9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

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Preface• Thissectionistohighlightsomeofthoseareasthathavepotentialsafetyrisksinstructuralconstruction,

includingdemolition,foundationandbuildingworks.• Emphasiswillbeplacedonearlyplanning,designandspecificationprovisions.

DemolitionDemolition Plan• DemolitionplanispreparedearlybytheStructuralEngineerincorporatingallcriticalsafetyprovisions.• Theseplansaretobeincorporatedintotenderdocuments.• Whenthecontractisawarded,theContractorisrequiredtosubmittheirproposeddemolitionplanwhich

shouldbeinlinewiththeSE’sdemolitionplan

Demolition Planning Features

Double deck hoarding / covered walkway to protect pedestrians; locations and extent of hoarding should be clearly defined

Scaffold, nylon mesh and periphery catch platforms / fans to prevent demolished debris from falling out of the block

The route for movement of mechanical breaker must be defined in Demolition Plan. Adequate propping should be provided underneath

Stacking of demolished debris not to exceed allowable height. Debris is to be cleared from time to time

Barrier erected at the opening of refuse chute. Scaffold and nylon mesh at the building perimeter must be more than 1 meter height

Clamping instead of tack welding to bracing should be specified in Demolition Plan; tack welding is difficult to assess for adequacy

Presenter:MrJosephMAK(HD)

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Early identification of asbestos containing materials by asbestos consultant

Asbestos Handling• Asbestosremovalshouldbewellplanned.• Theseinclude: - Earlyidentificationofpossibleasbestoscontainingmaterialsbyasbestosconsultantbeforetender. - RequirementsforasbestosremovalspecialistcontractorstipulatedinSpecification.

Identification of Asbestos Containing Materials

Asbestos Removal Works

Asbestos removal works for fuse box

Asbestos removal works for grille panel

Chalk board covered by polythene sheet

Vacuum cleaner with HEPA filter

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

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Sealed drum

Respiratory protective equipment and protective clothing used for asbestos abatement work

Transferring sealed drum to the ground

Spray of water

Asbestos particles removing

Compartment for Asbestos Removal Works

Passage for Asbestos Removal Works

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Plan

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Designated asbestos sorting area

Transportation of sealed container to designated chemical dumping site

FoundationExcavation and Lateral Support (ELS) Works• Forlargescaleexcavationandlateralsupport(ELS)works,itisimportantthatStructuralEngineershould

designapretenderscheme.• TheschemewouldbeusedasabaseforcomparingwithContractor’sproposedschemeattenderreturn.• ThisallowstheSEtobetterassessthestructuraladequacyofContractor’sproposedscheme,aswellasthe

correctorderoftheELScost.

Engineer’s ELS Scheme at Pretender Stage

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Contractor’s ELS Scheme

ELS Works

Materials and Plant Handling• Safetyinmaterialandplanthandlingisoftencriticalinfoundationcontracts.• EarlyplanningbycontractorandcheckedbySEinmaterialsstorage,manoeuveringofplants, transportingofheavyandlargevolumeofmaterialsareessential.

Materials Storage

Proper storage of H-pile material

Store rack for RCD drill rod

Proper storage of steel casing

Proper storage of steel liner

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Plan

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Equipment Disposition and Transportation

CCTV in operator cabin

Warning bar & rear camera

Overload alarm of excavator

Lifting steel cage by 2 cranes (horizontal)

Lifting steel cage (vertical)

Overload alarm

Lifting casing (horizontal)

Lifting steel casing (vertical)

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Loading Test

BuildingLarge Steel Cage Erection in Pile Cap and Transfer Structures Large Steel Cage Erection in Raft Footing for Domestic Blocks

Large Steel Cage Erection in Raft Footing for Domestic Blocks(Shear Links not Required)

Large Steel Cage Erection in Raft Footing for Domestic Blocks(Shear Links Required)

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Final set up of mass steel kentledge

Less congested shear links

Typical RC Detailing – Minimization of shear links by new design approach

Typical concrete block kentledge

Congested shear links

Congestion of shear links can be mitigated by enlargement of member size

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Passage through Falsework

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Steel Fixing and Concreting at Heights

Adequate lighting and fencing off hazardous area

The upward projections of congested shear links pose safety concerns during fixing of the upper layers of the reinforcement bars

Bad example

Bad example

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

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Temporary working platform provided for concrete pouring at heights (below 2m)

Mobile working platform (above 2m)

Bad Examples

Working platforms suggested in COP

Working platform with adequate railings and toe boards was provided during working at heights

Good housekeeping in working area

Working platform provided for steel fixing works at heights (above 2m)

Working chair provided for steel fixing works at heights (below 2m)

Mobile working platforms for steel fixing or concrete pouring suggested in COP

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

By Use of Fabric Reinforcement at Walls

Mechanized and Precast Construction for Elevated StructuresBenefit of Rotary Symmetry

Large Panel Formwork

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Traditional rebar fixing

Ideally design block with rotary symmetry to avoid moving formwork to ground level

If rotary symmetry cannot be fully achieved, designated site crews should be assigned to look after every movement of formwork to ground level.

Fixing of fabric reinforcement

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Precast Facade

Precast Staircase

Semi-precast Slab

Precast Beam

Precast staircase is supported on concrete landing cast earlier so that temporary props are not required. Temporary props may be easily disturbed due to frequent passage of workers.

Avoid slab formwork construction and minimize nos. of proppings

Avoid insitu construction of tie beams at elevated positions

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Allow enclosed working floor for other construction

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Crane HandlingTower Crane, Material Hoist, CCTV and Double Chain Sling

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Tower crane CCTV, monitor and control panel

Lifting zones are identified during site planning stage maximum required lifting weight for the precast elements has been considered in the selection of crane system & jib length as well as in the location of tower cranes

Overlapping areas and sensitive areas were identified during site planning stage anti-collision system were installed to all cranes

Material hoist CCTV and recording

New design double chain sling for lifting of hopper

Walkie-talkie is provided for signaler

Traditional single chain sling

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9. Safety through Early System Planning and Structural Design Approach for Demolition, Foundation and Building Contracts

We care about people. We care about life. With concerted efforts, we strive to raise safety awareness and foster occupational safety.

Gondolas

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Previous arrangement –Two supports for one gondola holding down / fixing to roof floor

A close-up view of the hole for tying wire

Current proposed design –Two supports for one gondola tying to roof parapet

Conclusion• Safetyresponsibilitydoesnotrestwiththeworkersandsitesupervisorsalone.Itwouldbemoreeffectiveif

thesafetyDNAbeearlybuiltinthedesignandmanagementlevels.• Atdesignlevels,ifstructuralcomponentsincludingbothpermanentandtemporarydesignsarewell

consideredandadequatelyallowed,itwouldremovesignificantsafetyrisksforworkerscarryingouttheconstruction.

• Atmanagementlevels,ifconstructionmethodologyandplantandequipmentcontrolandhousekeepingarewellplannedandproperlymanaged,thehighsafetyriskstoworkersoperatingthesesystemscouldbemuchreduced.

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