Method Statement for SURVEYING AND SETTING OUT
SURVEYING AND SETTING OUT
1.0 OBJECTIVE:
1.1 Is to define the procedure for surveying and setting out works for the contract no GTC.101/ED/01 Engineering, Procurement, Installation and Commissioning (EPIC) of Ras Laffan Utilization Project –Buildings and utilities and support service Phase 1-Utilities.
2.0 SCOPE:
2.1 Applicable to all buildings and utilities at Base Area, New Service Berth in Berth Area, FSO Marine and Telecom building.
3.0 REFERENCE:
3.1 Project Approved Drawings
3.2 Qatar National Height Datum reference level
3.3 Qatar Petroleum Standard Specification for Civil Works Vol. 1, Sect. 1.6-1.9
3.4 Qatar Construction Spec. sect. 1 part 13
4.0 PROCEDURE:
4.1 ESTABLISHMENT OF TBM
4.1.1 It includes location the existing services, surveying the site and establishment of temporary Bench Marks. The levels of the TBM should be related to the Qatar National Height Datum (QNHD). An existing BM or control station related to the QNHD will be indicated by QP Engineer for the purpose.
4.1.2 The contractor shall prepare a plan detailing the location of the benchmarks and TBMs and keep it up to date for the duration of the contract.
4.1.3 The contractor shall protect and maintain the TBMs until the works are complete. Upon completion of the work the contractor shall clear away the TBMs to the satisfaction of QP engineer.
4.1.4 The contractor is responsible for checking the accuracy of the TBMs. Request for Inspection shall be submitted to QP engineer to verify the same.
4.2 SURVEY INSTRUMENTS:
4.2.1 Before commencement of any survey works, the contractor shall ensure the accuracy of all Instruments used including the validity of calibration certificates. Trial readings/survey shall be performed between known points to verify the accuracy of the instrument.
4.2.2 If the trial readings are found accurate, the instrument can be used on works. If any errors found in the instrument, it should not be used on works and shall be sent for rectification.
4.2.3 However if standard correction can be applied on the reading taken to obtain the correct levels, consent of QP engineer shall be taken prior to using the instrument.
4.3 SITE SURVEY:
4.3.1 Before the commencement of works, the contractor and QP engineer together shall make a complete survey and take levels of the site and agree all particulars Upon which the setting out works based, including existing plant, buildings, and services.
4.3.2 The contractor shall then do the survey of the area. Drawings shall be prepared detailing all survey information and levels. They shall also show the site grid. After agreement of the drawings they shall be signed by QP engineer and the contractor and shall form the basis of setting out of works.
4.4 CONTOURING AND PLOTTING OF POINTS
4.4.1 When it is a requirement of project documentation or unless or otherwise notified by QP engineer, the contractor shall establish a site grid. The orientation of the site grid shall be determined by the layout of the proposed works and as agreed by the engineer.
4.4.2 The grid spacing shall be 20m in each direction unless otherwise notified by the engineer. The grid notation shall be numerical in one direction i.e. “Y” axis and alphabetic in other direction.
4.4.3 The grids shall be tied to the Qatar Nation Grid. An existing control station related Qatar National Grid would be indicated by QP engineer for the purpose.
4.4.4 A drawing shall be prepared detailing all the survey information and approved by QP engineer. It shall be kept for project documentation.
4.5 SETTING OUT OF WORKS
4.5.1 Setting out of works shall be based Upon agreed site survey by QP engineer and the contractor.
4.5.2 The contractor shall be responsible for
- True and proper setting out of works in relation to the reference data given in the project documentation.
- The accuracy of setting out of positions, the levels and the dimensions of the works.
4.5.3 Setting out for works shall be carried out as per approved drawings and shall be reviewed and approved by QP engineer before commencing the works.
4.6 SITE CLEARING AND GRADING
4.6.1 The site should be cleared off all the waste materials and properly disposed off.
4.6.2 The site is to be prepared, graded and compacted to the levels to the satisfaction of the QP engineer as per the procedure mentioned in Site Work Procedure no. SWP.CS.02-Preparation, General Fill and Compaction.
5.0 RECORDS
5.1 QNHD benchmark reference
5.2 Calibration certificate of Survey instruments
5.3 Survey record/Field Book
5.4 Contour Maps
5.5 Inspection Record
5.6 ITP/Checklist