Agmt17 Cal Engineering & Geology, Inc.

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TASK 1 — CONCRETE CORING Contractor shall coordinate with a concrete coring and reinforcement steel scanning subcontractor to collect 8 concrete cores as follows: a. Sawcut out one 18 inch long piece of vertical rebar. The rebar will be tested for its tensile yield and ultimate strength. The rebar will be obtained from near the top of a wall panel in a section that already has permanent lateral bracing. The sawcuts will be approximately 6 inches deep and made between adjacent vertical rebar elements to minimize impact to the channel wall. b. Core drill two 4 inch diameter cores near the base of wall at a wall panel that is P/2 inches out of plumb at the top of wall. One core with rebar and one core without rebar will be obtained. The core with rebar will be visually inspected to determine rebar corrosion and the remaining effective area of the rebar will be measured with a caliper. The core without rebar will be used to determine concrete compressive strength. c. Core drill two 4 inch diameter cores near the base of wall at a wall panel that is approximately 3 inches out of plumb at the top of wall. One core with rebar and one core without rebar will be obtained. The core with rebar will be visually inspected to determine rebar corrosion and the remaining effective area of the rebar will be measured with a caliper. The core without rebar will be used to determine concrete compressive strength. d. Core drill two 4 inch diameter cores near the base of wall at a wall panel that is approximately 5 inches out of plumb at the top of wall. One core with rebar and one core without rebar will be obtained. The core with rebar will be visually inspected to determine rebar corrosion and the remaining effective area of the rebar will be measured with a caliper. The core without rebar will be used to determine concrete compressive strength. e. Core drill one 4 inch diameter core without rebar from the foundation (channel invert) in a section that already has permanent lateral bracing. The core will be tested for concrete compressive strength. Contractor shall select core locations based on the above criteria and perform scans to determine the location of reinforcing steel. Concrete compressive strength cores will be located adjacent to steel core samples approximately 4 feet away. Prior to commencing the coring operation, Contractor shall temporarily brace the channel walls near the location of the coring to maintain stability of the wall panels during coring as required. Jacks shall be installed such that a load will not be placed on the walls in a manner that could potentially cause damage to the existing creek structure. Once coring is complete the jacks shall be released slowly until the wall segments appear to be stable. If the wall segments begin to deflect as the jacks are removed, then the braces will remain in place until a more permanent solution can be provided. Contractor shall furnish, install, and remove all necessary jacks required for the destructive concrete tests under this contract. REV: 02-10-17 PR Page 7 of 9 ATTY/AGR.2017.034/Cal Engineering & Geology, Inc.