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Tsinghau LectureDesign for Safety
Ian Askew, General Manager Lambeth Associates
10 May 2012
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Fatality statistics by region
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“Challenge traditional thinking in roles and responsibilities of project stakeholders…”
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‘Hazards leading to 60% of construction accidents could have been designed-out’
Designers….do not underestimate your input to safer construction
(ref. European Foundation for the Improvement in Living and Working Conditions)
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Maximize open excavation
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Maximize working space
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not like this….
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or this….
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or this….
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Standardize…make it repetitive …keep it simple!
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Engineer-out, as far as possible, need for workers to enter deep excavations
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The Challenge©
200
4 G
amm
on C
onst
ruct
ion
Lim
ited
. A
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Marina Bay in the 1950’s
Rock Armour up to 8T
Existing Seawall
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Designing out risk….deep excavations Cofferdam
Dredge
N
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Soil Conditions
Fill
Marine Clay
Old Alluvium (N value > 100)
Existing Ground Level+105
(m)
+100
+90
+80
+70
+60
Seawall
+50
Kallang Alluvial
Marine Clay
60 - 80m
40m
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Typical Cofferdam Wall Arrangement
1.8m & 1.5m Dia. Steel Casing
+80mPD
2.1m
Top of Old Alluvium
Excavation Face
+84mPDExcavation level
Sheetpile & TAM Pipes
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Removal Method – Stage 1
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Removal Method – Stage 2
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Removal Method – Stage 3
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Removal Method – Stage 4
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Excavation Method – Stage 5
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Redundancy for the case of one strut failure
Moveable deflection panels to be provided during grab operation for added protection
Strutting designed for an impact force of 25kN
Protection barrier
Design-in robustness
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Maximize offsite prefabrication of support elements…modularize
Fabrication of Megatruss Struts
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Campaign feedback from frontline workers on buildability
Waling Detail (Improved for Demolition)
Waling Detail (Before)
Strut
Void former
Concrete waling Concrete fill Concrete fill
Concrete waling
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Designing out risk….we need fresh thinking!!
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Designing out risk….make it less labour intensive
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Designing out risk….make it less labour intensive
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Designing out risk….make it less labour intensive
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Designing out risk….make it less labour intensive
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Communicating design intent……
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Isometric views
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Isometric views
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Harnessing technology….BIM
Hennessy Centre, Hong Kong
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and….Google Sketch-up….WIL 704
Hennessy Centre, Hong Kong
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and….Google Sketch-up…Austin Station
Hennessy Centre, Hong Kong
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….QR codes..design drawings to 3-D visualizations
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To avoid this….
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and this….
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Work procedure drawings• pictorial and illustrative
in a language workers understand at a glance
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Work procedure drawings• each sequential step
in the erection and dismantling process
• hold points where validation, testing, and/or certification of the erected structure to take up load or to undergo a change in loading is required
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…Pictorial method statements
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…Pictorial method statements
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Identifying residual risks
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Worker access and egress
Steel Post
Top Railing
Kick Board
TemporaryShoring
Diaphragm Wall
TemporaryStaircase
Steel Bracket
Waling
Struts
Concrete Packing
TemporaryWalkway
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Managing field changes
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Managing field changes
As-BuiltOriginal Design
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Temporary works control
• enforcing temporary works procedures
• improving traceability and transparency
• encouraging communication between design and construction team
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The objective …….