Bridge No. 65 Replacement (Lake Co., Indiana)

CLIENT: Lake County

Clark Dietz provided design and construction monitoring services for the replacement of Bridge No. 65 in Lake County. The existing beam bridge sat within a sharp roadway curve that significantly limited vehicle speeds. Our team designed an underfill structure, which carries the roadway on fill placed over the structure, to accommodate the curved alignment and allow vehicles to safely travel through the curve at 30 mph.

Site investigations revealed a significant foundation challenge: a 25-foot-deep deposit of marly silt beneath the proposed structure. These soil conditions required the team to reconsider the planned foundation and develop a solution that would adequately support the replacement.

Clark Dietz changed the design from a traditional spread footing to a pile-supported footing, transferring structural loads to deeper supporting soils. Detailed foundation and pile analyses helped refine the design and reduce the amount of piling required.

Our team also worked with the County to identify additional funding sources to address the added work associated with the difficult soil conditions. During construction, Clark Dietz monitored the work to verify that the structure and foundation were built as designed.

By adapting the foundation design and supporting the County’s funding needs, Clark Dietz helped deliver a replacement suited to both the roadway’s curved alignment and the site’s challenging ground conditions.