Pilling was carried out by hydraulic rigs. Two types of piles were used to build a firm foundation for the 4.4 km. Elevated Highway i.e. friction piles with a 1,200 mm. diameter and end bearing piles with a 1,500 mm diametre.
Process of Pilling Work
- Coordination of the piles was calculated from alignment drawings and marked with precise surveying equipment at the pier location
- The pilling rig was brought into position to bore the pile
- All loose material and muck was removed using Bentonite Slurry Flushing
- The reinforcement cage was lowered into the bored pile and then the trimmie pipe was lowered.
- Concreting was done in a way that ensured no slurry or voids remained while concreting the pile cap.
: In order to transfer load safely onto the piles, the pile cap was provided at the top of the Group of Piles.
Process of Pile Cap Casting
Pier & Pier Cap
- Excavation below ground as per the dimensions of the pile cap
- Cutting of a 0.7 m pile head
- Providing a PCC course to create a firm platform
- Providing reinforcement as per the design & drawing of the pile cap
- Erection of the shuttering & supporting platform to carry concreting
- Concreting of the pile cap
: The pier and pier cap were provided to transfer the load of the superstructure to the foundation. Special moulds were fabricated to case the pier & pier cap monolithically, which reduced the time cycle by up to 4 days.
Process of Pier Casting:-
- Reinforcement was provided as per the design & drawing
- The shutting/mould was erected as per the required height of the pier
- The pier start-up of around 100 – 500 mm. was cast to match the shutter as per the required height
- The remaining height of the pier and pier cap was cast in a single pore with the help of the boom placer
- After gaining sufficient strength, the mould was removed
:The innovative shutter design was implemented for both the pier and pier cap, which made it possible to cast both in one pour. This type of self-supporting shutter decreased the cycle time from 15 days to 3 days, which in turn led to early completion of the project. This process also left the cast piers with a slim design and provided for wonderful aesthetics.