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REPORT <br />To the Honorable Mayor and City Council <br />From the City Manager <br /> <br />March 26, 2018 <br /> <br />SUBJECT <br />Increase funding for the National Guard Armory Building Parking Lot Improvements <br />Project to address unforeseen soil conditions <br /> <br />RECOMMENDATION <br />By motion, approve, and authorize the City Manager to increase the amount of the <br />contract with Silicon Valley Paving, Inc. by an additional 10%, if necessary, up to 20% of <br />the $401,379 amount originally awarded, thereby increasing the contract amount to a <br />total of $481,654.80 <br /> <br />BACKGROUND <br />On July 27, 2015, the City Council approved a lease with the State of California at the <br />National Guard Armory located in Red Morton Park. The lease allowed for the use of <br />the Armory building for community recreation purposes. In lieu of monthly lease <br />payments, the City agreed to complete facility and land improvements, including <br />(among other improvements) the re-paving of the back “motor pool” parking lot and the <br />construction of a new, 20,000 square foot publicly used parking lot on the existing dirt <br />lot adjacent to the Armory building. This new parking lot is adjacent to the proposed <br />Magical Bridge Playground at Red Morton Park and will serve as additional parking for <br />the park users. <br /> <br />Improvement plans for the construction of the new parking lot were prepared and the <br />project went out for public bids in the fall of 2017. On November 13, 2017, the project <br />was approved and awarded to Silicon Valley Paving, Inc. of San Jose, with a contract <br />amount of $401,379.00, plus a 10% increase if necessary, for a total of $441,516.90. <br />Construction began in late January, 2018. <br /> <br />ANALYSIS <br />During the course of excavation, the contractor discovered that the existing underlying <br />soils were made up of a sticky, heavy clay that is highly expansive when it encounters <br />water. The soil also takes longer to dry than other soils found within Redwood City. <br />Compaction testing of the soil demonstrated that with standard compaction techniques, <br />the soil was only able to achieve around 80% compaction, when 95% compaction is <br />generally required under paved surfaces. The low compaction was largely due to the <br />moisture content of the soil. The soil was scarified (broken up and turned over to <br />expose more surface area) and allowed to dry over a 4-day period, and still was unable <br />6.1.C. - Page 1