I-95 Bridge Over Cottman Avenue Emergency Repairs

On June 11, 2023, a tanker truck loaded with flammable fuel crashed and caught fire on the Interstate 95 bridge over Philadelphia’s Cottman Avenue. The bridge collapsed, and all lanes of I-95 were closed. This shutdown of a crucial major interstate caused severe congestion in and around Philadelphia, and disrupted supply chain traffic throughout the Northeastern US. Schnabel’s geostructural team was called in to help.

The affected section of I-95 had an average daily traffic count of nearly 160,000 vehicles, including  about 13,000 trucks. State and federal authorities promised swift measures to mitigate the economic repercussions and reduce inconvenience.

The quickest short-term solution identified: create a temporary embankment fill on the underlying roadway so multiple lanes of I-95 could be reopened while the existing abutments were evaluated and a new bridge was reconstructed on the outer lanes. To allow six lanes of traffic, a 74-foot-wide section of I-95 needed to be backfilled in the middle, spanning a 103-foot-long gap in the highway. Mechanically stabilized earth (MSE) walls measuring 20 feet tall were needed to place the embankment and allow construction activities on either side.

Ultra-lightweight foamed glass aggregate (UL-FGA) was selected as the backfill material to help accelerate the transportation of 8,000 cy of fill to the site, allow construction to take place 24/7, and minimize vertical pressure on the existing subgrade and utilities under the road.

Schnabel’s geostructural group performed the design of the temporary MSE wall using wire baskets and geogrid backfilled with foam glass aggregate made from recycled glass. Our team worked diligently to deliver complete design drawings in one business day to PennDOT, allowing construction to begin immediately after bridge demolition and removal. This allowed PennDOT to reopen the bridge to traffic in under 12 days.

Photo: © Elevated Angles LLC