Matt Carter | Associate Director
2nd International Seminar on Design & Construction of Second Penang Bridge
Construction of the Superstructure of Major Sea Crossings
2 Second Penang Bridge
3 Typical Sea Crossing Bridges
Donghai Bridge Incheon Bridge
Penang Bridge Shenzhen Western Corridor
4 Long Section
Scale H:V = 10:1
Maximum water depth = 10m
Typical water depth = 2 to 3m
5 Stonecutters Bridge, Hong Kong
6 Second Penang Bridge, Malaysia
7 Substructure optimization
Substructure is typically around one third of the total cost
Innovative design gives substantial savings
Depends on ground conditions
Innovations: - Construction methods
- Lateral pile load tests
- Articulation
- Seismic isolation
Typical Superstructure
9
Quality – Production line casting in a controlled environment
Economy – Repetitive operations, re-use of equipment
Safety – Minimise working at height and over water
Advantages of precast construction
10
Quality Cost Speed of
Construction Durability Safety
Environmental Impact
Aesthetics
Design Drivers
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Quality Cost Speed of Construction
Durability Safety Environmental
Impact Aesthetics
Design Drivers
12
For given site conditions there will be an optimum economic span
With current technologies in shallow seas without navigation requirements this is typically around 50m to 55m
Span
Cost
Low elevation / shallow water
High elevation / deep water
Economic Comparison of First Penang Bridge
Based on prevailing costs and available technologies in July 1977
Source: The Penang Bridge, Planning Design and Construction by Tan Sri Datuk Professor Ir. Chin Fung Kee
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Asia’s first precast segmental bridge
Design & Build contract
Opened 1991
Kwun Tong Bypass Phase 2
Balanced cantilever segment erection
Completed project next to the old Kai Tak Airport Overhead gantry weighted 400 tonnes and was 130m long
15
Comparison between First and Second Penang
Penang Bridge (1985) 40m PC beam and slab
Second Penang Bridge (2013) 55m precast segmental box girders
Typical Cross Section
16m is enough for a three lane highway with full width breakdown land
Typically 10 – 16m Typically 10 – 16m
Precast Segmental Span by Span
19 Span by Span Erection
20
Erection Sequence
21 Erection Gantry
22
23
24 Srtuctural Completion
Precast Segmental Balanced
Cantilever
26 Why balanced cantilever?
Deep Bay Link
West Tsing Yi Viaducts
Span-by-span segmental
needs all of the segments in a
span to be simultaneously
supported by the gantry
Under some design
conditions this could lead to a
very expensive gantry:
- Long spans
- Tight radius curves
Shorter projects may not
justify investment
27 Shenzhen Western Corridor
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Total only ~ 4 ½ years
• Feasibility Study (incl. Conceptual Design & EIA) Aug 2001 – Sep 2002
• Detailed Design Jul 2002 – Jul 2003
• Construction (Gammon-Skanska-MBEC JV) Aug 2003 – Dec 2005 (28 months)
Fast Track Design & Construction
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30 Segment erection
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Cantilever tip derricks Segment delivery by barge
Segment storage Short line segment match casting
End Spans
Expansion joints are needed at regular intervals which interfere with balanced cantilever erection
Options - Short end spans – interrupt the rhythm of the bridge
- Temporary fixity of joints
- Mid span hinge
- SWC – hybrid solution
33 End span erection
34
Hong Kong Zhuhai Macau Bridge
• 43.6 km bridge over Pearl River Estuary
• 1st major combined bridge & tunnel
sea-crossing in China
• reduce travel time to 0.5 hour
from HK and Pearl River West
Macau
Zhuhai
HKSAR
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Lantau
Island
Macau
Zhuhai
Lantau Island
Qin
gzhou
navig
ation
channel
West Artificial
Island East Artificial
Island
Tunnel
HKBCF HK Section
36
37 Hong Kong Section
12km long highway
Including 9.4km sea crossing viaduct
38 Hong Kong Section
39
75m precast segmental balanced cantilever
Full Span Launching Method
41
42
Project Overview
Project Overview
43 Incheon Bridge
44
Full Span Launching Method
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Launching gantry
46 Full Span Casting Factory
47
48 Pretensioning
49 Erection of first segment
50
Delivery of segments in deep water which is accessible by floating crane
Transportation along the already erected deck by a mutli-wheeled transporter
51
Segment transportation is governing load
1,300 tonne segment and 950 tonne transporter unit
Spread onto four girders
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Erection equipment
Full Span Launching Method
Contractor was experienced with the method
Very long viaduct justifies investment in bespoke launching gantry to achieve very fast construction
No variations in deck width, no tight radius curves in highway alignment
Marine environment and availability of large capacity floating cranes
Low level viaduct makes moderate span length (50m) economical
Comparison of Sea Crossing
Construction Methods
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Project Second Penang
Bridge Incheon Bridge
Shenzhen
Western Corridor
Deck Type Precast Concrete Box Girder
Procurement
Method Design & Build Design & Build Engineers Design
Contractor UEM Builders Samsung
Construction JV
Gammon-Skanska-
MBEC Joint Venture
Construction Method Span by span
precast segmental
Full span precast
launching
Balanced cantilever
precast segmental
Status Under Construction Completed 2009 Completed 2006
Total Length 16.9 km 12.3 km 5.5 km
Viaduct Length 16.5 km 9.0 km 4.7 km
Width 2 x 14.0 m 2 x 15.7 m 12 x 16.05 m
Typical Span 55 m 50 m 75 m
Typical Bridge Unit
Length 330 m 250 m 590 m
Three sea crossings constructed in shallow water in East Asia
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8092 segments
3 lines of 7 moulds per line (different fabricators)
Storage capacity for 780 segments (2 months supply)
Typical segment – 1 per day
Second Penang Bridge Precast Yard
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360 segments
1 mould
Storage capacity for six segments (<2 weeks production)
One segment every 2 days
Incheon Bridge Precast Yard
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Casting yard in mainland China
1,879 segments
6 moulds
Segment casting started well in advance of erection
Shenzhen Western Corridor
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Project Second Penang
Bridge Incheon Bridge
Shenzhen
Western Corridor
Number of Spans 580 360 90
(Hong Kong section)
Number of Gantries 4 2
1 overhead gantry
+ 4 pairs of
cantilever derricks
Spans Per Gantry 145 180 16
Number of
Segments 8,092 360 1,879
Number of Moulds 3 x 7 = 21 1 6
Segments Per
Mould 385 360 313
Target Cycle Time 4 days per span per
gantry
2 days per span per
mould
1 week per span per
gantry
Theoretical Duration
at Target
Productivity
20 months 24 months 4.5 months
Three sea crossings constructed in shallow water in East Asia
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Second Penang Bridge
Design & Build – contractor can tailor method
Contractor had previous experience of span by span segmental
Environmental impacts acceptable with a 55m span
Incheon Bridge
Design & Build – contractor can tailor method
Contractor had previous experience of full span launching
Large number of spans justifies investment in bespoke gantry
Shenzhen Western Corridor
Very fast track project - needs multiple gantries
Limited number of spans – hard to justify bespoke investment
Engineers design – needs flexible method
Environmentally sensitive mud flats needs longer spans (75m)
ard
Conclusions
With constant width and gentle plan curvature a typical span length of
50m to 55m can be constructed by any one of the three methods
Speed of construction depends on number of construction fronts so the
cycle time for a single gantry may not dictate project duration
Span by span segmental construction is a versatile method but span is
limited to around 55m
Span by span segmental can be significantly accelerated if required once
construction team has gone through learning curve
Balanced cantilever will be more economical at longer spans
Full span launching will only be economical for very large projects which
tends to limit the number of contractors who will adopt it
Harder to accelerate full span launching
Emerging Trends
63 Stainless steel reinforcement
Extension of Design Life Asset Management
Structural Health Monitoring Threat and Vulnerability Assessment
Thank You