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ABSTRACT

Recently, a precast concrete bridge barrier with unique connection details for barrier-to-deck and barrier-to-barrier interfaces was developed at the Institute of Transportation (InTrans)-Iowa State University (ISU) for ABC applications. Successful laboratory quasi-static tests led to the current study, in which the primary objectives were to determine if the new bridge railing system complied with the AASHTO Manual for Assessing Safety Hardware (MASH) Test-Level 4 (TL-4) impact safety standards through a sequence of stages, including pre-crash simulations, one full-scale crash test with a 10000S single-unit truck (SUT), and subsequent post-crash numerical evaluations. Initial analyses incorporated LS-DYNA computer simulations emulating MASH TL-4 impacts on two prototype barrier configurations, i.e., a single-slope shape and a near-vertical shape. These simulations facilitated the discernment of the bridge rail length, reinforcement details, crashworthiness for passenger vehicles, selection of the single-slope shape for crash testing, and determination of a critical impact point for the 10000S SUT crash test. Subsequent modifications to the single-slope barrier system were predicated on these computational findings. A full-scale crash test (test no. ABCBRM-1) assessed the bridge railing and the loading to the inclined steel anchor bars under MASH test designation no. 4-12, focusing on its impact safety performance and potential damage to the barrier and bridge deck. In test no. ABCBRM-1, the 22,200-lb SUT impacted the precast concrete bridge railing at a speed of 55.4 mph and an angle of 14.7 degrees. The SUT was successfully contained and redirected, with the barrier and deck sustaining minimal damage, and all safety performance criteria were within acceptable limits as defined in MASH. Finally, after completing the full-scale crash test, an updated numerical model was developed based on the test data and the results obtained from the pre-crash test simulations. The close agreement between the numerical and experimental results from the post-crash test validated the effectiveness of the numerical modeling approach employed in this project. The study findings demonstrated that the modified single-slope, precast concrete bridge rail system met the MASH TL-4 impact safety criteria.

KEYWORDS

Highway Safety, Crash Test, Compliance Test, AASHTO, MASH, Test Level 4, TL-4, Precast Concrete Bridge Rail, Bridge Deck, LS-DYNA, Computer Simulation, Accelerated Bridge Construction

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