Scope_of_Work_03032015.pdf

Scope of Work Water Retention Pond

Oroville Border Station Oroville, WA March 3, 2015

1.1 Project Description:

A. Contractor shall provide all labor, materials, tools and equipment necessary for excavation, grade work, and construction of a precast modular block (PMB) retaining wall structure and other requirements in accordance with these specifications and Drawing C101 at the Oroville Border Station, Oroville, WA.

1.2 Performance Period:

A. The performance period for this contract shall be 90 calendar days from contract award to substantial completion. The Contractor shall commence all non-physical construction requirements of this contract; to include submittal of bonds and/or insurance documents, background investigation documents (as applicable), and material submittals within 15 calendar days after contract award. Notice to Proceed will be issued by the Contracting Officer upon acceptance by the GSA of all required documents, submittals and receipt of Security clearances. Physical work shall only be allowed after the issuance of Notice to Proceed.

B. Final completion shall occur no later than 15 calendar days after substantial completion.

Final completion includes, all site cleanup activities, punch list items, and closeout documents (see 1.4 Submittals).

1.3 Work Specifications:

A. Contractor shall excavate work area for leveling pad/footings for new concrete retaining wall units.

1. The leveling pad shall be constructed in accordance with manufacture’s recommendation to provide a level, hard surface on which to place the first course of precast modular block units. The leveling pad and backfill requirements shall be designed by the retaining wall block manufacture. Contractor may provide a. or b.

below depending on manufacture’s recommendation.

a. Crushed Stone Leveling Pad. 5/8” minus crushed stone shall be placed in uniform maximum lifts of 9 inches. The crushed stone shall be compacted by a minimum of 3 passes of a vibratory compactor capable of exerting 2,000 lbs. of centrifugal force.

b. Unreinforced Concrete Leveling Pad. The concrete shall be placed in the same dimensions as those required for the crushed stone leveling pad. The retaining wall installation contractor shall erect proper forms as required to ensure the accurate placement of the concrete leveling pad according to the retaining wall construction drawings.

i. Concrete used for construction of an unreinforced concrete leveling pad shall satisfy the criteria for AASHTO Class B. The concrete shall be cured a minimum of 12 hours prior to placement of the precast modular block wall

Oroville Border Station retaining units and exhibit a minimum 28-day compressive strength of 2,500 psi.

B. Precast Modular Block Wall System Installation

1. Wall assembly shall have a 30’ interior radius, 9’ high, with ramp way sidewalls as shown on drawing C101.

2. The first course of block units shall be placed with the front face edges tightly abutted together on the prepared leveling pad at the locations and elevations shown on the construction drawings. The retaining wall installation contractor shall take special care to ensure that the bottom course of block units are in full contact with the leveling pad, are set level and true and are properly aligned according to the locations shown on the construction drawings.

3. Backfill shall be placed in front of the bottom course of blocks prior to placement of subsequent block courses. Backfill detail shall be designed by the retaining wall block manufacture. Nonwoven geotextile fabric shall be placed in the V-shaped joints between adjacent blocks. Drainage aggregate shall be placed in the V-shaped joints between adjacent blocks to a minimum distance of 12 inches behind the block unit.

4. Drainage aggregate shall be placed in 9 inch maximum lifts and compacted by a minimum of three (3) passes of a vibratory plate compactor capable exerting a minimum of 2,000 lbs. of centrifugal force.

5. Nonwoven geotextile fabric shall be placed between the drainage aggregate and the retained soil (gravity wall design) or between the drainage aggregate and the reinforced fill (reinforced wall design) as required on the retaining wall construction drawings.

6. Subsequent courses of block units shall be installed with a running bond (half block horizontal course-to-course offset). With the exception of 90 degree corner units, the shear channel of the upper block shall be fully engaged with the shear knobs of the block course below. The upper block course shall be pushed forward to fully engage the interface shear key between the blocks and to ensure consistent face batter and wall alignment. Drainage aggregate, geotextile and properly compacted backfill shall be complete and in-place for each course of block units before the next course of blocks is stacked.

7. The elevation of retained fill shall not be less than 1 block course (18 inches) below the elevation of the reinforced backfill throughout the construction of the retaining wall. This requirement shall not apply to unreinforced, gravity wall designs.

C. Construction Tolerance. Allowable construction tolerance of the retaining wall shall be as follows:

1. Deviation from the design batter and horizontal alignment, when measured along a 10

ft. straight wall section, shall not exceed ¾ inch.

2. Deviation from the overall design batter shall not exceed ½ inch per 10 feet of wall height.

Oroville Border Station

3. The maximum allowable offset (horizontal bulge) of the face in any precast modular block joint shall be ½ inch.

4. The base of the precast modular block wall excavation shall be within 2 inches of the staked elevations, unless otherwise approved by GSA.

5. The maximum allowable vertical displacement of the face in any precast modular block joint shall be ½ inch.

6. The wall face shall be placed within 2 inches of the horizontal location staked.

D. Wall infill and reinforced backfill placement

1. Backfill material placed immediately behind the drainage aggregate shall be compacted as follows:

a. 95% of maximum dry density at ± 2% optimum moisture content per ASTM

D698 standard proctor or 80% relative density per ASTM D4254.

b. Compactive effort within 4 feet of the wall face should be accomplished with walk-behind compactors. Compaction in this zone shall be within 93% of maximum dry density as measured in accordance with ASTM D698 standard proctor or 75% relative density per ASTM D 4254. Heavy equipment should not be operated within 4 feet of the wall face.

c. Backfill material shall be installed in lifts that do not exceed a compacted thickness of 9 inches.

E. Precast modular block retaining wall units.

1. All units for the project shall be obtained from the same manufacturer and installed in accordance with manufacture’s recommendations. If the manufacturer has been producing retaining wall units of this precast modular block system for less than five

(5) years, provide quality control compliance documentation for the precast modular block system.

2. Concrete used in the production of the precast modular block units shall not consist of returned, reconstituted, surplus or waste concrete. It shall be an original production mix meeting the requirements of ASTM C94 and exhibit the following:

a. Minimum 28-day compressive strength of 4,000 psi.

b. Shall be free of water soluble chlorides and chloride based accelerator admixtures.

c. Maximum water/cement ratio of 0.50 for mild climate areas and 0.45 for moderate or severe climate areas as defined in ASTM C94 and ACI 211.1 Section 6.3.3.

d. Air-entrainment in conformance with ASTM C94 Table 1.

e. Maximum slump of 5 inches +/- 1½ inches per ASTM C143 for conventional concrete mix designs.

f. Slump Flow for Self-Consolidating Concrete (SCC) mix designs shall be between

18 inches and 32 inches as tested in accordance with ASTM C1611.

g. Each concrete block shall be cast in a single continuous pour without cold joints.

With the exception of half-block units, corner units and other special application units, the precast modular block units shall conform to the nominal dimensions

Oroville Border Station listed in the table below and be produced to the dimensional tolerances shown as measured in accordance with ASTM C140.

Block Type

Dimension

Nominal Value

Tolerance

28” Block Height 18 inches +/- 3/16 inch Length 46-1/8 inches +/- 1/2 inch Width 28 inches minus 1”

41” Block Height 18 inches +/- 3/16 inch Length 46-1/8 inches +/- 1/2 inch Width 40-1/2 inches +/- 1 inch

60” Block Height 18 inches +/- 3/16 inch Length 46-1/8 inches +/- 1/2 inch Width 60 inches +/- 1 inch

h. Basis of design is Redi Rock precast concrete modular block with grey cobblestone face. Contractor may submit other products but they shall meet or exceed the requirements of 1.3 E.

F. Landscaping and sprinkler requirements-Exterior side of wall

1. Contractor shall protect existing sprinkler system from damage.

2. Contractor shall grade the area on the exterior of the new wall to a smooth surface with gradual slopes to allow for lawn mowing. Provide compacted fill as required.

Finished grade shall be 6” below the top of the wall.

3. Contractor shall provide and install a new electric valve connected to the existing sprinkler control and water supply and shall provide and install all piping, risers, and sprinkler heads (Rainbird gear driven roter, or equal) to provide full sprinkler coverage for disturbed areas on the outside perimeter of wall. All materials used shall be commercial grade designed to this application. All piping shall be installed at a minimum depth of 18”

4. Contractor shall provide and install sod in all disturbed areas on the exterior side of the wall.

G. Landscaping-interior of walls

1. Grade all interior surfaces smooth. Remove grass, weed, and debris.

H. Concrete ramp access into water retention pond

1. Contractor shall provide and approximately a 9’ wide x 6” thick concrete access ramp to the retention pond at location shown on drawing C101, for removal of future silt, etc. Concrete shall be installed on a 4” compacted gravel base, and shall have Grade 40 6” x 6” reinforcing mesh installed in accordance with manufacture’s recommendations.

a. Concrete shall provide a uniform tamped surface to provide traction.

I. Drainage piping

Oroville Border Station

1. Contractor shall provide all labor and materials to extend the existing (2) drain pipes

(approx. 8”) located at the north end of the retention pond into the NW run off concrete baffle assembly.

J. Chain link fence

1. Contractor shall provide and install 8’ high chain link fence to match existing at locations shown on drawing. Provide and install 10’ gate with locking mechanism for access to the ramp area. All fencing and piping shall be commercial grade and installed in accordance with manufacture’s recommendation.

K. Runoff water concrete baffle assemblies and high water overflow

1. Contractor shall move or replace water run off baffle assemblies to align within walls.

Provide piping as required. Any damage shall be repaired by the contractor.

2. High water overflow assembly shall be replaced with new assembly. Provide shop drawing for approval.

1.4 Submittals:

A. Material submittals shall be provided to the Government no later than (NLT) 15 calendar days after award of contract. All submittals shall be accompanied by a completed GSA Submittal Transmittal Form (see attached). Clearly mark material submittals to identify which products and options are applicable to this contract (this is especially important with product data in which multiple items and/or optional items are provided for on the same sheet). The rejection of a submittal by the GSA COR (General Services Administration Contracting Officer’s Representative) is not sufficient reason to extend the contract performance period. Upon GSA COR acceptance of submittals, the GSA Contracting Officer (CO) will issue notice to proceed (NTP) to the Contractor. The actual Construction Period available to the Contractor will vary depending on the amount of time taken to complete the bonds, background investigations, and material submittal process. Allow 10 (ten) calendar days for review and approval of all submittals.

Contractor shall provide submittals and receive approval prior to ordering materials.

1. Project schedule

2. Precast Modular Block System brochure/technical data and proposed layout

3. Manufacture’s engineered foundation layout and backfill requirements shop drawing

4. Geotextile manufacture’s technical data sheet

5. Retaining wall contractor qualifications

6. Manufacture’s data for chain link fencing and gate

7. Shop drawing for high water overflow assembly

8. Closeout documents upon completion to include:

a. Warranties

b. Payroll Documentation (certified payrolls, SF1413s, etc.)

c. Final invoice and payment support documents.

d. Release of Claims

Oroville Border Station

1.5 Security:

A. All workers shall pass a background screen prior to the start of the work in accordance with Security requirements in the contract.

1. The GSA Project Manager will provide the successful offeror with a partially completed electronic Contractor Information Worksheet (CIW) and OF 306 (samples attached). Paper copies of CIW’s will not be accepted. The CIW is required in MS Word document (Version 4 12/2010), and encrypted. Scanned pdf documents will not be accepted.

a. Submit the CIW and OF 306 electronically to r10securityem@gsa.gov CIW’s shall be completed entirely including the GSA sponsor of the adjudication and all contract information. (Vendor name, contract #, award date, end date)

b. Form OF 306 shall be completed and submitted

2. Contractor fingerprints will be taken electronically at any of the USAccess/Managed Service Office shared credentialing centers. Once our security office receives a validated and legible CIW, the information from the CIW will be entered into GSA’s database, and then the contractor will be sponsored. Once sponsored, the contractor will be able to go on-line and make an appointment at any shared service credentialing office to get their fingerprints taken. Use the following website to locate shared credentialing centers: http://www.fedidcard.gov/centerlocator.aspx

3. All security information shall be submitted no later than 7 calendar days after contract award notice.

4. All workers shall display at all times the ID badge issued to contractors by the GSA.

5. All workers shall confine operations to areas permitted.

1.6 Specification Compliance Requirements:

A. Code and Design Standards:

1. The Contractor shall secure all permits and certifications to comply with all federal, state, local codes and design standards, latest editions, to include but not limited to:

a. International Building Code (IBC, International Code Council)

b. Occupational Safety and Health Administration (OSHA) Code of Federal

Regulations Part 1910 and Part 1926.

c. Facility Standards for the Public Building Service, PBS/P-100

(2010): http://gsap100.wbdg.org/

d. OSHA safety regulations:

https://www.osha.gov/law-regs.html

1.7 Material Compliance Requirements:

A. Reserved

1.8 Recycling Requirements:

A. Reserved

Oroville Border Station

1.9 Additional Project Requirements:

A. Contractor use of premises:

1. No waste shall be put in building dumpsters or containers.

2. On-site storage is not available except in area of work.

3. All persons working for or under a General Contractor or Sub-Contractor shall maintain safely marked areas of work.

4. The building tenants shall have no functional disruptions resulting from the contractor’s planning and execution of project work.

1.10 Work Hours:

A. All work shall be performed between the hours of 6 am and 7 pm Monday through Friday unless approved otherwise by GSA.

1.11 Clean-up:

A. The contractor shall install protective measures to protect existing conditions and to contain dust and debris during construction to ensure a safe and irritant free work environment for site occupants.

1. Work shall provide for protection of all existing site finishes, and shall include cleanup of work site during and after work performed. Work shall include removal of all unused material, refuse and debris from the area of work.

a. Dispose of all construction debris according to Federal, State and Local requirements.

B. If site surfaces are damaged, contractor shall repair to original condition.

1.12 Attachments:

1. Drawing C101

2. Submittal Transmittal Form

3. Sample Contractor Information Worksheet (CIW)

4. Sample OF 306 Declaration for Federal Employment