Launching Bridges in to the Future. CBDG Annual Conference. Simon Bourne Managing Director. 26 June 2008

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1 Launching Bridges in to the Future CBDG Annual Conference 26 June 2008 Simon Bourne Managing Director

2 Use of Incremental Launching Deck lengths of more than 200m 30-70m spans, typically regular 45m spans Constant depth at L/h~16 Single-cell boxes best Steel moulds to cast ~25m per week Steel launching nose Pushed or pulled over low-friction surfaces Straight cables or RC for launching Profiled cables for continuity See CBDG Current Practice Sheet No. 13 for more details

3 Evolution - Incremental Launching Sungai Sitiawan Bridge 650m long bridge over Sungai Sitiawan classic 45m spans, internal prestress Broadmeadow Estuary Bridge 310m long bridge over estuary and bird sanctuary 69m spans, props, RC and external prestress Blackwater Viaduct 450m long bridge over River Blackwater 58m spans, props, RC and external prestress Kincardine Bridge 1,190m long bridge over Firth of Forth 45m spans, external prestress

4 Classic Launching - Sungai Sitiawan 45m spans Constant 2.9m depth No temporary props 30m long steel nose Straight, internal cables for launching Profiled, internal cables for continuity Fully prestressed and fully compressed

5 Sungai Sitiawan Bridge Launching nose

6 Internal launching prestress

7 Sungai Tebok Raja Samalon Bridge

8 First Evolution of Launching - Broadmeadow 69m spans Constant 2.9m depth Temporary midspan props 25m long steel nose RC section only for launching - design to crack widths Profiled, external cables for continuity - 310m long Partially prestressed in service

9 Broadmeadow Estuary Bridge Temporary props and nose

10 External continuity cables and deviators at third points

11 External continuity cables

12 Broadmeadow Estuary Bridge

13 Broadmeadow Estuary Bridge

14 Second Evolution of Launching - Blackwater 58m spans Constant 2.9m depth Temporary midspan props 20m long steel nose RC section only for launching - design to crack widths Profiled, external cables for continuity 450m long, low-friction VBT cables Cables anchored only at the abutments Partially prestressed in service

15 Blackwater Viaduct Blackwater Viaduct Temporary props and nose

16 Temporary props and nose

17 External continuity cables and deviators at third points

18 External continuity cables

19 Blackwater Viaduct

20 Third Evolution of Launching - Kincardine 45m spans typically Constant 2.8m depth over 1,190m No temporary props on marine 45m spans 35m long steel nose Straight, external cables for launching - 2 spans long Profiled, external cables for continuity - 3 spans long Partially prestressed and designed to mm crack widths Fully compressed under permanent loads Loads shared between prestress and rebar

21 Kincardine Bridge Launching nose and single marine piers

22 Launching nose attachment

23 125m long casting area with two skidding beams on vertical CFA piles

24 1,200t pushing jacks 32,500t deck

25 Pier top and soffit integration to suit launching

26 GRAVEL LAUNCH 1.2MN MHWL MLWL SOFT CLAY GLACIAL GRAVELLY CLAY SANDSTONE L A U N C H I N G PILE / PIER MOMENTS MUDSTONE SANDSTONE Single 3m diameter bored piles in rock sockets

27 1% rebar in pile cage sized under launching Permanent steel casings

28 225mm slabs and 400mm webs with Grade 60 concrete

29 3.5m long diaphragm unit with launching and continuity cables

30 Continuity cables and deviators at third points C O N T I N U I T Y C A B L E

31 Kincardine Bridge

32 Fourth Evolution of Launching - Modular Bridges 15-50m spans Constant depths of 1-3m 2.5m long precast shells match-cast off site Assembled and infilled with concrete on site Straight, internal cables for launching Temporary props possible Steel nose Profiled, internal cables for continuity Fully prestressed

33 Objectives Serious competitor to steel-composite and precast beam schemes More elegant and efficient than steel-composite or precast beams Covers all standard highway locations Covers variable depths, spans and widths Launching technology to avoid working at height over the road

34 Evolution - Precast Shells Taney Road Bridge 110m main span cable-stayed bridge Alternative precast shell solution Quicker erection over road junction Easier stressing operations River Shannon Bridge 150m long 5-span bridge Alternative precast shell solution Quicker and easier construction

35 Taney Road Bridge Precast shells

36 Taney Road Bridge

37 River Shannon Bridge Precast shells

38 River Shannon Bridge

39 Key Features Speed of construction is the key to value Match-cast off site for safety, quality and speed Elimination of box forms easier moulds Shell structure to provide the soffit form Internal prestressing in infill with continuous ducts to TR47 Pre-assembly behind abutment for safety and quality Launched in to place for safety, ease and less traffic disruption Props may be used to reduce prestress Robust, simple, clean lines for low maintenance

40 Typical Midspan Section PRECAST EDGE UNIT INSITU INFILL CONCRETE C L 2 No 19/15mm LAUNCH CABLES 6 No 19/15mm PROFILE CABLES TEMPORARY PRESTRESSING BARS - 2No 32 DIA. PRECAST CONCRETE SHELL

41 Typical Construction Sequence 1 PACK UNITS AND ALIGN FORM JOINTS TEMPORARY STRESS 2 POUR INFILL CONCRETE STRESS LAUNCH CABLES ATTACH NOSE 3 LAUNCH OVER PROPS PACK UNITS AND ALIGN FORM JOINTS TEMPORARY STRESS TEMPORARY PIERS & FOUNDATIONS TEMPORARY PIERS & FOUNDATIONS

42 Typical Construction Sequence 4 POUR INFILL CONCRETE COUPLE LAUNCH CABLES STRESS LAUNCH CABLES TEMPORARY PIERS & FOUNDATIONS TEMPORARY PIERS & FOUNDATIONS 5 COMPLETE LAUNCH TEMPORARY PIERS & FOUNDATIONS TEMPORARY PIERS & FOUNDATIONS 6 REMOVE NOSE CAST MONOLITHIC PIER TOPS STRESS PROFILED CABLES REMOVE PROPS

43 Typical Three-Span Bridge

44 Options for Varying Spans PROFILED PIER CABLES LAUNCH CABLES PROFILED SPAN CABLES MINIMUM SECTION: SPANS 15-25m LC IN-SITU STITCH IN-SITU INFILL TYPICAL SECTION: SPANS 25-35m LC PRECAST UNITS MAXIMUM SECTION: SPANS 35-50m

45 Options for Varying Widths LC NARROW DECK: 9m 1500 LC 5000 NO. OF BEAMS OVERALL DECK WIDTH (m) TYPICAL DECK WIDTH: 11.5m C L 6000 WIDE DECK: 14m

46 Typical precast shell unit

47 Typical three-span bridge

48 Typical soffit appearance

49 Typical soffit appearance

51 Launching Bridges in to the Future High-quality concrete Factory-controlled conditions Safer and faster construction Minimises traffic disruption Integration of design and construction is key Low maintenance structures New innovations always developing See CBDG Current Practice Sheet 13 for more details See CBDG Technical Guide 12, Guide to Modular Bridge Construction - due out soon

52 Launching Bridges in to the Future

Concrete Bridge Design and Construction series

www.thestructuralengineer.org 41 CBDC series July 2014 Concrete Bridge Design and Construction series This series is authored by the Concrete Bridge Development Group (CBDG). The group aims to promote