2-Technical Specifications.pdf

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1. TP 3.0 EXCAVATION, TRENCHING AND BACKFILLING…

2. TP 11.0 INDIVIDUAL SEPTIC TANK

3. TP 19.0 INDIVIDUAL GRAVITY CHAMBER DRAINFIELDS

(CONVENTIONAL, STEP-DOWN AND SAND-LINED)

TABLE OF CONTENTS

1/06 Technical Provisions TP 3.0 Excavation, trenching and Backfilling

TECHNICAL PROVISION 3.0

EXCAVATION, TRENCHING AND BACKFILLING

3.01 Scope of Work

The work covered by this section includes the furnishing of all plant, labor, tools, equipment, and material, and performing all operations in connection with the excavation, trenching, and backfilling for the installation of all pipelines, structures, and accessories, all in accordance with these technical provisions and applicable drawings.

3.02 Protection of Excavation

In conformance with applicable safety regulations, the Contractor shall provide suitable shoring and sheeting to protect all excavations and provide safe working conditions for workers.

3.03 Excavation

3.03.01 General

All excavation required for the performance of this contract shall be made by open cut methods unless otherwise shown on the drawings, required by applicable encroachment permits, or approved in writing by the Project Manager.

3.03.02 Trench Excavation

The sides of all trenches for the installation of utility piping systems shall be as nearly vertical as soil conditions permit below the level of the top of the pipe. The width of the trench shall not be less than 12-inches or more than 24-inches wider than the outside diameter of the pipe barrel. Trench excavation shall be centered on pipe alignment such that a minimum clear space of 6-inches is provided on each side of the pipe. Trench width above the level of the top of the pipe may be as wide as necessary for shoring and sheeting, and for proper installation of the work.

The depth of all trenches shall be as indicated on the drawings. If not otherwise specified, the depth of all trenches shall be sufficient to provide a minimum cover of 24- inches at all locations after final backfilling.

Unless otherwise required by applicable permits to be less, the maximum length of trench that may be left open at any one time shall not exceed 500-feet. No trenches shall be left open unless otherwise permitted in writing by the Project Manager.

All trench excavation shall comply with Federal and local OSHA regulations for trench safety.

3.03.03 Pavement Cutting

Where it is necessary to remove sections of asphalt pavement, the asphalt shall be saw-cut with approved equipment in a neat line 6-inches back from the outside edge of the excavation in order to provide a key when restored, or as approved by BIA roads permit or Tribal Manager.

Where it is necessary to remove sections of concrete pavement, the concrete shall be saw-cut to a depth of not less than 2-inches with neat, vertical, true lines in such a manner that the adjoining surface will not be damaged.

3.04 Placement and Compaction of Pipe Embedment and Backfill Material

3.04.01 Pipe Embedment

Pipe embedment is defined as that material required to bring the trench bottom up to grade and that material placed alongside and above pipe to a level of at least 6 inches over the top of the pipe. The pipe embedment area is divided into three zones as defined below.

Bedding: Bedding is that portion of pipe embedment zone beneath the pipe. If the native soil is suitable for bedding the pipe without over- excavation, the bottom of the trench shall be accurately shaped such that one fourth of the pipe circumference is provided with uniform bearing and support for each section of the entire length of the pipe. Imported bedding material shall likewise be placed to provide uniform and adequate longitudinal support under the pipe. Bedding material shall be placed and compacted in lifts not to exceed 6-inches in loose measure.

Haunching: Haunching is that portion of the pipe embedment zone from the bottom of the pipe to the springline of pipe. Haunching material shall be placed and consolidated to provide adequate side support to the pipe while avoiding both vertical and lateral displacement of the pipe from proper alignment.

Initial Backfill: Initial backfill is that portion of the pipe embedment zone from the springline of the pipe to a minimum level of 6-inches over the top of the pipe. Initial backfill material shall be placed and compacted in lifts not to exceed 6 inches in loose measure. Compaction shall be performed in a manner to avoid damage and disturbance of the embedded pipe.

3.04.02 Compaction

Unless otherwise specified by applicable permits or roadway authority, bedding, haunching, initial backfill, final backfill, and gravel resurfacing shall be compacted to the following percent of the maximum density as determined by ASTM D1557. In-place densities of materials shall be determined by the sand-cone method, ASTM D1556 or by nuclear methods, ASTM D2922.

Percent of Maximum Density

Location Bedding Haunching Initial Backfill

Final Backfill

Roadways and Driveways 95% 95% 95% 95%

Unimproved Surfaces, Fields, Etc. 90% 90% 70% 70%

3.05 Surface Restoration and Resurfacing

3.05.01 General

The inclusion of a bid item and estimated quantity for asphaltic, concrete, or gravel resurfacing in the Bid Schedule indicates that these items are probable. However, the exclusion of these items from the Bid Schedule does not preclude the possibility that they will be required, merely that they are not anticipated. If unanticipated resurfacing is required, unit prices will be negotiated between the Contractor and the Contracting Officer.

3.05.02 Surface Restoration

After the piping and structures have been installed and all backfilling has been completed, areas which were disturbed shall be brought to true grades. All slopes shall be trimmed and dressed, and all surfaces graded to maintain existing drainage. All streets, alleys, driveways, sidewalks, curbs, or other surfaces which have been disturbed or damaged shall be resurfaced with like materials to a condition equal to or better than the original condition. All excess excavated material shall be properly disposed of by the Contractor.

3.05.03 Asphaltic Resurfacing

At all locations where asphaltic resurfacing is required, a compacted gravel base, 6-inches in depth shall be placed prior to placement of the asphaltic wear course. This base course shall be 95 to 100 percent 3-inch minus gravel with not more than 40 percent passing a 0.0165 inch square opening (No. 40 sieve). Asphalt shall be plant mixed, with certification that the mix meets the requirements of the applicable roadway authority. Except where greater thickness is required by applicable roadway authority, the minimum thickness of the asphalt shall be the greater of 2-inches or that of the existing adjacent asphalt. Placement of asphalt shall be in lifts not exceeding 2-inches.

Compaction shall be accomplished by pneumatic-tired or steel rollers throughout the spreading operation. Final rolling shall be by steel roller. No surfacing shall be placed while the subgrade is wet, if it is raining, or if the temperature is below 40 degrees F. All edges shall be clean and tack coated prior to placement of the patch.

3.05.04 Gravel Resurfacing

All gravel resurfacing shall be done on a properly compacted subgrade. The gravel shall be spread uniformly and compacted to a minimum thickness of 3-inches. The gravel shall conform to the following gradation requirement.

3.06 Open Cut Road Crossing for Water and Sewer Service Lines

Open cut water and sewer service line crossings shall be completed at all locations shown on the site plan. The Contractor is responsible to comply with all local, county, Tribal and BIA road

Sieve Size Percent Passing Square Opening By Weight

3/4 inch 100

0.250 inch (No. 3 sieve) 50-65

0.0029 inch (No. 200 sieve) 5 max.

crossing provisions whether a permit was issued or not. PVC encasement pipe shall be the diameter shown on the drawings and shall conform to material specification ASTM D1784, Type 1, Grade 1, manufacturing specification ASTM D2241, and the pipe shall be PVC schedule 80. All PVC pipe joints shall be rubber compression ring type with rubber gaskets conforming ASTM F477, and equal to J-M Ring Tite PVC Pressure Rated Pipe, or PWPipe TwinSeal PVC.

Steel encasement pipe and fittings shall be the diameter shown on the drawings and shall be Schedule 40 and shall conform to ASTM A120. The pipe shall be joined by the use of threaded steel couplings

3.07 Bored Type Road Crossing for Water and Sewer Service Lines

Water service lines crossing roads or rights-of-way (ROWs) which cannot be open cut, and if noted on the site plan, the crossing shall be bored. The Contractor shall bore the crossing by using a pneumatic or hydraulic boring machine such as a Hole Hog®, or other approved boring equipment.

Minimum allowable encasement pipe diameter for the crossing shall be of sufficient size to allow the water or sewer service line to be easily slid into position. Casing pipe diameter and material shall be approved by the Project Manager prior to installation

1/06 Technical Provisions TP 11.0 Individual Septic Tank

TECHNICAL PROVISION 11.0

INDIVIDUAL SEPTIC TANK

11.01 Scope of Work

The work covered by this section includes the furnishing of all plant, labor, tools, equipment, and material, and performing all operations in connection with the construction of individual septic tanks, including connection to building (house) drains, solid sewer pipe, cleanouts, abandonment of existing septic tanks, fittings, effluent filters, and appurtenances in accordance with these technical provisions and applicable drawings.

11.02 Permits and Approvals

The Government shall secure the applicable site approvals and sewage disposal permits for the work specified herein.

11.03 Location of Facilities

The location of the facilities specified herein shall be as shown on the drawings and/or as staked in the field by the Project Manager. The Contractor shall not change the designated location of these facilities without the prior approval of the Project Manager.

11.04 Inspection of Installation

In addition to the applicable inspection requirements of the Tribe and/or County, the Contractor shall notify the Project Manager at least 2 working days prior to placing final backfill over the septic tank so that the Project Manager may inspect the installation.

11.05 Solid Sewer Pipe

The Contractor shall install a solid smooth pipe from the septic tank to the building (house) drain. Solid sewer pipe and fittings shall be 4-inch PVC plastic, ASTM 3034, SDR 35 sewer service lines. Installation shall be in accordance with all state and local and/or Tribal standards.

11.06 Effluent Filter

The Contractor shall install in the outlet tee of the septic tank a 1/16th-inch effluent filter cartridge equivalent to Orenco Biotube Residential Septic Tank Effluent Filter or Tuf-Tite EF-4 Residential Series.

The outlet tee in the septic tank shall be of sufficient length to extend one (1) inch below the bottom of the filter cartridge (See detail drawings).

1/06 Technical Provisions TP 11.0 Individual Septic Tank

11.07 Septic Tank

11.07.01 Tank

The tank shall be precast, reinforced, watertight concrete as manufactured by an established firm specializing in concrete products conforming to ASTM 6913. Minimum liquid capacity below the outlet level shall be as specified on the drawing(s) and each tank shall have 2 compartments. The walls, floor & top shall have a minimum thickness of 2 ½-inches. Adequate steel reinforcement shall be provided. Each compartment shall be provided with adequate tees, elbows and baffles. The tank shall meet all state and local standards.

11.07.02 Access Riser

Each compartment of the septic tank shall be provided with a watertight access riser with a minimum dimension of 24-inches for inspection and sludge removal. The access riser on the second chamber shall be centered so as to provide access to the effluent filter. Access risers shall meet all state and local standards. Additional access ports, if required by local health codes, shall be installed by the Contractor at no additional expense to the Government. Risers shall be equal to Orenco systems lids and risers.

11.07.03 Septic Tank Installation

The septic tank shall be set in a hole excavated by the Contractor in accordance with all state and local standards.

11.08 Pump Existing Septic Tank

When included on the bid schedule, the Contractor shall pump existing septic tanks by pumping the liquid and solids out of the tank. The septic tank liquid and solids shall be disposed of as required by local health codes. Backfilling pumped liquid to agitate the accumulated solids in the septic tank is not allowed.

11.09 Abandon Existing Septic Tank

When included on the bid schedule, The Contractor shall abandon existing septic tanks by pumping out the liquid out of the tank, breaking open the cover of the tank, and backfilling the empty tank with approved borrow material. Backfilling shall be carefully placed to eliminate voids, and shall be mounted to allow for settlement. The septic tank liquid shall be disposed of as required by local health codes.

11.10 Underground Cleanout

Where required and as shown on the plans, the Contractor shall install a two-way underground cleanout on the solid sewer line. The cleanout shall have a threaded plug and be constructed as detailed in the drawings. The cleanout shall be extended so that the square nut on the threaded plug is ½-inch below finished ground level. If indicated on the plans, a concrete pad 18-inches square and 4-inches deep shall be poured around each cleanout at the ground surface. This pad shall be reinforced with welded wire mesh with a minimum 1 1/2-inch concrete cover over mesh. The wire mesh shall be ASTM approved W1.4 (1/8-inch) wire mesh on 6-inch center

1/06 Technical Provisions TP 19.0 Gravity Chamber Drainfield

TECHNICAL PROVISION 19.0

INDIVIDUAL GRAVITY CHAMBER DRAINFIELDS

(CONVENTIONAL, STEP-DOWN, AND SAND-LINED)

19.01 Scope

The work covered by this section includes the furnishing of all plant, labor, tools, equipment, and performing all operations for the construction of chamber drainfield for subsurface disposal of effluent from the septic tank, including solid sewer pipe, chamber units, and all other items as necessary to provide a complete and operable installation

19.02 Site Preparation

Prior to installation, the Contractor shall remove all ground vegetation, stumps, and other extraneous material from the construction area of the drainfield, as shown on the drawings, and dispose of it in a manner approved by the Project Manager. Excess excavated soil, if any, shall be removed from the construction site or stockpiled in an area on the property as directed by the Project Manager.

19.03 Materials

19.03.01 Pipe

Solid sewer pipe and fittings shall be 4-inch PVC pipe, conforming to ASTM D3034, SDR 35.

All joints and connections shall be solvent cemented in accordance with the pipe manufacturer's recommendations and shall be watertight.

19.03.02 Chamber Units

Chamber units shall be a minimum 36-inches wide, a minimum 12-inches in height and able to support live loads of 16,000 pounds per axle with 12-inches of compacted fill over them, equal to "Infiltrator" units manufactured by Infiltrator Systems Inc. (203) 388-6639 or approved equal.

Chamber units shall have interlocking joints.

19.03.04 Distribution Box

The Contractor shall install (if required) a distribution box as detailed in the drawings and of sufficient size to accommodate the number and size of lines required. The distribution box shall be constructed of durable, watertight materials, and equipped with a removable cover. The distribution box shall be set on compacted soil or otherwise be supported to prevent misalignment, and it shall provide for equal flow of effluent to all outlets.

A baffle shall be placed in a minimum of2-inches from the inlet, and the inlet invert shall be a minimum of I-inch above the outlet inverts. Each outlet pipe into the distribution box shall be extended at least 3-inches beyond the inside wall of the box and be fitted with a PVC cap. An offset 2 1/2-inch circular hole shall not be glued to the pipe as they.are designed to be used for flow adjustment by rotating them. The Contractor shall install the top of the distribution box level with the ground surface.

19.04 Installation

The solid sewer pipe between the septic tank and distribution box, and between the distribution box and the chamber units, shall be laid in a trench at least 12-inches wide and at a uniform minimum slope of ¼-inch per foot. Care shall be taken to bed the pipe in a material that is free from rocks or otherwise unsuitable material. Backfill shall be compacted by hand from the bottom of the trench to a minimum of8-inches over the top of the pipe for the full width of the trench. A minimum of 18-inches of cover is required over the top of the solid sewer pipe between the infiltration marsh and the distribution pipe.

The chamber drainfield shall be located as shown on the drawings. The Contractor shall excavate to the length, depth, and in the direction specified for the drainfield. All compacted surfaces of the trench shall be raked to expose the natural texture of the soil. All loose material shall be removed from the trench. If unanticipated conditions are encountered in the field which will adversely affect the performance of the drainfield (clay, bedrock, hard pan, groundwater, etc.), the Project Manager shall be notified immediately. Open trenches shall be protected from surface runoff by diversion ditches or other methods.

All chamber drainfield trenches shall be a minimum of 36-inches wide as shown on the drawings. The chamber units shall be placed carefully to avoid damage to the soil, following the manufacturer's recommendations for installation. The bottom of the trench and the drainfield pipe shall be laid level to within plus or minus 0.1-feet.

The chamber drainfield trench shall be carefully backfilled in a manner that will not damage the chamber units. Excavation in excess of backfill requirements shall be spread over the drainfield area. The minimum depth of cover over the top of the drainfield chamber units shall be 9 inches.

If a chamber bed system is required, the chamber units shall be installed side by side, as shown on the site plan.

19.05 Chambered Drainfield Installation for Sloping Sites

When indicated on the drawings and where the site conditions entail predominantly sloping terrain (approximately 15 45% slope) a step-down drainfield shall be installed. The same installation measures shall prevail as in section 19.04. The Contractor shall excavate to the length, depth, and direction specified with the drainfield legs extending laterally across the sloping terrain, following the contours. The total drainfield shall be underground with a minimum of 9-inches of cover. The chambered drainfield laterals shall be connected either in parallel or series, as specified on the drawings, with 4-inch PVC solid pipe.

When specified, a drop-box shall be installed at each lateral leg entrance. The solid 4-inch PVC pipe connections shall allow enough slope for effluent flow from drop-box to drop-box. Drop-boxes shall be accessible from ground surface and fitted with a secure cap.

19.05 Installation for Gravity, Sand Lined Chambered Drainfield

The same installation measures prevail as in section 19.04. Additionally, imported ASTM C-33 sand shall be placed at a two foot minimum depth below the chambers. Drawings shall specify drainfield profile dimensions. If specified by the Project Manager; a Medium Saud (Type 2B) shall be used in place of the ASTM C-33 sand.

The medium sand fill material shall meet the following particle size gradation (Source: ASTM C-33, Specification for Fine Aggregate):

Effective % Passing

Sieve Particle Size by Weight 3/8 inch 9.50mm 100% No.4 4.75mm 95-100% No. 8 2.36mm 80-100% No. 16 1.18mm 50-80% No. 30 0.60mm 25-60% No. 50 0.30mm 10-30% No. 100 0.15mm 2-10%

The sand shall be not more than 45% passing any one sieve and retained on the next consecutive sieve of those shown above.

The fineness modulus shall not be less than 2.3 nor more than 3.1. The fineness modulus is defined as the sum of the cumulative percentages retained in the sieve analysis, divided by 100, for the sieve sizes shown above. Each load of fill sand shall be approved by the Project Manager.

19.06 Site Restoration, Grading, Ditching, and Marking

Site restoration shall be in accordance with TP 3.0. The Contractor will be held responsible for repairing trench settlement problems during the one-year warranty period. Excess excavated soil shall be distributed evenly around the site.

The Contractor shall provide grading and ditching around the completed drainfield to direct the flow of surface runoff away from the drainfield. The exact location of the ditch lines will be determined by the Project Manager the drainfield installation is completed.

The Contractor shall avoid all unnecessary movement of equipment over the completed drainfield.

The Contractor shall use construction stakes and yellow caution tape to visibly mark the perimeter of the completed drainfield area.

19.07 Elevation Control

In order to install the facilities specified herein at the optimum grade and elevation, the Contractor is required to utilize an accurate builder's level and rod, or approved equal, during construction. The level shall be mounted on a tripod and shall be on site at all times during installation.

19.08 Imported Soil

When soil conditions or site topography make it necessary to keep the drainfield and related appurtenances elevated, and when authorized by the Project Manager, it may be necessary to import soil to provide the required minimum cover. The imported soil shall be reasonably clean of rocks, boulders, roots, and otherwise unsuitable materials and shall be approved by the Project Manager prior to placement.

19.10 Submittals

The Contractor shall submit after construction an as-built drawing of the completed site.