NV5 teamed with CH2M Hill to provide design services for the replacement of Retrac Road Bridge over Wolf Creek, a federally funded Highway Bridge Program (HBP) project. Our services included performing a geotechnical subsurface investigation to provide engineering design recommendations for earthwork and structural improvements.
The investigation was performed following the guidelines and reporting requirements of Caltrans’ Foundation Report Preparation for Bridges. NV5 prepared recommendations that included design parameters for foundation types and embedment depths, allowable soil bearing capacity, foundation soil friction coefficients, retaining wall lateral earth pressure coefficients, and seismic design parameters.
Project challenges included resistant rock on the west abutment and resistant boulders in highly weathered granitic rock on the east abutment. The bridge abutments will consist of a spread footing on the west side and drilled shafts on the east side. We elected to use smaller diameter drilled shafts to more efficiently penetrate the resistant boulders.