Laderman Memorial Bridge

The Laderman Memorial Bridge, built in 1970, is 7,294’ long and 104’ wide, consisting of a total of 51 spans, with 46 spans containing some form of Fracture Critical Member (FCM) . The bridge is comprised of twin parallel structures spanning over the Passaic River and carries three (3) lanes of traffic in each direction.  The structure crosses over four (4) major rail lines, two (2) highways, five (5) ramps; and, it passes under the Pulaski Skyway. The Bridge is subjected to the highest volume of truck traffic of any bridge in the New Jersey Turnpike Authority (NJTA) inventory. The bridge framing system includes spans with a girder-floorbeam-stringer configuration, as well as, multi-stringer arrangements. Over the years, the Laderman Memorial Bridge has  experienced extensive fatigue cracking at numerous structural details. To better understand the structural behavior, mitigate the existing fatigue cracks and prolong the service life of the bridge, the NJTA engaged Arora to perform a detailed investigation to identify the causes of the cracking and develop retrofit measures. As part of a multi-faceted approach to this engineering challenge, which included Structural Health Monitoring (SHM) of stresses due to frequent heavy live loads, and, a comprehensive Weigh-In-Motion (WIM) study to accurately determine the types, sizes, weights and frequencies of truck traffic traversing the bridge,  Arora developed a series of global and detailed 3-D Finite Element models to reproduce analytically field measurements. Based on the findings, Arora developed a Fatigue Retrofit Program  for the Bridge.