Lightweight Design Alternative for I-95 Reconstruction in Philadelphia

摘要

A section of Interstate 95 in Philadelphia, Pennsylvania, was to be widened, requiring new construction of abutments, wing walls, and retaining walls. The overburden consisted of surficial soft/loose alluvium overlying very dense sands and gravels. Jet grouting ground improvement was initially specified to provide acceptable performance of shallow foundations for the proposed structures. However, the relatively small work zones and close proximity to adjacent structures would be problematic for jet grouting operations. An alternative design which featured lightweight cellular concrete backfill was subsequently developed. The premise of the design alternative was to provide a structure that was light enough to minimize vertical deformation and yet heavy enough to provide overturning and sliding resistance required for adequate stability. This paper discusses the developed methodologies used in the design alternative, construction of the design alternative, and results of a settlement monitoring program.