THE CONCRETE BRIDGE MAGAZINE

SPRING 2018

ASPIRE is a quarterly magazine published by PCI in cooperation with the associations of the National Concrete Bridge Council. The editorial content focuses on the latest technology and key issues in the Concrete Bridge Industry.

Issue link: http://www.aspiremagazinebyengineers.com/i/957336

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PROJECT NEW JERSEY ROUTE 72 — Eastbound Over Manahawkin Bay Bridge by Joseph Mumber, David Rue, and Steve Esposito, WSP, and Pankesh Patel, New Jersey Department of Transportation Owned and maintained by the New Jersey Department of Transportation (NJDOT), the causeway carrying New Jersey Route 72 over Manahawkin Bay is the only access from the New Jersey mainland to the beach communities of Long Beach Island (LBI), an 18-milelong coastal barrier island. LBI is home to 20,000 year-round residents in six separate municipalities. During the peak summer tourist season, the population swells to more than 150,000. Therefore, a safe, reliable, and resilient highway connection is essential for residents and visitors, as well as for the local economy. Resilience Needed By the early 1990s, many of the fatigue-sensitive details in the existing steel stringer-floorbeam bridge, which was designed in the 1950s, had failed or were failing. NJDOT considered the following alternatives for this critical corridor: total replacement of the bridge; providing dual structures by building a new parallel bridge for one direction and rehabilitating the existing bridge for the other direction; and rehabilitation. To satisfy NJDOT’s desire for resiliency, the dual-structure alternative was selected. The new concrete superstructure is designed to offer distinct advantages over the older design by eliminating the fatigue-prone details. Also, when coupled with the superstructure replacement of the existing bridge, the new, parallel eastbound structure provides operational redundancy in the corridor. If either bridge needs to be closed for any reason (such as hurricane, earthquake, or vessel impact), the other structure will be adequate to carry both directions of traffic. This approach was validated in 2012, when Superstorm Sandy made landfall near Brigantine, N.J., causing widespread damage to the state’s infrastructure. Although the structures on Route 72 were not severely damaged, the storm did cause scoured conditions at several locations, and NJDOT maintenance stabilized the affected structures by installing riprap. The scour design was updated for the project to prepare for hurricane-strength storm-surge conditions suggested in the post-Sandy Federal Emergency Management Agency flood insurance study for the project area. Hydraulic models were updated to include new fathometer survey information that accounts for poststorm conditions. The new bridge was designed to withstand the predicted scour depths without countermeasures. Articulated concrete block mattresses were incorporated to protect the existing bridge’s scoursensitive abutments, and the existing piers were found to be stable for the design storm. Other Design Features The new structure was designed to accommodate two lanes of traffic in the eastbound direction, while the existing bridge will carry two lanes westbound once the rehabilitation is completed in 2019. The eastbound structure is 2400 ft long and 52 ft 9.75 in. wide, with six lines of prestressed concrete girders made Profile NEW JERSEY ROUTE 72 EASTBOUND OVER THE MANAHAWKIN BAY / STAFFORD TOWNSHIP AND BOROUGH OF SHIP BOTTOM, OCEAN COUNTY, NEW JERSEY BRIDGE DESIGN ENGINEER: WSP Inc., Lawrenceville, N.J. PRIME CONTRACTOR: Schiavone Construction Co. LLC, Secaucus, N.J. PRECASTER: Bayshore Concrete Products, Cape Charles, Va.—a PCI-certified producer

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