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620 CONSTRUCTION OF INTERMITTENT MASS CONCRETE UNDERPINNING/ UNDERPINNING
PIERS

• Block and working space: Excavate together. Excavated length not to exceed
design length by more than 75 mm.

• Formation:
- Preparation: Remove or compact loose material.
- Protection: Cover with 50 mm thickness of concrete if there will be a delay of
more than four hours between completion of excavation and casting of
concrete underpinning.

• Front shutter: Provide where required.
• Casting underpinning: In one lift, leaving a gap for packing up beneath existing

foundation.
• Packing: On completion of concrete curing period, hard pack gap between

underpinning block and existing foundation. Allow packing to cure before
commencing excavation for the next sequence of underpinning.

625 INSTALLATION OF RAKING PILES THROUGH WALL/ FOUNDATION
• Preparation: Break out concrete/ hard surfacing etc. and carefully excavate to
expose point of penetration into wall/ foundation.
• Permanent pile casing: Terminate at underside of foundation/ seating
enlargement.
• Condition of bottom of drilling and bonding faces of existing masonry/ concrete
prior to placing concrete: Clean.

640 INSTALLATION OF PILES WITH CANTILEVERED KNUCKLE
• Preparation: Carefully excavate to expose top of foundation. Break out wall and
foundation the minimum necessary to install pile and knuckle.
• Permanent pile casing: Terminate below knuckle.
• Reinforcement: Install in pile and knuckle before casting pile.
• Placing concrete/ grout:
- Sides of knuckle: Shutter.
- Condition of bottom of drilling and bonding faces of existing masonry/ concrete:
Clean.
• Completion of curing period: Hard pack gap between knuckle and existing wall/
foundation.

645 EASING PILE DRIVING
• Usage: Submit proposals and details of effects on pile bearing capacity.

660 INSTALLATION OF PILE PERMANENT CASING/ FRICTION REDUCERS
• Outer casing: Install to required depth using removable drill head/ shoe.
• Installing pile/ casing: Drive through outer casing.
• Other requirements: Not required.

665 INSTALLATION OF PILE FRICTION REDUCERS - DISPLACEMENT PILES
• Sleeve: Drill hole and install sleeve to required depth.
• Installing pile: Drive through sleeve.
• Grouting: Where required, fill between pile and sleeve, sleeve and ground.

RotF generic (intermediate) NBS 2014 6118-AEW-XX-XX-NBS-A-01