Book Description

The objectives of this portion of the project were to: 1) determine if any or all of the three subject variants of the 32-inch (813 mm) Jersey safety shaped bridge railing comply with the requirements of the AASHTO LRFD Bridge Design Specifications and National Cooperative Highway Research Program (NCHRP) Report 350 Test Level 4 (TL4), and 2) provide recommended retrofit schemes, if deemed technically and economically feasible, to bring into compliance the railings that do not comply. Full or partial replacement schemes may also be recommended as appropriate. The most direct approach for accomplishing the objectives of this task was to perform a full-scale crash test of the most critical design. If that railing performed satisfactorily, the railing would be acceptable by AASHTO LRFD Specifications. The strength test was selected, NCHRP Report 350 test 4-12, a single-unit van-type truck weighing 17,6211b (8000 kg). The TL-4 vehicle is a single-unit box-van truck impacting the railing at 15 degrees and 49.7 mi/h (80 kmIh). While containment is required, overturning of the vehicle is an acceptable test outcome. However, Test Level 3 (TL-3) is a 4405-lb (2000 kg) pickup impacting the railing at 25 degrees and 62.2 mi/h (l00 kmIh). This test requires both containment and stability, and non-overturning. Since some breakage of the parapet is possible, potential for vehicle snagging is likely. Vehicle snagging can contribute to vehicle instabilities in the redirection sequence and potential rollover. Therefore, researchers chose both TL-4 and TL-3 tests. According to the results of this project, no field retrofits or replacements of the Florida Jersey safety shaped bridge rails, depicted in the Florida DOT Index 799, are warranted since the most critical 32-inch (813 mm) Jersey safety shaped bridge railing complied with the requirements of the AASHTO LRFD Bridge Design Specifications and NCHRP Report 350 Test Levels 3 and 4.