Purpose of this method statement is to define the fixing of the water stop in the sub structure concrete works as per the manufacturer’s requirements and drawings, considering all the necessary safety and quality aspects of the work activities.
Project manager shall ensure that the water stop works are carried out in accordance with company policies, approved methods & Project Quality Plan.
Site engineer and supervisors are responsible to ensure the full compliance of sub-contractors with the requirements of project requirements.
Foremen shall ensure that all the required equipment to execute the works according to the construction program are available, in good condition, and provide any additional equipment that might be required.
HSE engineer to co-ordinate with the Construction Manager, Project Engineer, Safety Engineer, Surveyor and Foreman for the safe and proper execution of the water stop works.
Tools & Materials
Arrange following tools before starting the water stop works.
- Superfast joining rig
- Knife
- Wire brush
- Welding Blade
- Supercast PVC
- Binding wire
Water Stop Installation/Fixing Procedure
Supercast Watafoil 250mm wide shall be used in raft at construction joints, in-fill strips, retaining walls, lift pits walls, manhole to raft connections.
All installation of Supercast PVC Water stop shall be in accordance to the manufacturer’s recommendations.
Lift Pit
The lift pit consists of three lifts of concrete: the pile cap/lift pit bottom, the lift pit walls and the connection to the raft.
The waterbar shall be installed in each of the construction joints. 250mm Supercast Watafoil shall be used in the wall lifts.
Manholes
Manhole shall be precast element that shall be placed in position, levelled, backfilled and ready for raft cast.
250mm Supercast Watafoil used in the manhole base and wall between the wall and the raft.
Note that in Stage 2 the wall ends below the raft bottom level to accommodate the raft reinforcement steel.
Raft & Retaining Wall
The raft shall be cast in sections and pour strips.
Following cases may be encountered:
Raft shown below is cast in the centre of the building as in the case of.
In such cases there are no retaining walls or edges to consider the waterbar used is 250mm wide Supercast Rearguard R.
For in-fill strips 250mm wide Supercast Rearguard R shall be used as shown below.
Retaining walls shall have waterbar as shown in figure.
Supercast Rearguard R, 250mm wide shall be used in raft at construction joints and in-fill strips.
Note that in the water tank wall waterbar is fixed at the top of the wall to be cast into the basement slab.
The same shall be the case for the retaining wall if the external ground level is above the joint or there is a green landscaped area above.
As shown below the Super Cast Rearguard R water stop shall be installed between retaining wall and water tank.
In retaining walls above Supercast Rearguard R shall also be used. Note that there is no water bar on top of the retaining wall shown below.
Water Stop in Expansion Joints
The expansion bars shall begin at the retaining wall above the raft. However, the water bar must be embedded in the raft. Before the cast of the raft concrete, retaining wall expansion joint locations shall be marked out by the surveyor and in these locations Supercast Rearguard S shall be fixed to the raft shutter.
The expansion joint shall continue in to the Ground Floor slab where it shall be treated as per approved method.
In areas of the ground floor expansion joint no water bar shall be used.
The expansion joint at this location shall only be treated by joint sealer as per waterproofing subcontractor’s approved method.
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