Donnelly Wash Low Flow Crossing at Florence-Kelvin Highway, Pinal County, AZ

New Construction: The project scope consists of the following tasks: The project is located on the Florence-Kelvin Highway at the Donnelly Wash Crossing approximately 17 miles east of State Route 79 just southeast of the scenic recreational area known as “The Boulders” in Township 5 South, Range 12 East, Section 15 of Gila River Base and Meridian, Pinal County, Arizona. The Scope of Work consists of constructing a five cell 10-foot by 4-foot box culvert and a six cell 10-foot by 4-foot box culvert, both crossing north and south underneath the Florence-Kelvin Highway at Donnelly Wash; erosion protection along the east and west side of the gabion mattress adjacent to the box culverts; installation of a guardrail along the deck assembly; and other related work as shown on the approved drawings. Site Preparation: The areas to be occupied by the proposed roadway construction or structures should be stripped of all vegetation, debris, rubble and obviously loose surface soils. The silty fine sand soils may be sensitive to excessive moisture content and will become unstable at elevated moisture content. Accordingly, it may be necessary to compact soils on the dry side of optimum, especially in asphalt pavement areas. The reduced moisture content under slabs-on-grade should only be used upon approval of the engineer in the field. The bottom of the box culvert foundation will be located ~1 foot below the channel that will remove some of the loose channel fill. That loose fill may have changed due to recent and/or future flooding events. A representative of the geotechnical engineer or qualified agency inspector should examine the subgrade once sub-excavation (if any) is complete and prior to placement of new foundations or aggregate base to ensure removal of deleterious materials and proper bearing conditions. If loose soils are discovered during the construction process, partial removal (up to 4 feet based on borings) or deepening of the foundations may be required to uncover the medium dense soils. The fill placement and quality should be as defined in the “Fill and Backfill” section of the Technical Provisions & Specifications report. Attention must be paid to provide proper drainage to limit the potential for water infiltration of deeper soils. Prior to placing structural fill or the aggregate base, the exposed grade should be scarified to a depth of 8 inches, moisture conditioned to optimum (±2 percent) and completed to at least 95 percent of maximum dry density as determined by ASTM D-698. A CWA section 404 permit has been obtained from the US Army Corps of Engineers for this project. Adherence to the terms of the permit is required, including preconstruction notification and limiting construction activity to Construction Limits shown on the approved drawings. Unless accepted by the Engineer, work on this project shall be started within 10 calendar days from the notice to proceed date and be completed within one hundred and eighty (180) calendar days from notice to proceed date. Deadline for questions is October 1, 2021 by 5:00pm. Bonds