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METHOD STATEMENT FOR EARTHWORKS-GRANULAR SUBBASE MATERIALS

VIEWS: 1,492 PAGES: 9

									SITE WORK METHOD STATEMENT                        Doc. No.
Department QA/QC                                  Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS   Date




       SITE WORK METHOD STATEMENT

     LAYING OF GRANULAR SUBBASE MATERIALS




                            REVISION HISTORY

 2     Revision-2

 1     Revision-1

 0     Original Issue

Rev.                    Revision information                  Date

       Originated by

        R. R. Aniñon




                                                             Page 1 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                      Doc. No.
Department QA/QC                                                Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS                 Date


                   LAYING OF GRANULAR SUBBASE MATERIALS


1.0 OBJECTIVE


            The purpose of this method of statement is to define the procedures to
            ensure that the proposed materials and workmanship to be used at the
            above site are complying with the condition / requirements as stipulate
            in the Qatar Construction specifications.



2.0 SCOPE

            The scope of work shall consist of establishment of level pegs, setting up
            and laying of Granular Sub base Materials using approved equipment as
            being applied during trial compaction.


3.0 REFERENCE


             Grading Sheets

             Profile

             Construction drawing

4.0 EQUIPMENT

               Dump Truck
               Shovel
               Service Vehicle for General Workers
               Roller
               Grader
               Paving Machine




5.0 MANPOWER

                                                                               Page 2 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                      Doc. No.
Department QA/QC                                                Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS                 Date


             Supervising Engineer
             Foreman
             Operator
             Driver
             Skilled Workers
             Surveyor
             Survey Aide
             Safety Officer
             Unskilled Workers


6.0 SAFETY, HEALTH & ENVIRONMENTAL ISSUES

           Conditions and precautions listed in the project specifications
            shall be followed as minimum.


           All staff involved with the project shall be inducted on the safety,
            health and environmental issues associated with the work.

           Only trained personnel with relevant experience shall be allowed
            to handle machinery.

           Appropriate Safety Signboards, barriers and lighting shall be
            and other safeguards shall be provided as required by the nature
            of and location of the works. All operations shall be carried out in
            accordance with the safety requirements.


           All field personnel will use PPE safety requirements like safety shoes
            helmets, cover all, goggles and dust mask, etc as required.




                                                                               Page 3 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                  Doc. No.
Department QA/QC                                            Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS             Date


7.0 PROCEDURE:

7.1 SPREADING & COMPACTION:


           Before commencing the construction of the sub-base and road base,
            written approval from the Engineer must be obtained that the sub
            grade is in compliance.

           The optimum moisture content of the material shall be noted from the
            mix design and the actual moisture content determined at the plant
            after mixing.

           If the natural moisture content is less than the optimum moisture
            content, the necessary amount of water must be added to obtain the
            optimum content.

           Allowance shall be made for the quantity of moisture which may be lost
            by evaporation in the process of raking, leveling and compacting,
            depending on atmospheric temperature.

           The compacted layer shall have a moisture within + or – 2 % of the
            optimum moisture content.

           The moisture content shall be uniform in all parts of the section where
            the work is being carried out and in the various depths of the layer
            thickness.

           Road base shall be laid by a paving machine with a spreader box.
            Sub-bas may be laid by either a paving machine with a spreader box
            or end tipped from trucks and spread by grader.

           Compaction shall start immediately the material has been laid as per
            the approved rolling pattern.

           Work on the sub-base and road base shall not be permitted during
            rainy weather.




           Material shall be spread to a thickness that would result in layers not
            more than 200 mm thick after compaction. Where the finished
            compacted thickness exceeds 200 mm placing shall be executed in
                                                                           Page 4 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                   Doc. No.
Department QA/QC                                             Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS              Date

              composite layers each layer not exceeding 200 mm in compacted
              thickness as directed by the Engineers.

           The course shall not be rolled when the underlying material is soft or
            yielding or when the rolling causes a wave-like motion in this course.

           When the rolling develops irregularities, the irregular surface shall be
            loosened, then refilled with the same kind of material as used in
            constructing the course and again rolled.

           Along places inaccessible to rollers, the sub-base or road base course
            material shall be tamped thoroughly with suitable mechanical tampers
            to achieve the required density and finish.

           Rolling must continue until a relative density of not less than 100 % of
            the maximum dry density has been obtained as determined by the
            moisture-density relationship in CML 12-97.

           Care shall be taken so that layers already compacted under the layer
            being executed is not damaged, or that the formation is not damaged.

           This aspect must be given special attention in places where rolling
            equipment makes turns to change direction.

           Any such damage resulting in mixing the various layers constituting the
            different sub grades and road base courses shall be carefully made
            good by the Contractor at his own expense and to the satisfaction of
            the Engineer.




                                                                            Page 5 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                    Doc. No.
Department QA/QC                                              Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS               Date

7.2 CORRECTIVE ACTION


           Any material that fails to meet test requirements shall either be
            reworked then retested to check for compliance.

           Any soft spots, irregularities or depressions that develop in the surface
            of the sub-base or road base, shall either be corrected by loosening
            the surface of such areas and adding further material, or by removing
            the material in such areas and replacing with further approved
            material.

           In the event of heave occurring during compaction, caused either by
            excessive build-up of pore water pressure or the groundwater table
            being sufficiently high to affect construction techniques, either of the
            following procedures shall be adopted subject to the approval of the
            Engineer:

              (a) sufficient time shall be allowed to elapse enabling the excess pore
              water to dissipate before further construction or compaction is carried
              out.

              (b) the affected material shall be removed, and approved alternative
              construction layers substituted.

           For correction of low density, the top 75 mm shall be scarified,
            reshaped with material added or removed as necessary and
            recompacted to the designated requirement. The area treated shall not
            be less than 30 meters long and 2 meters wide or such area
            determined by the Engineer as necessary to attain compliance.

           Where the surface of the sub-base is covered in a very thin smooth
            skin composed of fine particles an air blower shall be used or the
            surface should be watered if necessary, and recompacted prior to the
            application of prime coat.

           The Contractor shall carry out additional testing if required by the
            Engineer to ensure that the standard of compaction is satisfactory
            through the full depth of the layer.




                                                                             Page 6 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                    Doc. No.
Department QA/QC                                              Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS               Date

7.3 PROTECTION OF SURFACE:


           The Contractor shall protect the sub-base or road base course so that
            it shall be maintained sound during work progress, after its completion
            and before receiving the bituminous layers or before laying the surface
            overlay thereon.

           Any damage cause to the layer if exposed to traffic or natural
            conditions resulting in damage to its surface shall be made good at the
            expense of the Contractor and to the satisfaction of the Engineer.

           The Engineer has the right to stop all hauling over completed or
            partially completed sub-base and road base courses when in his
            opinion such hauling is causing damage.

           Following the completion of the sub-base or road base courses the
            Contractor shall perform all maintenance work necessary to keep the
            course in a condition for priming.



7.4 TESTING


           All testing shall be carried out in accordance with AASHTO T96,
            AASHTO T104 and the relevant Parts of BS 1377 or CML Standard
            Methods of test.

           Prior to proceeding with the mixing of material individual stockpile shall
            be tested for compliance to the requirements of QCS clause 4.2.

           At any stage in the mixing, transportation, spreading or compaction
            process,, the Engineer may instruct that these tests are carried out.

           Before the application of any prime coat or any other paving course,
            the aggregate sub-base and road base shall have been tested for
            compliance with the requirements of this clause on testing and
            approved by the Engineer.




                                                                              Page 7 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                   Doc. No.
Department QA/QC                                             Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS              Date


7.5 COMPACTION


           The sub-base or road base shall be compacted and tested for
            acceptance in accordance with CML 12-97 and BS 1377 to attain a
            minimum density of 100% of the maximum dry density of the material.
            Two tests for every 500 sq.m. shall be carried out unless directed by
            the Engineer.

           Wherever the degree of compaction is found to be less than required,
            the area of sub-base or road base involved shall be satisfactorily
            corrected.



7.6 EVENNESS AND LEVEL



           The finished surface shall also be checked by dips or spot levels and
            shall be constructed to the designated grade levels to within + or – 10
            mm.

           Where these requirements are not met, the Contractor shall determine
            the full extent of the area which is out of tolerance and shall make
            good the surface of the course by scarifying, adding or removing
            material as necessary, adding water if necessary and recompacting.




ADDENDUM:

           Materials will be submitted to an approved independent laboratory for
            testing according to QCS 2007.

           Sub base layer shall not exceed 150mm thick (ie to be placed in 2
            layers if the thickness of the sub base is more than 150mm.

           Soft spot for laid area will be removed and replaced with good material.
                                                                            Page 8 of 9
Owner: BOTC
SITE WORK METHOD STATEMENT                                  Doc. No.
Department QA/QC                                            Rev.
Title      LAYING OF GRANULAR SUBBASE MATERIALS             Date


           For evenness, checking of road base level shall be by dipping method.

           For transversal and longitudinal checking, 3 m long straight edge will
            be used.




                                                                          Page 9 of 9
Owner: BOTC

								
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