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HomeMy WebLinkAboutSection 02221 Trench Backfill and Compacting 02221 - 1/3 SECTION 02221 TRENCHING, BACKFILLING AND COMPACTING PART 1 - GENERAL 1.01 SCOPE: A. Summary of Work: The CONTRACTOR shall furnish all labor, materials and equipment necessary for complete and proper trenching, backfilling and compacting as specified herein. 1. SECTION 02200 Earthwork 1.02 APPLICABLE PUBLICATIONS: A. American Society of Testing Materials (ASTM): 1. D698-00a - Standard Test Methods for Laboratory compaction Characteristics of Soil Using the Standard Effort (12,400 ft-lbf/ ft3 (600 kN-m/m3)). 2. D1557-00- Standard Test Methods for Laboratory compaction Characteristics of Soil Using the Modified Effort (56,000 ft-lbf/ ft3 (2,700 kN-m/m3)). 3. D4253-00 - Standard Test Methods for Maximum Index Density and Unit Weight of Soils Using a Vibratory Table. 4. D4254-00 - Standard Test Methods for Minimum Index Density and Unit Weight of Soils and Calculation of Relative Density. B. Florida Department of Transportation (FDOT): 1. Standard Specifications for Road and Bridge Construction, latest edition, (FDOT). C. Miscellaneous Project Data: 1. Subsurface soil data logs are provided for the CONTRACTOR’s reference: 1.03 DEFINITIONS: (Not Used) 1.04 SUBMITTALS: A. Laboratory Reports of testing of materials and densities shall be submitted with applications for payment. 1.05 QUALIFICATIONS: (Not Used) 1.06 RESPONSIBILITIES: A. The CONTRACTOR shall make all excavations for piping and appurtenant structures in any material encountered to the depth and grades required, shall backfill such excavations and dispose of excess or unsuitable materials from excavation, and shall provide and place necessary borrow material to properly backfill excavations, all as indicated on the drawings, specified herein, or as directed by the ENGINEER. B. Excavation, dewatering, sheeting and bracing required shall be carried out so as to prevent any possibility of undermining or disturbing the foundations of any existing structure or work, and so that all work may be accomplished and inspected in the dry, except as directed by the ENGINEER. Aqueous construction may be performed only with prior approval of the ENGINEER. 1.07 CERTIFICATIONS AND TESTINGS: 02221 - 2/3 A. Testing of density of compacted backfill material is required at every 300 LF of trench restoration and for each lift. 1.08 INSPECTION COORDINATION: The CONTRACTOR shall provide access to the WORK for the ENGINEER as requested for inspection. The Contractor shall provide 48 hours notice of its intention to begin new WORK activities. 1.09 WARRANTY: (Not Used) PART 2 - PRODUCTS 2.01 MATERIALS: The CONTRACTOR shall furnish materials as required to complete the Work under this Section. PART 3 - EXECUTION 3.01 EXTENT OF OPEN EXCAVATION: The CONTRACTOR shall perform the excavation such that at any time the amount of excavation open will be held to a minimum consistent with normal and orderly prosecution of the work, or as restricted by permit conditions. 3.02 CUTTING PAVEMENT: When excavations are required in paved areas the CONTRACTOR shall conform to the following. A. When excavations are to be made in paved surfaces, the pavement shall be cut ahead of the excavation by means of suitable sharp tools to provide a uniform sharp edge with minimum disturbance of remaining materials. B. Asphalt paving and other improvements in the right-of-way and on other private property affected by this construction shall be duly protected and, where disturbed, shall be restored or replaced to meet original conditions. 3.03 TRENCH EXCAVATION: The CONTRACTOR shall perform trench excavation in accordance with the following. A. All excavation for piping shall be open cut unless otherwise specified on the plans. Trench sides shall be approximately vertical between an elevation of one foot above the top of the pipe and the centerline of the pipe; otherwise, trench sides shall be as vertical as possible or as required. Trenches may be excavated by machinery to a depth that will not disturb the finish grade. B. Trench width shall be as narrow as practical and shall not be widened by scraping or loosening material from the sides. 3.04 EXCAVATION BELOW NORMAL GRADE: A. In the event the CONTRACTOR through error or carelessness excavates below the elevation required, the CONTRACTOR shall at his own expense backfill with selected gravel and compact to obtain a suitable pipe bedding all as directed and to the satisfaction of the ENGINEER. B. In the event unstable or unsuitable bedding material is encountered at or below the pipe bedding level the CONTRACTOR shall removed such material and replaced with it suitable compacted material. 3.05 BACKFILLING TRENCHES: 02221 - 3/3 A. The CONTRACTOR shall be responsible for obtaining the necessary inspections before, during and after backfilling and shall re-excavate, refill and perform all such related work to obtain satisfactory test results. B. The CONTRACTOR shall use excavated materials classified as embankment fill for backfilling and such grading on the site as is required. The CONTRACTOR shall dispose of any excess of fill or unstable material in areas approved by the ENGINEER. Pipe trenches shall be backfilled with fine, loose embankment fill (see SECTION 02220, paragraph 2.02), free from large stones, carefully deposited on both sides of pipe and thoroughly and carefully rammed until enough fill has been placed to provide a cover of at least one foot above the pipe. The remainder of the backfill material may then be thrown in and tamped. Water settling may be permitted. The CONTRACTOR shall submit written request detailing the need to perform water settling and reasons why work in the dry is not possible. The Contractor shall also submit detailed procedures for the review and approval of the ENGINEER. Whenever trenches have not been properly filled, or if settlement occurs, they shall be refilled, smoothed off and finally, made to conform to the surface of the ground. Backfilling shall be carefully performed and the surface restored to the elevation shown on the plans. In unpaved areas the surface of trenches shall conform and be equal to quality, character and material to the surface immediately prior to making the excavation. C. Place earth embedment as follows: 1. With level bottom layer at proper grade to receive and uniformly support pipe barrel throughout its length. 2. Form shallow depression under each joint to facilitate jointing. 3. Add second layer simultaneously to both sides of the pipe with care to avoid displacement of the pipe. 4. Place material in maximum 12-inch lifts. 3.06 BACKFILLING OF TRENCH UNDER ROADWAY AND AREAS TO BE PAVED: The CONTRACTOR shall place material in 12-inch maximum layers after filling one foot above pipe as previously described. Each layer shall be compacted to 98 percent maximum dry density as measured by ASTM D1557 so that pavement can be placed promptly. Any pavement cut or area disturbed by this work shall be replaced to match existing. 3.07 BACKFILLING OF TRENCH OPEN AREAS: The CONTRACTOR shall place material in 12-inch maximum lifts after filling one foot above pipe as previously described. The top one-foot layer shall be compacted to 95 percent maximum dry density as measured by ASTM D1557. Each layer shall be compacted to the density of adjacent soils. Restore the surface to original grade and place sod or seed as required by the contract documents. END OF SECTION