24-0018 Parking Lot 3 100 Design Analysis REVISED.pdf

This document is a Design Analysis and project submittal for the construction of a new parking lot expansion at Offutt Air Force Base in Nebraska. The project (SGBP 24-0018, Contract FA4600-22-D-0003) involves constructing Parking Lot #3, B1000, an asphalt pavement expansion to the south and east of an existing parking lot designed to accommodate 232 additional parking stalls. Key design elements include a uniform 9-inch asphalt pavement thickness throughout, concrete curb and gutter installation, drainage infrastructure with curb inlets tied to a hydrodynamic separator, lighting matching existing facilities (to be provided by OPPD), and pedestrian access paths. The geotechnical investigation identified lean clay and loess soil conditions, with a pavement design generated using the PCASE computer program. Recommended pavement thickness is 9.5 inches to match existing lot performance and improve uniformity.

The project includes two bid options: a Base Bid for 160 parking stalls expanding southward with a construction cost of $1,165,356, and an Alternate Bid for the full 249-stall expansion westward and southward with a cost of $1,998,395 (project budget is $4,400,000). The design analysis addresses storm drainage requirements, with calculations demonstrating that the detention pond has adequate capacity to accommodate the 4 percent increase in runoff from the proposed expansion at the 10-year, 50-year, and 100-year storm events. Construction documentation includes geotechnical exploration and laboratory testing results, meeting minutes from 35%, 65%, and 90% design reviews, and associated review comments and responses addressing parking configuration adjustments, electrical specifications, pavement details, and site preparation requirements.