Emergency scour repairs and performance at the Route 37 viaducts, NJ, USA

Abstract

Route 37 links the New Jersey (USA) mainland to beach communities in Seaside Heights and is an emergency evacuation route. Carrying three lanes of traffic in each direction, the adjacent bridges are approximately 4900 ft (1490 m) long. Following the devastation of Superstorm Sandy in 2012, a special underwater inspection revealed severe scour damage at 23 piers, necessitating emergency scour countermeasures. The worst location suffered 15 ft (4·6 m) of local scour with 10 ft (3 m) of timber pile exposure. A fast-track inspection, analysis and design, expedited client responses, continuous coordination and excellent team cooperation achieved timely repairs to the worst-affected locations, while keeping the bridges open for much-needed access to the barrier island for storm recovery efforts. Emergency repairs included installation of grout-filled fabric formed bags installed in situ around the pile caps as formwork and filling voids beneath the caps with grout. Precast solid armouring blocks were then installed around the toe of the grout bags. These repairs preserved not only the most severely undermined piers, but also provided a resilient, long-term repair. Recent underwater inspections verified the effectiveness of the repairs, which have encouraged material deposition and replenished the natural bay bottom.