[FONT='Times New Roman','serif']1. [/FONT][FONT='Times New Roman','serif']Introduction[/FONT]


The purpose of this document is to describe in detail the operations and sequence of activities pertaining to the installation of circular steel piles as part of the construction activities for the eastern and southern suspended quay.
In order to illustrate the procedures associated with the piling works, pile ‘B23’ will be used as a case study throughout this document

2. Related Documents

Piling works shall be carried out in accordance with the documents:



3.0 Definitions

3.1 Temporary casing: This is a 915 mm O.D. steel pipe with 20mm wall thickness. Its length varies from one pile to another depending on the seabed level.
3.2 Temporary Casing Leader: This is a 95 cm O.D., 3 m length circular steel pipe with 10mm wall thickness used to guide the auger of the drilling rig during predrilling and ensures the verticality and accurate positioning of the temporary casing while being driven into the temporary platform using the vibratory hammer.

3.3 Leader Concrete Block: This is a 200×200×60 cm concrete block with a cylindrical shaped box-out 60 cm high and 97 cm diameter at its centre through which the temporary casing leader is driven into the temporary platform material. The block is used as a dead weight to prevent lateral movement of the temporary casing leader while being driven using the vibratory hammer and hence ensuring its accurate positioning and verticality as well as the temporary casing.
3.4 Rock Socket: This is the cylindrical shaped hole resulting from drilling into the sea bed rock. Its bottom level is the bottom of excavation for the pile and its diameter is 800mm which is the O.D. of the rock auger.
4.0 Equipment.
The following plant and equipment will be used in the piling works:
1.BAUER BG14 drilling rig
2.HITACHI 230-3, 65 ton crawler crane
3.HYUNDAI R320 LC-7 crawler excavator
4.HYUNDAI HL 760-7 wheel loader
5.ICE 416 vibratory hammer with hydraulic clamp and power pack
6.MERCEDES prime mover with low bed trailer
7. MEV CASTORO dry batching plant 70 m3/hr with 2 no. 100 ton cement silos
8.L&T 7m3 transit mixer on 3824 Mercedes truck

5.0 Detailed Piling Method and Sequence.

5.1 Setting out the centre point of the pile
5.2 Excavating for the leader concrete block to a depth of about 70 cm. from the top of the platform.


5.3 Marking the centre point of the pile on the bottom of excavation and then levelling it using 10mm aggregate.
5.4 Transporting and placing the leader concrete block so that its centre matches the centre point of the pile .

5.5 Backfilling around the leader concrete block and then placing the temporary casing leader in position inside the leader concrete block.
5.6 Driving the temporary casing leader into the temporary platform material using the vibratory hammer so that its bottom is about 3 metres below the top of the leader concrete block .
5.7 Predrilling into the temporary platform material down to the bottom of the temporary casing leader using BG14 drilling rig in preparation for driving the temporary casing.
5.8 Transporting and lowering the temporary casing into the temporary casing leader and then driving it down using the vibratory hammer so that a penetration of about 0.5 metres into the bedrock is achieved. For any given pile, the length of the temporary casing should be such that its top is about 1m above the top of the temporary piling platform (+2.5m ACD) and its bottom 0.5 m into the seabed. In the case of pile B23, and by referring to drawing Nr. 1802-3001 sht. 1/1 rev.6, the sea bed level is at –5.6m and therefore the length of the temporary casing to be used is 9.6 m .
5.9 Extracting the temporary casing leader and then removing the leader concrete block using the HITACHI 65 ton crawler crane and levelling the area around the temporary casing in preparation for drilling .


5.10 Drilling into the bedrock using the BG14 drilling rig down to the required level of bottom of drilling for the pile, which is the design bottom of pile and an additional 0.5m of drilling so that the permanent pile is resting on concrete. The design bottom of drilling is determined by referring to the table in drawing Nr. 1801-3401 sht. 2/3 rev.A and sections B, C in drawing 1801-3400 sht. 3/4 rev.A. In the case of pile B23, the top of pile level is +1.628m and the pile length is 12.5m and hence bottom of pile level is –10.872m, which makes the bottom of drilling level –11.372 .


5.11 Cleaning the rock socket prior to tremie concreting using BG14 drilling rig.
5.12 Assembling the sections of the tremie pipe using the HITACHI 65 ton crane. The total length of the tremie pipe is ideally equal to the distance between the bottom of pile level and the top of the temporary casing. In the case of pile B23, the length of the tremie pipe should be approximately 14m.
5.13 Lowering the tremie pipe through the temporary casing into the rock socket so that its bottom is approximately 0.3m above the bottom of the rock socket as shown in figure (6) below.
5.14 Transporting the required quantity of concrete for the pile from the batching plant to work site using the L&T Mercedes transit mixer and starting tremie concreting until the required top of concrete level is attained. In the case of pile B23, and by referring to the table in drawing Nr. 1801-3401 sht.2/3 Rev.A, the embedment length of the pile is 4m, which makes the top of concrete level inside the rock socket at –6.872m .
5.15 Transporting the steel pile required from the fabrication yard to the piling works site. The length and wall thickness of the pile should be as per the table in drawing 1801-3401 sht. 2/3, Rev.A. In the case of pile B23, the wall thickness is 15.875mm and the pile length is 12.5m. (N.B. site practice will be to use nominal lengths of piles supplied by the manufacturer i.e. 13.15m or 16.15m to be cut after installation to the correct top of pile level.)
5.16 Lowering the steel pile using the HITACHI 65 ton crane through the temporary casing and into the concrete in the rock socket until the bottom of pile level is in accordance with the design bottom of pile level . In the process, the verticality of the pile must be maintained and spacers between the steel pile and temporary casing used to ensure accurate positioning of the pile.

5.17 Securing the pile in its final position by hanging it on the temporary casing using tie rods.
5.18 Twelve hours after the concreting time, the temporary casing is fully extracted.