A. The work of this section consists of installing precast concrete toilet and utility buildings including clearing and grubbing, excavating, backfilling, site grading and cleanup.

1.2 QUALITY ASSURANCE

A. Ensure that water on the floor slab drains towards the door.

B. Flush Toilet
1. All plumbing and electrical connections shall be made by licensed plumbers and electricians in the state where the building is installed.

C. Toilet Building Accessibility
1. Ensure that paths within 50 feet of the toilet building are accessible and meet ADA requirements.

1.3 SUBMITTALS

A. Certification from supplier that bedding material meets the gradation specified.

B. If blasting is required for excavation, submit blasting plan.

C. Building installation manual.

DELIVERY AND HANDLING

A. Contractor shall coordinate with the building manufacturer for the delivery and placement of the precast concrete building. Refer to Sections 13120, 13121 or 13122.

B. The Ordering Unit Contracting Officer shall provide detailed directions and a map for each delivery site.

C. Roads and bridges shall be rated for highway loads along the access route. The Ordering Unit Contracting Officer shall verify that the delivery site is accessible by trucks (18-wheeler) with a 48 ft. trailer. If the delivery site is inaccessible the Contractor shall coordinate with the Ordering Unit Contracting Officer for delivery. The Government will pay additional costs.

D. Building shall be installed according to the manufacturer’s installation instructions.

PART 2 – PRODUCTS

2.1 SOIL CLASSIFICATION

A. Excavation shall be unclassified as to materials and shall include all materials that are encountered in the required excavation.

2.2 BACKFILL MATERIAL

A. Backfill material shall be sandy clay, sand, gravel, soft shale, or other suitable material free from brush, organic material, dirt clods, stone or boulders larger than six inches in greatest dimension or frozen material.

B. Backfill within six inches of concrete shall contain no stone larger than two inches and no stone two inches or larger shall lie closer than six inches to the ground surface.

C. Backfill material shall be excavated material whenever it meets specification requirements. Whenever excavated material contains less than 10 percent of oversized material, the Contractor shall remove boulders larger than 6" from the excavated material at no additional compensation and utilize it as backfill material. Whenever material meeting the specification requirements is not available from excavation, the Contractor shall import material from a designated or approved source.

2.3 SELECT BORROW

A. When excavated soil does not meet the requirements for backfill, Contractor shall backfill with select borrow obtained from a source identified by the Ordering Unit Contracting Officer.

2.4 BEDDING MATERIAL

A. Bedding material shall be washed sand or 3/8" minus crushed or screened aggregate from a private or commercial source. Sand or aggregate shall be used as a leveling course beneath the concrete vault or slab.

2.5 ACCESSIBLE PATH SURFACING

A. The Government will provide granular surface material for placement by the Contractor within 50 feet of the building.

2.6 SEALANT

A. For vault toilet buildings, use 100% silicone caulk, clear for vent pipe and toilet riser. GE Silicone II, 800-626-2000, or approved equal.

PART 3 – EXECUTION

3.1 STAKING

A. The Government will establish the finish floor elevation and approximate corners of the building prior to the Contractor beginning work.

3.2 CLEARING AND GRUBBING

A. Clearing and grubbing shall be confined to designated areas and only marked trees may be removed. Maximum clearing and grubbing shall be confined to an area 20 feet beyond the back and sides of the building and 30 feet in front of the building. Construction work shall disturb a minimum of the existing terrain and plant life adjacent to the cleared and grubbed area. The Contractor shall exercise care to not damage unmarked trees and shrubbery. Skinned or barked trees shall be repaired with an application of black asphalt emulsion especially formulated for such use.

B. Trees shall be felled within the clearing limits, usually towards the center, so as to prevent damage to the trees that are to be left standing. When necessary to prevent damage to structures, adjacent trees, property, or to minimize danger to traffic, trees shall be cut in sections from the top downward.

C. All trimming of trees shall be done in accordance with approved horticultural practices. Branches shall be sawed cut flush with the trunk. Stumps within the clearing limit but out of the excavation area shall be cut not more than 6 inches above the ground.

D. Trees and limbs larger than 4 inches in diameter shall be cut in 8-foot lengths and stockpiled as directed by the Ordering Unit Contracting Officer.

3.3 TOPSOIL

A. Topsoil shall be removed from the area to be excavated and from the area where excavated material shall be piled prior to excavating. Topsoil shall be kept separate from excavated material. Topsoil shall be reused on those areas from which it came after backfilling is complete.

3.4 SAFETY, SHORING, AND PROTECTION

A. The Contractor shall meet OSHA safety rules and regulations. Walls of excavations 4’ or more in depth shall be supported by bracing, shoring, or other methods, unless the walls are sloped to a safe angle from the bottom. If shored, the excavation shall be of proper dimensions to accommodate shoring and bracing, as required to keep walls from collapsing and to allow for proper installation of the work. All existing improvements, either on public or private property, shall be fully protected from damage. All supports shall be removed after construction is completed, and shall be withdrawn in a manner that will prevent the collapse of the sides of the excavation. All openings in the ground, caused by the removal of supports, shall be filled with suitable material properly compacted.

B. All excavations left open overnight shall be fenced with wire or plastic mesh secured to steel posts all around the excavation.
1. The bottom of the fence shall follow the contour of the ground
2. Maximum spacing of the steel posts shall be 10 feet
3. Minimum height of the fence shall be 36 inches.

3.5 REMOVAL OF WATER

A. The Contractor shall provide and maintain, at all times during construction, ample means and devices with which to promptly remove and properly dispose of all water entering the excavations or other parts of the work without damage to adjacent property. All excavations shall be kept free from standing water. The Contractor at his own expense shall repair any damage caused by water in the excavation.

3.6 EXCAVATION, BACKFILL, AND SITE GRADING

A. Coordination with the Building Manufacturer
1. Contractor shall coordinate with the manufacturer of the precast concrete building to accommodate installation at the time of delivery. The Contractor shall be responsible to obtain installation instructions from the manufacturer and perform the excavation, backfill, and site grading in accordance with those instructions. The excavation shall be over excavated two feet (horizontal measurement) on each side of the vault or slab to allow for compaction and minor adjustments in orientation. The Contractor must have excavation complete prior to delivery of the precast concrete building. The Contractor will be provided 1-week minimum lead-time to have the excavation work performed. Also, the Contractor must be on site at the time of delivery to perform the backfill operation as soon as the precast concrete building is in place.

B. Excavation
1. Excavation shall be performed by any method approved by the Ordering Unit Contracting Officer. Stockpile excavated material away from the excavation to facilitate crane and delivery truck access. The crane and delivery truck typically need to be side-to-side during placement.
2. Compact the natural ground at the bottom of the vault excavation with a minimum of three passes with an approved whacker-type mechanical tamper.

C. Bedding
1. The Contractor shall place a leveling course prior to placement of the vault or building. Compact leveling course with one pass of an approved whacker-type mechanical tamper. Grade leveling course so there will be no high spots in the middle. Compact with a second pass with a tamper. Slope the top of the bedding one percent from back to front of building.
a) Minimum compacted leveling course for vault shall be 4 inches.
b) Minimum compacted leveling course for building slab shall be 6 inches.

D. Building Placement
1. Refer to Section 13120, 13121 or 13122.

E. Backfill
1. Backfill shall be permitted only after the work to be covered has been approved by the Ordering Unit Contracting Officer. Backfill shall be placed in 8" thick (loose measurement) lifts and compacted with three complete passes of an approved vibratory compactor.

3.7 START-UP PROCEDURES

A. Vault Toilet
1. Vault Preparation
a) Add approximately 80 gallons of potable water to cover the floor of the vault(s).
2. Vent Pipe Installation
a) Install vent pipe plumb and seal around pipe at top and underside of roof with silicone sealant. Seal around pipe at top of slab with silicone sealant.
3. Toilet Riser Installation
a) Apply silicone sealant between toilet riser flange and concrete floor before the riser is installed.

B. Flush Toilet
1. Plumbing Connection
a) Make connections to water and sewer lines in accordance with manufacturer’s instructions.
2. Electrical Connection
a) Make connection to electrical service in accordance with manufacturer’s instructions.

3.8 FINISH GRADING

A. All surfaces and slopes shall be shaped to blend with the original ground line, mounded over or smoothed off, and raked, and left in a uniform and neat condition. Stockpiled topsoil shall be smoothly distributed over disturbed areas and hand raked to blend with ground line. Final grade shall be flush with top of front slab to provide accessibility. Surface drainage shall be diverted so that it will not enter into the area.

B. The surface of accessible paths within 50 feet of the building shall be compacted with 3 passes of a vibratory compactor prior to placement of Government furnished granular material. Place granular surface material and compact with 3 passes of a vibratory compactor, wetting the material between passes.

3.9 CLEANUP

A. After backfilling and grading has been completed, the disturbed area shall be finished to present as near a natural appearance as possible and cleaned up by removing all debris and materials not utilized.
B. Clean building walls, floors, and roof using soapy water.

3.10 DISPOSAL

A. All unsuitable excavated material, oversize boulders, stumps, small limbs, brush, sod and other construction refuse shall be disposed of off-site at a State-approved disposal site.