The Staten Island bridge carries I-278 WB and EB over Mosel Avenue and service roads and over State Island Rapid Transit Railway (SIRT) and service road. Each of the crossings at Mosel and SIRT currently consist of three-span structures. The new construction is a single span structure over Mosel Avenue and a single span structure over SIRT. The key requirements of the geotechnical program were to assess the geotechnical parameters for the pile geotechnical design as well as the bearing capacity and settlement of the MSE wall.

Geotechnical borings and cross hole testing were performed. Data from the cross-hole testing were used to define the site class but more importantly to assess the settlement of the fill beneath the abutment together with laboratory soil compressibility test results.

Following the exploration program, OEI submitted a Geotechnical Data Report (GDR) followed by a Foundation Design Report. The LRFD was adopted in the all the analyses except the settlement where service loads will be utilized. Standards in the NYSDOT Design Manual were used. The integral abutments were supported on micropiles. Estimate of downdrag forces was a key geotechnical issue. Other geotechnical issues were estimates of differential settlement beneath the MSE walls. The micropiles were installed within the MSE wall.