SECTION 02225

TRENCHING

PART 1 GENERAL

SECTION INCLUDES

Excavate trenches for utilities from [__________] outside building to [municipal utilities.] [_________.]

Compacted bedding under fill over utilities [to subgrade elevations.] [_______________.]

Backfilling and compaction.

RELATED SECTIONS

Section [01400- Quality Control:] [01410 - Testing Laboratory Services]: Testing fill compaction.

Section 01500 - Construction Facilities and Temporary Controls: Water control in excavations.

Section 02202 - Rock removal: Removal of rock during excavation.

Section 02211 - Rough Grading: Topsoil and subsoil removal from site surface.

Section 02218 - Landscape Grading: Filling of topsoil over backfilled trenches to finish grade elevation.

Section 02222 - Excavation: General building excavation.

Section 02223 - Backfilling: General backfilling.

Section 02710 - Subdrainage Systems: Building perimeter tile drainage, [filter aggregate and] filter fabric, and granular cover.

Section [_____-__________:] Sewer piping from building to [municipal sewer.] [__________.]

Section [_____-__________:] [Water] [__________] piping from building to [municipal utilities.] [__________.]

Section [_____-__________:] [Gas] [__________] piping from building to [municipal utilities.] [__________.]

Section 03300 - Cast-in-Place Concrete: Concrete materials.

REFERENCES

ANSI/ASTM C136 - Method for Sieve Analysis of Fine and Coarse Aggregates.

ANSI/ASTM D698 - Test Methods for Moisture-Density Relations of Soils and Soil-Aggregate Mixtures, Using 5.5 lb (2.49 kg) Rammer and and 12 inch (304.8 mm) Drop.

ANSI/ASTM D1556 - Test Method for Density of Soil in Place by the Sand-Cone Method.

ANSI/ASTM D1557 - Test Methods for Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10 lb (4.54 kg) Rammer and 18 inch (457 mm) Drop.

SUBMITTALS

Submit under provisions of Section [01300.] [_____.]

Samples: Submit [10] [_____] lb ([4.5] [_____] kg) sample of [each type of] [Type [_____]] fill to testing laboratory, in air-tight containers.

FIELD MEASUREMENTS

Verify that survey benchmark and intended elevations for the Work are as shown on Drawings.

PART 2 PRODUCTS

FILL MATERIALS

Types [A] [B] [C] [D] [E] [F] [G] [Subsoil] [Concrete] materials as specified in Section [02223.] [_____.]

BED MATERIALS

Type 1 Material: As specified for Type [A] [_____] in Section [02223.] [_____.]

****** [OR] ******

Type 1 - [Coarse Stone] [Crushed] [Gravel] [__________]: [Pit run,] [Angular,] [_____,] [washed] natural stone; free of shale, clay, friable material, sand, debris; graded in accordance with ANSI/ASTM C136 within the following limits:

Sieve_Size	Percent_Passing

2 inches (50 mm)	[100] [_____]

One inch (25 mm)	[95] [_____]

3/4 inch (19 mm) [95] [_____] to [100] [_____] 5/8 inch (16 mm) [75] [_____] to [100] [_____] 3/8 inch (9 mm) [55] [_____] to [85] [_____] No. [4] [_____] [35] [_____] to [60] [_____]

([4.75] [_____] mm)

No. [16] [_____]	[15] [_____] to [35] [_____]

([1.18] [_____] mm)

No. [40] [_____]	[10] [_____] to [25] [_____]

([450] [_____] mm)

No. [200] [_____]	[5] [_____] to [10] [_____]

([75] [_____] micro m)

Type 2 Material: As specified for Type [B] [_____] in Section [02223.] [_____.]

****** [OR] ******

Type 2 - [Pea Gravel] [_____]: Natural stone; [washed,] free of clay, shale, organic matter; graded [in accordance with ANSI/ASTM C136,] to the following:

Minimum Size: [1/4] [_____] inch ([6] [_____] mm)

Maximum Size: [5/8] [_____] inch ([16] [_____] mm)

Type 3 Material: As specified for Type [C] [_____] in Section [02223.] [_____.]

****** [OR] ******

Type 3 - [Sand:] [_____]: Natural river or bank sand; [washed;] free of silt, clay, loam, friable or soluble materials, or organic matter; graded [in accordance with ANSI/ASTM C136,] within the following limits:

Sieve_Size	Percent_Passing

No. [4] [_____]	[100] [_____]

([4.75] [_____] mm)

No. [14] [_____]	[10] [_____] to [100] [_____]

([1.40] [_____] mm)

No. [50] [_____]	[5] [_____] to [90] [_____]

([300] [_____] micro m)

No. [100] [_____]	[4] [_____] to [30] [_____]

([150] [_____] micro m)

No. [200] [_____]	[0] [_____]

([75] [_____] micro m)

Subsoil Material: As specified in Section [02223.] [_____.]

****** [OR] ******

Subsoil: [Reused,] [Imported,] free of gravel larger than [3] [_____] inch ([75] [_____] mm) size, and debris.

Concrete: [Lean concrete] [Structural concrete conforming to Section [03300] [_____] with a compressive strength of [_____] psi ([_____] MPa)].

ACCESSORIES

Geotextile Fabric: [____________________.]

PART 3 EXECUTION

EXAMINATION

Verify fill materials to be reused, is acceptable.

PREPARATION

Identify required lines, levels, contours, and datum.

Maintain and protect existing utilities remaining, which pass through work area.

Protect plant life, lawns, [rock outcropping] and other features remaining as a portion of final landscaping.

Protect bench marks, [existing structures,] [fences,] sidewalks, paving, and curbs from excavation equipment and vehicular traffic.

Protect above and below grade utilities which are to remain.

Cut out soft areas of subgrade not capable of insitu compaction. Backfill with Type [2] [3] [_____] fill and compact to density equal to or greater than requirements for subsequent backfill material.

EXCAVATION

Excavate subsoil required for [storms sewer] [sanitary sewer] [water] [gas] [__________] piping to [municipal utilities.] [__________.]

Cut trenches sufficiently wide to enable installation of utilities and allow inspection.

Excavation shall not interfere with normal [45] [_____] degree bearing splay of foundations.

Hand trim excavation. [Hand trim for bell and spigot pipe joints.] Remove loose matter.

Remove lumped subsoil, boulders, and rock up to [1/3] [_____] cu yd ([0.25] [_____] cu m), measured by volume. Larger material will be removed under Section [02202.] [_____.]

Correct unauthorized excavation at no cost to Owner.

Correct areas over-excavated by error [in accordance with Section 02222.] [_____.]

[Stockpile excavated material in area designated on site [and remove excess material not being used, from site].] [Remove excavated material from site.]

BEDDING

Support pipe [and conduit] during placement and compaction of bedding fill.

BACKFILLING

Backfill trenches to contours and elevations with unfrozen materials.

Systematically backfill to allow maximum time for natural settlement. Do not backfill over porous, wet, frozen or spongy subgrade surfaces.

Place geotextile fabric [over Type [A] [_____] fill] [_______________] prior to placing next lift of fill.

[Granular] [_______________] Fill: Place and compact materials in continuous layers not exceeding [6] [8] [_____] inches ([150] [200] [_____] mm) compacted depth.

[Soil] [_______________] Fill: Place and compact material in continuous layers not exceeding [8] [12] [_____] inches ([200] [300] [_____] mm) compacted depth.

Employ a placement method that does not disturb or damage [foundation perimeter drainage], [conduit] [duct] in trench, [and] [____________________.]

Maintain optimum moisture content of backfill materials to attain required compaction density.

[Remove surplus backfill materials from site.]

Leave fill material stockpile areas completely free of excess fill materials.

TOLERANCES

Top Surface of Backfilling: [Under Paved Areas] [_____]: Plus or minus [one] [_____] inch ([25] [_____] mm) from required elevations.

Top Surface of General Backfilling: Plus or minus [one] inch ([25] [_____] mm) from required elevations.

FIELD QUALITY CONTROL

Field [inspection and] testing will be performed under provisions of Section [01400.] [_____.]

Tests and analysis of fill material will be performed in accordance with ANSI/ASTM [D698] [D1557] and with Section [01400.] [01410.]

Compaction testing will be performed in accordance with [ANSI/ASTM D1556] [ANSI/ASTM D1557] [ANSI/ASTM D698] and with Section [01400.] [01410.] [_____.]

If tests indicate Work does not meet specified requirements, remove Work, replace and retest at no cost to Owner.

Frequency of Tests: [______________.]

PROTECTION OF FINISHED WORK

Protect finished Work under provisions of Section [01500.] [_____.]

Recompact fills subjected to vehicular traffic.

SCHEDULE

Storm and Sanitary Piping:

Bedding Fill: Type [1] [_____], [_____] inches ([_____] mm) thick, compacted to [95] [_____] percent,

[Cover with [Common] [Type [1] [_____]] fill, in [8] [_____] inch ([200] [_____] mm) lifts, compacted to [95] [_____] percent.]

Power Ducts:

Bedding fill of Type [3] [_____], [_____] inches ([_____] mm) thick, compacted to [_____] percent,

Remaining fill of [Subsoil] [Type [_____]], [to subgrade elevation] [__________], compacted to [_____] percent.

END OF SECTION