25-Sec 31 23 33 - Excavation, Backfill and Compaction.pdf

EXCAVATION, BACKFILL AND COMPACTION

31 23 33-1

SECTION 31 23 33

PART 1 - GENERAL

1.01 SECTION DESCRIPTION

A. The Work of this Section Includes:

1. Excavation, backfill and compaction associated with foundation removal.

1.02 RELATED SECTIONS

A. Related Work Specified Elsewhere:

1. Section 01 56 39: Landscape Protection

2. Section 01 57 13: Soil Erosion and Sediment Control

3. Section 03 30 00: Concrete Work for Structures

4. Section 03 30 53: Concrete Work for Utilities

5. Section 22 11 34: Water Service Facility

6. Section 31 11 00: Clearing and Grubbing

7. Section 31 23 16.26: Rock Removal

8. Section 32 12 23: Restoration of Paved Surfaces

9. Section 32 93 00: Landscaping

10. Section 33 05 23.16: Boring or Jacking Operations

11. Section 33 05 29: Stream Crossing

12. Section 33 11 00: Water Mains

13. Section 33 12 13: Water Service Connections

14. Section 33 31 13: Gravity Sanitary Sewer Pipe

15. Section 33 32 18: Sewage Pumping Station

16. Section 33 34 00: Sanitary Force Main and Appurtenances

17. Section 33 39 13: Sanitary Manholes

1.03 QUALITY ASSURANCE

A. Testing Agent:

1. Compaction testing for this Work shall be performed by Contractor at the discretion of the Resident Project Representative except if required by the PennDOT Highway

Occupancy Permit or Township Road Opening Permit. Where compaction testing is required by permit, such compaction testing shall be performed by an independent soils testing agent engaged and paid for by Contractor and approved by Engineer.

2. Contractor shall pay the cost of one series of tests on the area being evaluated.

Contractor shall also pay the cost for additional testing as required in the event of improper performance of the Work.

B. Reference Standards:

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1. Pennsylvania Department of Transportation:

Regulations Governing Occupancy of Highways by Utilities (67 PA Code, Chapter 459)

Publication 408 Specifications

Pennsylvania Test Method, PTM 106

Pennsylvania Test Method, PTM 402

Publication 203, Work Zone Traffic Control

2. American Society for Testing and Materials (ASTM):

ASTM D1557 Test Method for Laboratory Compaction Characteristics of Soil

Using Modified Effort (56,000 ft.- lbf/ft3)

ASTM D2922 Standard Test Method for Density of Soil and Soil - Aggregate in nPlace by Nuclear Methods (Shallow Depth)

C. Compaction Testing:

1. Conduct compaction tests at locations on 50 foot centers (1 per 2500 square feet) or closer as required for every 12 inches of fill placed.

1.04 SUBMITTALS

A. Certificates:

1. Submit certified compaction testing results from the soils testing agency for any required compaction testing in accordance with Section 01 33 00.

1.05 JOB CONDITIONS

A. Classification of Excavation:

1. All excavation work performed under this contract is UNCLASSIFIED.

B. Compaction of Backfill:

1. Excavations shall be backfilled in lifts not exceeding compacted thicknesses noted in

Paragraph 3.11C. Each lift shall be individually compacted.

2. The following percentages of maximum dry density shall be achieved:

Modified

Effort

ASTM D1557

• Building Foundation and 95%

Structural Slab-on-Grade

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• Exterior Side of Structure Walls 95% to point 5' from building wall, then 90%

• Trench Backfill under Pavement 95%

(not including base course materials)

• Trench Backfill within Unpaved Areas 90%

3. Contractor shall maintain moisture content of backfill materials at or near the optimum moisture content to attain the required compaction density.

D. Control of Traffic: (N/A)

E. Protection of Existing Utilities and Structures: (N/A)

F. Protection of Trees and Shrubs:

1. See Section 01 56 39

2. Any trees and/or shrubs to be protected which are damaged or destroyed during construction may be required to be replaced in kind as required by Owner.

PART 2 - PRODUCTS

PART 3 - EXECUTION

3.01 EXAMINATION & PREPARATION

A. Identify required lines, levels, contours and datum.

B. Notify Engineer of unexpected subsurface conditions and discontinue work in area until notified to resume work.

C. Maintain and protect existing utilities identified by utility users within the Work area (see paragraph 1.05E).

D. Verify that structure walls are braced to support surcharge forces imposed by backfilling operations.

3.02 PROTECTION OF ADJACENT WORK

A. Underpin adjacent structures which may be damaged by excavation work, including utilities and pipe chases.

B. Grade excavation top perimeter to prevent surface water runoff into excavation or to adjacent properties.

3.03 MAINTENANCE AND PROTECTION OF TRAFFIC

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A. Coordinate the work to insure the least inconvenience to traffic.

B. Maintain access to all streets and private drives.

C. Provide and maintain signs, flashing warning lights, barricades, markers, and other protective devices as required to conform with construction operations and to keep traffic flowing with minimum restrictions.

D. Comply with State and local Municipal codes, permits and regulations.

E. See Section 01 55 26 on Traffic Regulation.

3.04 CUTTING PAVED SURFACES

3.05 EXCAVATION

3.06 SUPPORT OF EXCAVATION

3.07 CONTROL OF EXCAVATED MATERIAL

A. Keep the ground surface, within a minimum of 2' of the sides of the excavation, free of excavated material.

B. Provide temporary barricades to prevent excavated material from encroaching on private property, walks, gutters, and storm drains.

C. Maintain accessibility to all fire hydrants, valve pit covers, valve boxes, curb boxes, fire and police call boxes, and other utility controls at all times. Keep gutters clear or provide other satisfactory facilities for street drainage. Do not obstruct natural water courses. Where necessary, provide temporary channels to allow the flow of water either along or across the site of the work.

D. In areas where excavations parallel or cross streams, ensure that no material slides, is washed, or dumped into the stream course. Remove diversion structures and/or cofferdams immediately upon completion of construction within the stream (See Section 33 05 29).

3.08 DEWATERING

A. Keep excavations dry and free of water. Dispose of precipitation and subsurface water clear of the work.

B. Maintain pipe trenches dry until pipe has been jointed, inspected, and backfilled, and concrete work has been completed. Prevent trench water from entering pipelines under construction.

C. Intercept and divert surface drainage away from excavations. Design surface drainage systems so that they do not cause erosion on or off the site, or cause unwanted flow of water.

D. Comply with Federal and State requirements for dewatering to any watercourse, prevention of stream degradation, and erosion and sediment control. (See Section 01 57 13).

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3.09 BACKFILLING EXCAVATIONS

A. Unsuitable Backfill Material and/or Compaction:

1. Where the Resident Project Representative deems backfill material to be unsuitable and rejects all or part thereof due to conditions prevailing at the time of construction, remove the unsuitable material and replace with suitable backfill material.

2. If, during progress of the Work, tests indicate that compacted materials do not meet specified requirements, remove defective material, replace and retest at no cost to

Owner, as directed by the Resident Project Representative.

3.10 DISPOSAL OF EXCAVATED MATERIAL

3.11 ROUGH AND FINE GRADING

A. Grade areas disturbed by construction to a uniform finish. Form the bases for terraces, banks, lawns and paved areas.

B. Grade areas to be topsoiled and seeded to 4" below indicated finish contours.

3.12 RESTORATION OF UNPAVED SURFACES

A. Restore unpaved surfaces disturbed by construction to equal the surface condition prior to construction.

B. Restore grassed areas in accordance with Section 32 93 00, Landscaping.

3.15 RESTORATION OF PAVED SURFACES

END OF SECTION