Extreme flooding in the area caused a sinkhole along the shoulder of I-280 eastbound at Milepost 7.8, just east of Exit 7, causing the right lane and shoulder to be closed immediately. A 48” CMP culvert underneath the roadway, built in the 1950’s, collapsed as a result of the sinkhole. Prior to the roadway closure, a truck trailer was initially lodged in the sinkhole. The 48” CMP carried flows from nearby private properties and township roadways. The interstate highway drainage is a separate system that runs west along the embankment and discharges into the stream.
McCormick Taylor managed the emergency response efforts of the team and began designing the repair immediately. The sinkhole was temporarily filled with stone to allow for contractor equipment and machinery to cross over it. Some additional temporary work included:
- Designing and installing a temporary bypass drainage system, which included two pumps. One pump was used to divert the highway drainage from the upstream inlet into the headwall area, while the other was used to divert the water from the headwall to the 36” RCP running along the toe of the EB embankment.
- Designing a supported excavation pit with a 17’x10’ opening and 28’ depth at the location of the sinkhole to access the culvert and further assess the damage.
McCormick Taylor is evaluating more permanent design alternatives to repair and stabilize the roadway, effectively convey the drainage runoff to the stream, and prevent additional flooding to private properties. The team will also perform an H & H analysis of the existing drainage systems and the proposed design alternative. Once an alternative is selected construction will begin.
