PILE DRIVING METHOD
1) The crane barge is set up at the first pile location and heading in-line with the mooring chain leg to be installed in order for the pile pad eye to be orientated in line with the chain leg and center of mooring.
2) The pile transportation barge is temporarily moored on the side of the crane barge.
3) The subsea frame is lowered on the sea bed, with the center at the pile target coordinates, and center of slot in line with the proposed chain. The frame will be orientated and centered as required by DGPS or the pile orientation with subsea gyro attached with a surface read out.The level of the subsea frame will be confirmed by diver and/or ROV depth sensor at the 4 corners of the mudmat. An onsite decision on which method to be used has to be decided after consultation with the Class/MWS representatives onboard.
4) The pile is lifted and brought to the installation side of the barge. The chain is then connected to the pile mooring lug after which the pile will be lowered and set into the pile stabilization frame. The orientation of the pile is maintained by the two orientation plates installed at the required positions on the pile sides which are inter locked in guides on the stabilization frame. The pile orientation will be monitored by divers and/or ROV before it is lowered to full self penetration by matching the white line marking on the pile which will be aligned with the orientation markings on the pile frame. Once the pile orientation is confirmed , the pile will self-penetrate with its own weight. A re-check of verticality and orientation will be performed after self-penetration has been achieved.
After the pile has self-penetrated, the chain is lower so that there is enough slack. The ILT is then disconnected from the pile and recovered to deck.
5) The hammer is lifted and pre-positioned on the surface above the pile target and then lowered over the pile. ROV will monitor and guide the stabbing of the hammer on the pile top to prevent any side loads to the pile.The barge moorings will be adjusted during all stabbing and pile driving activities, as necessary depending mainly on the changing environmental conditions.
Before the hammer is activated, the chain catenary will be monitored by the ROV and a sufficient amount of chain will be lowered as required to allow the pile to be driven to final penetration. The chain is now secured on the chain barge with chain stoppers and all the tension on the chain payout winch is released.
6) The hammer starts to drive the pile and the chain is paid out as needed. The pile is now driven until its top is at about 1m above the mud level, ROV to assist and monitor the marks on the pile until the pile is driven to design penetration. The hammer is finally recovered.
7) Finally a chaser pile can be used together with the hammer in order to get the pile driven to the design depth.
1) The crane barge is set up at the first pile location and heading in-line with the mooring chain leg to be installed in order for the pile pad eye to be orientated in line with the chain leg and center of mooring.
2) The pile transportation barge is temporarily moored on the side of the crane barge.
3) The subsea frame is lowered on the sea bed, with the center at the pile target coordinates, and center of slot in line with the proposed chain. The frame will be orientated and centered as required by DGPS or the pile orientation with subsea gyro attached with a surface read out.The level of the subsea frame will be confirmed by diver and/or ROV depth sensor at the 4 corners of the mudmat. An onsite decision on which method to be used has to be decided after consultation with the Class/MWS representatives onboard.
4) The pile is lifted and brought to the installation side of the barge. The chain is then connected to the pile mooring lug after which the pile will be lowered and set into the pile stabilization frame. The orientation of the pile is maintained by the two orientation plates installed at the required positions on the pile sides which are inter locked in guides on the stabilization frame. The pile orientation will be monitored by divers and/or ROV before it is lowered to full self penetration by matching the white line marking on the pile which will be aligned with the orientation markings on the pile frame. Once the pile orientation is confirmed , the pile will self-penetrate with its own weight. A re-check of verticality and orientation will be performed after self-penetration has been achieved.
After the pile has self-penetrated, the chain is lower so that there is enough slack. The ILT is then disconnected from the pile and recovered to deck.
5) The hammer is lifted and pre-positioned on the surface above the pile target and then lowered over the pile. ROV will monitor and guide the stabbing of the hammer on the pile top to prevent any side loads to the pile.The barge moorings will be adjusted during all stabbing and pile driving activities, as necessary depending mainly on the changing environmental conditions.
Before the hammer is activated, the chain catenary will be monitored by the ROV and a sufficient amount of chain will be lowered as required to allow the pile to be driven to final penetration. The chain is now secured on the chain barge with chain stoppers and all the tension on the chain payout winch is released.
6) The hammer starts to drive the pile and the chain is paid out as needed. The pile is now driven until its top is at about 1m above the mud level, ROV to assist and monitor the marks on the pile until the pile is driven to design penetration. The hammer is finally recovered.
7) Finally a chaser pile can be used together with the hammer in order to get the pile driven to the design depth.
