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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
"METHOD STATEMENT FOR EARTHWORKS-GRANULAR SUBBASE MATERIALS"