02200_Earthwork _ ADDENDUM 2.pdf

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SECTION 02200 – ADDENDUM 2

EARTHWORK

1. WORK INCLUDED: Earthwork for this project includes, but is not necessarily limited to:

A. Excavation for structures;

B. Furnishing and installing graded aggregate base under all concrete slabs on grade;

C. Filling and backfilling to attain indicated grades;

D. Trenching and trench backfilling;

E. Rough and finish grading around structures;

2. RELATED WORK

A. Testing Section 01410

B. Grassing and Mulching Section 02486

3. SITE CONDITIONS

The accuracy of information contained in the plans and specifications as to topography, underground structures, foundation conditions, character of soil, position and quantity of ground and subsoil water, are not guaranteed by the Owner. Bidders must satisfy themselves by personal examination and by such other means as they desire with respect to actual site conditions.

Unforseen conditions shall not constitute a claim for increased compensation under the terms of the contract, nor constitute a basis for the cancellation thereof.

4. JOB CONDITIONS

A. Erect sheeting, shoring and bracing as necessary for protection of persons, structures and excavations.

B. Provide dewatering and drainage as required to accomplish work.

5. QUALITY ASSURANCE

A. Testing Agency

1. In place soil compaction tests to be performed by a testing laboratory employed by the Contractor.

2. If the compaction does not meet the Specification, the Contractor shall remove the part of embankment not meeting the specifications and replace with properly compacted material and shall pay for all compaction tests made for such defective areas.

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B. Reference Standards

1. ASTM D698-78, Moisture-Density Relations of Soils

2. ASTM D1556-64, Density of Soil in Place by the Sand-Cone Method.

6. FILL MATERIAL, GENERAL

A. Fill material shall consist of soil or soil-rock mixture which is free from topsoil, organic matter, and other deleterious substances. Large boulders, thick rock or quartz layers which are not broken down by compaction equipment will not be suitable for use in the fill.

B. Fill material shall be subject to the approval of the Engineer.

7. TRENCH AND STRUCTURAL BACKFILL

A. On-site fill material used for trench and structural backfill shall meet the requirements of Article 6 above. Material shall be free of rock or stone larger than two inches.

B. Granular material when required for trench and structural backfill shall be free from organic substance and other deleterious matter, shall be subject to the approval of the Engineer, and shall be in particle size grading within the following limits:

(1) Passing the number four sieve: 100%

(2) Passing the number 200 sieve: 3% Maximum

8. AGGREGATE BASE UNDER CONCRETE SLAB

Aggregate base under concrete slabs on grade, where shown on the plans, shall be clean mineral aggregate with particle size grading within the following limits:

(1) Passing the one inch mesh: 100%

(2) Passing the number four sieve: Not more than 5%

(3) Passing the number 200 sieve: Not more than 1%

9. RIP RAP

The stone used for rip-rap shall meet the requirements of Section 805 of Ga. D.O.T.

Specifications, "Stone for Plain Rip-Rap".

10. NON-SPECIFIED MATERIALS

All other materials, not specifically described but required for a complete and proper installation, shall be as selected by the Contractor subject to the approval of the Engineer.

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11. GENERAL

A. Prior to all work of this Section, become thoroughly familiar with the site, the site conditions, and all portions of the work falling within this Section.

B. Do not allow or cause any of the work performed or installed to be covered up or enclosed by work of this Section prior to all required inspections, tests, and approvals.

Should any of the work be so enclosed or covered up before it has been approved, uncover all such work at no additional cost to the Owner.

C. The Contractor will provide erosion and sediment control as shown on the plans. All erosion control measures taken shall comply with the Manual for Erosion and Sediment Control in Georgia (“the Manual”). The contractor shall periodically inspect and maintain all erosion control devices. Note that ANY statement or requirement of these specifications that conflicts or differs with the latest edition of the Manual for Erosion and Sediment Control in Georgia, the requirements of the Manual shall take precedence and govern the erosion control measures. Also, the requirements of the EPD’s GAR 100002 NPDES permit shall govern and control erosion control efforts of the Contractor.

12. EXCAVATION

A. Excavate to grades shown on the Drawings. Where excavation grades are not shown on the Drawings, excavate as required to accommodate the installation. Extend excavation as required for proper formwork construction.

B. Backfill and compact all overexcavated areas as specified for fill below, and at no additional cost to the Owner unless so directed by the Engineer in which case the contractor shall be paid the price bid per cubic yard.

C. Control grading in vicinity of structures to prevent surface water from running into excavated areas.

D. Where depressions result from, or have resulted from the removal of surface or subsurface obstructions, open the depression to equipment working width and remove all debris and soft material as directed by the Engineer.

E. Solid rock excavation.

1. Notify the Engineer when rock is encountered and before its removal.

2. Rock excavation shall be defined as solid rock in the original bed, or well defined ledges, or boulders and detached pieces or rock containing more than 1/2 cubic yard of rock each, which require drilling, blasting or the use of jack hammers to remove.

3. Blasting operations shall be conducted in strict accordance with all existing ordinances and regulations, and shall be done by personnel licensed to use explosives. All structures shall be carefully protected and the blast covered by suitable material.

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4. Any damage caused by blasting shall be promptly repaired by the Contractor at his own expense. Explosives and other blasting supplies shall be stored in accordance with all state and local laws. Where rock is encountered in pipe trenches, foundation footings, pump pits and other parts of structures, the rock shall be removed to at least 6 inches below the bottom of the pipe, footings, pump pits, and other parts of structures. Then the surface shall be brought back to grade of the bottom of the structure by backfilling in 6" layers with selected material and tamping to the same average density of the undisturbed earth adjacent thereto.

13. TRENCHING

A. Trench excavation shall be by open cut from the ground surface, unless otherwise called for on the plans or allowed by the Engineer. Not more than 100 feet of trench shall be opened on any line in advance of pipe laying.

B. Pipe trenches shall be straight and true to grade and in the location shown on the plans.

The bottom of the trenches shall be hand dressed so that the pipe has an even bearing on solid undisturbed earth throughout its entire length between bell, or coupling holes.

C. Bell holes shall be excavated at all pipe joints for bell and spigot and mechanical joint pipe. Bell holes shall be large enough to facilitate the proper installation of all joints. No part of the pipe bell or coupling shall be in contact with sides or bottom of the trench.

D. All trenches shall be of sufficient width to provide ample working space on each side of the pipe for maintaining a straight line of pipe.

E. Sewer lines shall be laid at the elevations indicated.

14. FILL UNDER STRUCTURES

A. Prior to placing any fill material, the subgrade shall be proof-rolled in the presence of the Engineer. Any unstable areas shall be repaired and the placing of fill materials shall proceed only after inspection and approval by the Engineer.

B. Approval of the fill material by the Engineer shall be required prior to initiating filling operations.

C. No fill shall be placed or compacted in a frozen condition or on top of frozen material.

No fill material shall be placed when free water is standing on the surface of the area where the fill is to be placed and no compaction of fill will be permitted with free water on any point of the surface of the fill to be compacted.

D. Scarify existing surfaces to provide bond with new material.

E. Place fill and backfill in layers not exceeding six inches before compaction and thoroughly tamp with a sheepsfoot roller unless other wise indicated or specified.

Compact to a density of not less than 95% of the maximum laboratory dry density, as determined by ASTM D698. The final two 6" lifts that brings the backfill to sub-grade shall be compacted to 98% of the maximum laboratory dry density, as determinated by ASTM 0698. If necessary, in order to obtain the required compaction, the Contractor

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F. Stones in earth fill must be well distributed and no stones over four inches in diameter may be left within 36 inches of finished grade.

15. BACKFILLING AROUND STRUCTURES

A. Backfilling around structures shall not proceed until authorized by the Engineer.

B. All formwork, debris and other undesirable material shall be removed prior to backfilling.

Area shall be dewatered.

C. Backfill material shall be as specified in this section. Backfill shall be placed in layers of

6 inches maximum and shall be of a moisture content which will permit proper compaction. Each layer shall be compacted by mechanical tampers and special care shall be taken to prevent uneven loading or damage to the structure.

D. Compact backfill material to a minimum relative density of 95% as determined by ASTM

D698 (Standard Proctor).

16. BACKFILLING TRENCHES

A. The backfilling of pipe trenches shall be started immediately after the pipe installation has been approved by the engineer.

B. Backfill material shall be as specified in this section. The material shall contain no rock greater than two inches in maximum dimension.

C. Backfill shall be tamped in layers not over 6 inches thick. Tamping shall be done with mechanical tamps in such a manner as to thoroughly compact the backfill without moving or injuring the pipe. The remainder of the backfill may be placed in the trench by a machine, but the backfill shall be compacted to the top of the trench, either by pneumatic hand tamps, hydro-tamps, or other approved methods. After compaction, the dry weight per cubic foot shall be at least 95 percent of the maximum laboratory dry weight per cubic foot as determined by ASTM D698. The trench shall be backfilled and the surface brought to its original grade and profile contour.

D. In rock excavation, the backfill from the bottom of the trench to one foot above the top of the pipe shall be finely pulverized soil, free from rocks and stones. The rest of the backfill shall not contain over 75% broken stone, and the maximum sized stone placed in the trench shall not have a weight exceeding 50 pounds. Excess rock and fragments of rock weighing more than 50 pounds shall be loaded and hauled to disposal as directed by the Engineer.

17. FINISH GRADING

A. The contractor shall employ a competent person to interpret elevations and grading details shown on plans.

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B. Areas to be grassed shall be spread with selected topsoil that has been obtained from site clearing. The topsoil shall be mixed into the surface and compacted suitably for planting.

C. Areas around buildings and structures shall be graded so as to prevent accumulation of water within the area.

18. TEMPORARY EROSION CONTROL

A. The Contractor will provide erosion and sediment control as shown on the plans. All erosion control measures taken shall comply with the Manual for Erosion and Sediment Control in Georgia (“the Manual”). The contractor shall periodically inspect and maintain all erosion control devices. Note that ANY statement or requirement of these specifications that conflicts or differs with the latest edition of the Manual for Erosion and Sediment Control in Georgia, the requirements of the Manual shall take precedence and govern the erosion control measures. Also, the requirements of the EPD’s GAR 100002 NPDES permit shall govern and control erosion control efforts of the Contractor.

19. DISPOSAL OF EXCESS MATERIAL

A. Excess material may be disposed of on site in areas selected by the Contractor and approved by the Engineer.

B. Disposal sites shall be cleared and grubbed and topsoil stockpiled as required in Section

02100.

C. Disposal sites shall be graded to be free draining, with side slopes no greater than 3:1, and to fit the existing topography.

D. Upon completion of work at the disposal sites, the areas shall be finish graded as required in this section and grassed and mulching as required in section 02600.

20. GROUND WATER

Control of ground water shall be accomplished in a manner that will preserve the strength of the foundation soils, will not cause instability of the excavation slopes, and will not result in damage to existing structures. Where necessary to these purposes, the water level shall be lowered in advance of excavation, utilizing wells, well points or similar methods. The water level, as measured in piezometers, shall be maintained a minimum of three feet below the prevailing excavation level. Open pumping with sumps and ditches, if it results in boils, loss of fines, softening of the ground or instability of slopes, will not be permitted. Wells and well points shall be installed with suitable screens and filters so that continuous pumping of fines does not occur.

The discharge shall be arranged to facilitate collection of samples by the Engineer. Silt collection bags shall be installed and utilized to prevent the loss of silt into state waters.

**END OF SECTION**

EARTHWORK