Installation methods:
Pre-cast (PC) piles can be installed utilizing a wide range of methods and each method has its own merits over the others. A simple method of installation is to use diesel, hydraulic or drop hammer but the method is not environmentally friendly not only that imposed load could damage the piles from time to time. An alternative method that is more environmentally friendly but not commonly available in Bangladesh or most other countries driving by static pressing. This method is widely used in Mainland China, Malaysia, Vietnam, India, Myanmar, Bangladesh & so many more countries. Static Pressing of PC piles:
- No noise pollution problem.
- No vibration.
- The load imposed on piles is minimized, and most critically, impulsive loading that is most damaging to the piles is eliminated.
- Highly automated process with minimal labour work requirement, the load and driving rete imposed can be monitored and recorded throughout the process.
- The work can be completed in a very short working period:
- larger drive capacity than any other driving system.
- 24 hours’ operation is feasible since the noise generated is insignificant.
- can operate in adverse weather condition.
- Applicable to some special ground conditions where pile hammer is not suitable.
- Effective driving
- Minimal wastage
- Easy to maintain pile geometry
- 10.Reduced overall construction cost.
Limitation of static pressing PC pile:
- Subject to influence from neighboring piles
- Not suitable for ground condition with underground cavity or underground.
Process:
The static pressing is rather simple. Firstly, PC pile insert inside the clamping box by the Hydraulic Crane. After accurate positioning of the pile, the equipment exerts pressure on the pile to drive the pile into the ground and the pile in going into the ground up the required label. Here interesting thing is to can see the pile pressure by pressure meter. Even you can calculate Metter wise pressure so, very simple calculation in every one can take every pile incle life history. A non-technical person cans simple calculation per pile & footing level capacity. We believe through the above discussion if a designer designs the pile length appropriately it may possible to reduce the length & size and it will be cost effectively. Successive sections of piles are welded together until the desired depth is achieved.
Methodology for the execution of RCC pre-cast pile driving work.
Static Pile driving procedure:
- Firstly move the machine to the job site by step moving mechanism (Horizontal, longitudinal and rotation).
- Secondly adjust the main body by vertical motion mechanism, and then hoist the PHC Into the clamping box.
- Thirdly hold the pile by clamping jaw and increase the pressure through the hydraulic Cylinders.
- The concrete pile will be pressed into the ground via the self-weight and the counter weight.
- When the static pressure overcomes the pressure piles in the pile side friction resistance and tip resistance, pile sinking into the soil along the buried direction.
Structure Hydraulic Static Pile Driver
Piling Platform
Piling platform is the main working body of the machine, which will achieve folder pile, piling operations. Consist of the pressure cylinder piles, beams, columns, clip pile boxes, folders pile cylinder etc.
Side Piling Equipment
If you want to handle corner or side pilling job, directly shift the main pressure cylinder assembly & clamping box assembly to the side pilling structure, then fix, installation, and connect the hydraulic tubing, thus can carry out the side/corner pilling job.
Lifting Mechanism
Lifting mechanism consists of four lifting cylinders and four cantilevers composition. Four cylinder lift cylinders were connected to the main machine by four cantilevers, and the piston rods articulated with the four walking cars, the adjustment of hoist cylinder will achieve the body movements. Pressure pile driver can walking and turning by the motion of lifting mechanism.
Crane
Crane is installed on JVY hydraulic static pile driver, and is mainly used for lifting the precast pile; it is an assistant equipment of pile driver. The structure of this crane is similar to hydraulic truck crane; consist of the boom hoist system, winch system, rotary system and hydraulic control system. Hydraulic control systems includes a manual multi-valve, control the corresponding multi-way valve and achieves the activities of amplitude, winding, rotary and telescoping, it can lift pile from 30-40 feet long distance & can lift 10 ton to 16 ton weight of a single pile etc.
Operation Principle of Crane
Hydraulic control system: The hydraulic pressure oil flow via rotary joint to crane system supplied by hydraulic pump. The system pressure is determined by overflow valve of multidirectional valve, the pressure setting is 18 Mpa. Hand operation can achieve the derricking, windlass, slewing and jib extending and retracting.
Pile Drop & drop level:
Each & every designer design the pile depends on the soil test. In the pre-cast Rcc pile driving using Hydraulic static pile driver the most important Thing is the screen fiction. During pile driving we can see pile pressure on the pressure meter of hydraulic static pile driver. When the pile pressure meter shows the sufficient pressure that matched with the designer design then we can assume that pile length is driven up to the save zone. At this point if we cut of the pile there will be not any problem.
Advantages of Hydraulic Static Pile Driver:
1) No noise pollution problem.
2) No vibration.
3) The load imposed on piles is minimized, and most critically, impulsive loading that is most damaging to the piles is eliminated.
4) Highly automated process with minimal labor work requirement, the load and driving rate imposed can be monitored and recorded throughout the process.
5) The work can be completed in a very short working period:
6) Larger drive capacity than any other driving system.
7) 24 hours’ operation is feasible since the noise generated is insignificant.
8) Can operate in adverse weather condition.
9) Applicable to some special ground conditions where pile hammer is not suitable.
10) Effective driving
11) Minimal wastage
12) Easy to maintain pile geometry
13) Reduced overall construction cost.