Hillis-Carnes was contracted to perform Subsurface Exploration and Geotechnical Engineering services for the proposed construction of a three-story,100,000 SF addition to the northeastern side of the existing Walt Whitman High School. The site was partially occupied by the Whittier Woods Elementary School building which was razed prior to the new construction. The proposed addition was to predominantly be utilized for classrooms. Due to existing site grades, the first floor of the proposed addition was located at approximately the same elevation as the second floor of the existing high school building.

Hillis-Carnes performed geotechnical engineering services, which included exploring site and subsurface conditions for the proposed building along with site suitability for infiltration for Stormwater management purposes and interpreting these conditions in relation to the proposed project. To characterize the behavior of the existing soil and groundwater conditions at the site as it pertains to foundation design and related geotechnical aspects for proposed development, nine (9) Standard Penetration Test (SPT) soil borings to depths of 20-30 feet below existing site grades were drilled and tested. An additional five (5) borings to depths of 15 feet below existing site grades in the proposed SWM facility areas were drilled and tested, along with five (5) infiltration test borings for the SWM locations.

Laboratory tests were then be performed as necessary to establish the significant characteristics and parameters of the subgrade soils. Based on the boring results, recommendations for foundation support systems, including a recommended soil bearing pressure and footing subgrade preparation was provided to the client, as well as recommendations on slabs on grade, drainage, compacted fill, and any other related geotechnical aspects in relation to the proposed construction.