DAVID EVANS AND ASSOCIATES (3) - Laserfiche WebLink

Home Browse Search

Proposal to provide Landscape Architectural Design services for loth and Flower Park— RFP No. 22-124 ■ Review existing geology/geotechnical reports for properties in the vicinity. ■ Stake/mark the boring locations in the field so that drill rig access to all the locations is available. In case, the site has existing underground utilities, a representative from the city MUST clear the boring locations, Converse will not be liable for damage to any unmarked utility. ■ Notify Underground Service Alert (USA) at least 48 hours prior to field exploration to clear the boring locations of any conflict with existing underground utilities. Subsurface Exploration: Our subsurface exploration will consist of drilling exploratory borings. The purpose of the borings will be to Obtain subsurface information at the site, Obtain undisturbed and bulk samples of the various soil types for laboratory testing, and record depth to bedrock or groundwater (if encountered). Borings: We will drill 6 borings between 5.0 and 30.0 feet below existing ground surface (bgs) within the project site. If refusal is encountered before the planned depths are reached, the borings will be terminated at that depth. The borings will be drilled with a truck -mounted (CME 75 or equivalent) rig equipped with an 8- inch diameter hollow -stem auger for soil sampling. Relatively undisturbed ring and bulk samples of the subsurface soils will be obtained at frequent intervals in the borings. The undisturbed samples will be obtained with a California Modified Sampler (2.4-inch inside diameter and 3.0- inch outside diameter) lined with thin sample rings. The soil will be retained in brass rings (2.4 inches in diameter and 1.0 inch in height). The central portion of the sample will be retained and carefully sealed in waterproof plastic containers for shipment to our laboratory. Bulk soil samples will be collected in plastic bags and brought to our laboratory. Borings will be backfilled with soil cuttings. The mechanically driven hammer for the sampler is 140 pounds, falling 30 inches for each blow. The number of successive drops of the driving weight ("blows") required for each six inches of penetration will be shown on the boring log. The borings will be backfilled with cement grout (if ground water is encountered) and soils cuttings and compacted by pushing down with augers. Where asphalt concrete is penetrated, the surface will be patched with cold mixed asphalt concrete. It is possible the surface may settle over time. If construction is delayed, we recommend the owner monitor the boring site and backfill any settlement or depression that might occur or provide protection around the area of the boring locations to prevent trip and fall injuries from occurring near the area of any potential settlement. Environmental Analytical Testing for Soil Sample: One composite soil sample from the excess soil cuttings will be submitted to a California ELAP certified laboratory under chain -of -custody control. All sample analyses will be conducted on a standard turnaround time. The samples will be analyzed as follows: ■ EPA 8015M — TPH carbon chain speciation ■ EPA 8260 — VOCs and Oxygenates ■ EPA 8270 — SVOCs ■ EPA 8082 — PCBs ■ EPA8081A—OCPs ■ EPA 6010E — Title 22 metals (TTLC) Waste Disposal: All excess soil cuttings will be contained in five (5) drums. The drums will be temporarily stored on the site away from drainage areas and secured from unauthorized entry until laboratory analytical results are received. The waste will be profiled for the most cost-effective disposal or recycling option. For budgeting purposes, we have assumed five (5) drums of waste will need to be transported and disposed of as non -hazardous waste. Converse will be responsible for the preparation of waste manifests, and for arranging for proper transportation and disposal of the waste. A Client representative will be responsible for signing the manifests as the Generator. Copies of the manifest will be provided. Percolation Test: The purpose of the Infiltration test will be to obtain water infiltration rate of the surface soils at the location of surface runoff discharge. We will conduct infiltration testing at one location. The depth of the infiltration test will be at 10.0 feet bgs. A 2-inch diameter perforated PVC pipe will be installed inside the 10 1 February 28, 2023 1 David Evans and Associates, Inc.