigation Channel

1. Cast-insitu balanced cantilever method


4. Use of guard boat 3. Early notice to all marine users about the construction works

3.3.2 Minimize impact on Marine Traffic


Use of silt curtain

3.3.3 Minimize impact on Marine Environment

Key measures to minimize marine environment impact:

1. Use of silt curtain2. Use of temporary steel formwork for pile cap construction

Use of temporary steel formwork for pile cap construction


3.3.4 Entertain the need of Dragon Boat Association

Relocate the existing dragon boats to the new permanent storage area for the Dragon Boat Association before the commencement of the construction on site


Existing storage area for dragon boat before bridge constructionNew permanent storage area for

dragon boat

2013/8/29MTR Corporation Limited Page 73

多謝Q & A

viaduct and bridge construction methods adopted at mtr sil(e

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