Friday, August 16, 2013


Stage 1.
1.       Before proceed with any works, survey and setting out shall be conducted to 
       provide the guide on levels and alignment for the construction of the Reinforce 
       concrete Retaining Walls.
2.       Survey and setting out shall be done in the present of Resident Engineer or his 
3.       Request for inspection shall be submitted prior to start the works.

Stage 2.: Earthworks (Excavation)
1.       Earthworks can only commence after the setting out was done and accepted by 
       Resident Engineer.
2.       The sequence of the Earthworks is as the following Diagram 1.

Diagram 1.

3.       The excavation at Sequence 1 will be done until it reaches the proposed platform level 
       where it will provide wider temporary diversion during the construction of the Retaining
       wall structure.
4.       The excavation work at sequence 2 will only commence after the completion of sequence 1.
5.       The sequence 2 will provide access for existing traffic during the excavation work 
       activities at sequence 1.
6.       The Layout after completion of earthworks activities for both sequences will be as the 
       following Diagram 2.

 Diagram 2

Stage 3: Construction of RC Retaining Wall Structure.

Level  1: Piling Works
1.       Piling works will commence after the completion of first half of the sequence 2 
2.       The sequence of the piling works will be done starting form the end Chainage 
       of the Retaining wall progressing to the front Chainage.
3.       The excess of drive R.C pile will be cut as soon as the Piling works reaches 
       practical numbers of piling points to enable the pile cut off activities.

Level 2 : construction of the R.C Retaining wall Base.
1.       The construction of the base will commence as soon as after the preparation of the
       pile head reaches the practical length of the standard steel bar supply length or 
       available safe working area. (eg. Standard steel bar supply length / pcs = 12m )
2.       All of the installed reinforcement must be free from rust, properly tied and being 
      installed according to construction drawings and specifications.

Level 3: Concreting works.
1.       Concreting works will only commence after the installed reinforcement being 
       inspected and accepted and approved for next sequence of works by Resident Engineer 
      or his or her representative.
2.       The sequence of concreting activities will also start from the end chainage of the R.C 
      Retaining Wall base.
3.       Concreting works will commence as soon as the installed reinforcement for the base 
      reaches the possible delivery concrete volume to site per day and practical output of
      the concreting works.
4.       Prior to concreting activities, all installed formworks for the base shall be properly secure 
      to avoid formwork failure.
5.       During concreting activities, test cube and numbers of the cube to be prepared shall be 
      as per directed by Resident engineer or his or her representative.
6.       There shall be no concreting activities during raining day.
7.       The flow of the installation of the reinforcements and concreting activities shall be as 
       per diagram 3.

Diagram 3

Level 4: Construction or R.C Wall.
1.       The construction of the R.C concrete wall shall proceed as soon as the Concreted base 
       is ready to accept the next sequence of the works.
2.       Construction of the wall shall start for both side of the retaining wall concurrently. 
      However some section of the wall might need to be left open to suite the site condition and 
      the movement of machineries.
3.       R.C wall construction activities shall start from end chainage of the retaining wall.
4.       The height of each wall that is ready for concreting shall not exceed 2.4 meter high. This is 
       to avoid the formwork failure.
5.       Prior to fully erect the formwork, wall reinforcement must be inspecting by Resident engineer 
       or his representative for acceptance and approval for next sequence of work.
6.       Prior to concreting activities formwork shall be properly secured to avoid formwork failure 
      during concreting activities.
7.      There shall be no concreting activities conducted during raining day.

8.       Flow of the R.C Wall Construction is as shown in the following Diagram 4.

Diagram 4

Stage 4: Backfilling to completed Retaining Wall.
1.       Backfilling activities will commence as soon as the fully completed section of the 
      retaining wall is ready to received backfill material and also practically safe for the 
      other on-going construction activities for remaining Retaining wall structure.
2.       Each layer of backfill shall be not more than 500mm thick and shall be properly 
      compacted before laying of subsequence layer of backfill. This process is repeated 
      until the whole height of the retaining wall if filled.
3.       Backfill activities will commence from the end chainage of the retaining wall towards
     the CH 6 + 200.

Stage 5: Miscellaneous works.
1.       Miscellaneous works will commence upon completion of the whole retaining wall 
      structure inclusive of backfilling works.
2.       The miscellaneous works are the flexible pavement, drains and  road furniture.

Overall sequence of the stages:

1 comment:

  1. Information is helpful. Suggest the particular problem situation is mentioned first; for example To avoid rocks falling from the hill side along road X leading to Town Y a RC concrete RW is suggested. The adjacent road is x m wide with dual lanes with shoulders on a flat land area on the opposite side of the hill. etc.
    The proposed RW is a cantilever RW with base 5m and depth 1.2m . Height 9.5m etc. etc. A method statement for the construction of the RC RW is to be written for the review of the Resident Engineer.