Concrete_SOW_revised.docx

Concrete Sump Installations And Two Concrete Tanks

The Bozeman Fish Technology Center (USFWS) is installing an experimental flume used in fish passage research. The flume is a long, fiberglass channel which is end-capped by two concrete, rectangular tanks. Significant concrete work is required to collect and divert water flows as well as house various species of fish. The contractor will field verify and coordinate with FWS Bozeman Fish Technology Center existing conditions, placement of the new concrete tanks and any other relevant conditions and questions in the execution of the project.

The concrete work will be accomplished in two phases:

1. Form in-place a concrete sump in an existing raceway floor.

2. Form in-place two, above ground, concrete tanks.

The concrete and reinforcement used in both phases will conform to the following standards:

-Cement shall be standard brand Portland cement conforming to ASTM C 150 –Portland Cement, for Type I/II or Type V.

-Concrete Properties (The Contractor is cautioned that the limiting parameters are not a mix Design).

Min 28 Day Compressive Strength, psi 4,000 Max Aggregate Size, in 0.75 Max Allowable Fly Ash Content (FA); lbs/cubic yard Up to 150, (i.e up to 25% max of cement content) Max W/C Ratio by weight 0.45 Total Air 3 to 6

Content, percent

reducer 7-in +/- 2-in)

- Finishing Concrete Surfaces:

1. General: Surfaces shall be free from fins, bulges, ridges, offsets, honeycombing, or roughness of any kind, and shall present a finished, smooth, continuous hard surface.

2. Formed Surfaces: No treatment is required after form removal except for curing, repair of defective concrete, and treatment of surface defects.

3. Surface holes larger than 1/2-inch in diameter or deeper than 1/4-inch are defined as surface defects in basins and exposed walls.

4. Unformed Surfaces: After proper and adequate vibration and tamping, unformed top surfaces of slabs, floors, walls, and curbs shall be brought to a uniform surface with suitable tools.

-Treatment of Surface Defects:

1. As soon as forms are removed, exposed surfaces shall be carefully examined and any irregularities shall be immediately rubbed or ground in a satisfactory manner in order to secure a smooth, uniform, and continuous surface. Plastering or coating of surfaces to be smoothed will not be permitted. No repairs shall be made until after inspection by the USFWS staff. In no case will extensive patching of honeycombed concrete be permitted.

2. Concrete containing minor voids, holes, honeycombing, or similar depression defects shall be repaired with a non-shrink grout. Concrete containing extensive voids, holes, honeycombing, or similar depression defects shall be completely removed and replaced. Repairs and replacements shall be performed promptly.

3. For both phases the Contractor shall provide reinforcement steel, accessories, and appurtenant work, complete and in place. Shop drawings shall be provided for reinforcement steel, showing the details of the reinforcement steel which shall conform to ACI 315. Shop drawings shall include the following items:

a. Bending diagrams. The shop bending diagrams shall show the actual lengths of bars to the nearest inch measured to the intersection of the extensions (tangents for bars of circular cross section) of the outside surface.

b. Placement diagrams. Include bar placement diagrams. These diagrams shall also clearly indicate the dimensions of splices and where they occur.

c. Bar Quantities. The quantity of bars shall be identified for each bar configuration.

PHASE ONE:

The Bozeman Fish Technology Center (USFWS) requests a concrete sump be installed in the bottom of an existing fish-raceway concrete floor per the drawings near the south tank. This sump is to be used as a water collection vessel as well as a high-volume pump station. In order to install this sump, there will be substantial concrete cutting, removal and soil excavation. The concrete will have sufficient strength and factor of safety to withstand fully saturated surrounding ground conditions. Temporary shoring will be required.

The concrete floor is roughly 60 yrs. old with thickness unknown. The concrete floor is approximately 4.5 feet below grade. Underground utilities are unexpected; however, there is a possibility of undocumented, past construction dating back to the 1880’s.

Groundwater at the site is expected to fluctuate seasonally and may be encountered upon excavation. The contractor shall furnish, install, maintain, and operate all necessary pumping and other equipment for removal of water from the various parts of the work, and for maintaining the excavated walls, foundations, trenches and other parts of the work free from water as required for constructing each part of the work. The contractor is responsible for obtaining and complying with the conditions of any required dewatering permits. Drill logs and locations from a 1995 geo-technical report are attached.

Following is a list of specifications required and drawings sufficient to complete Phase One.

Specifications for Phase One

1. Concrete saw-cut dimensions and excavation will be minimized with temporary shoring but be able to provide all necessary space for concrete forms and other project excavation requirements. All over-excavated areas will be re-filled with soil and topped with concrete. Over-excavation soil will be compacted to 95% of maximum density per ASTM D698 and any over-excavated original concrete replaced with new concrete for a smooth transition to the sump.

2. The finished inside dimensions of the sump will be 20’ long x 8’ wide x 10’ deep.

3. The sump will consist of 24” thick floor and 12” thick walls per the drawings.

4. The concrete used will contain the water-proofing additive (Masterlife 300D by BASF) or equivalent.

5. There needs to be a slight slope to the sump floor for complete de-watering.

6. The use of a hydrophilic water stop is required at the junction of the sump floor and sump walls. Additionally, the use of a water stop is required between all separate pours.

7. 2” x 2” fiberglass grating must be purchased and installed as a sump cover by the contractor. The fiberglass grating should be of molded construction with a non-skid surface (McNichols MS-S-200 or equivalent). All necessary supports to provide a stable, non-sag platform must be provided by the contractor. Supports must be made of aluminum or stainless steel. Galvanized or zinc coated materials will not be allowed in this construction.

8. All metallic construction materials not fully embedded in concrete must be aluminum or stainless steel.

9. An overflow weir 6” deep X 3’ wide must be formed in the sump wall adjacent to the existing water trough per drawings.

10. All excavated material and concrete must be disposed of by the contractor.

11. Existing chain link fence to be removed and reinstalled as necessary. Care must be taken to protect adjacent asphalt surface.

Drawings for Phase One

PHASE TWO:

The Bozeman Fish Technology Center (USFWS) requests two concrete tanks to be formed and poured on-site. The smaller, north tank is a simple rectangular tank with an outflow channel (water depth controlled by dam boards). The north tank also has an attachment point (channel) for the upper end of the fiberglass flume. The larger, south tank has three compartments to be used for water diversion and energy dissipation as well as fish holding.

Each channel (except the flume attachment points) will have two opposing 2” wide by 2” slots. These slots will accommodate the use of dam boards and/or fish screens. The concrete used will contain the water-proofing additive (Masterlife 300D by BASF) or equivalent. This will be added during the batch process at the ready-mix source plant. The concrete tanks will also require aluminum splash guards on four of the outflow channels (per drawings). All Channel dimensions are as follows:

North Tank Flume Channel 54” X 36” (approximate) East Outflow 54” x 24”

South Tank Flume Channel 60” x 36” (approximate) NE Outlet 70” x 36” SE Outlet 70” x 36” S Outlet 70” x 36” Inner Wall Channels (x2) 70” x 36”

1. The use of a hydrophilic water stop is required at the junction of the tank floors and tank walls. Additionally, the use of a water stop is required between all separate pours.

2. All metallic construction materials not fully embedded in concrete must be aluminum or stainless steel.

3. The floors of the tanks will follow the existing slope –allowing for complete de-watering of the tanks during winter months.

4. Anchor bolt holes and flume channel (red dashed area on image below) to be field fit on-site using existing flume dimensions with station project manager.

5. For final acceptance of the project, the floors and walls of both tanks must be clean, deburred, and paint ready, concrete surface must be rubbed or ground to remove surface defects.

6. All unused concrete will be disposed of by the contractor at an approved facility.

Drawings for Phase Two (for reference only; please refer to the stamped drawing set for all construction activities).

*For Reference Only* image6.jpeg image7.emf image8.emf image9.emf image10.png image11.png image12.png image13.png image14.png image1.png image2.png image3.png image4.jpeg image5.jpeg