Design and analysis of Annisquam River Bridge railing

Abstract

This paper summarises the design and analysis of the Annisquam River Bridge railing to satisfy the requirements of National Cooperative Highway Research Program (NCHRP) Report 350 Test Level 3. Design of a previously accepted Minnesota Test Level 3 bridge railing was used as the starting point. A baseline finite-element model of a crash-tested Minnesota bridge railing is developed and validated against the full-scale crash test results, using the non-linear dynamic finite-element program LS-DYNA. After validating the baseline model, a series of finite-element simulation studies are performed to evaluate the crashworthiness of six design alternatives. A separate resistance analysis was also performed using the American Association of State Highway and Transportation Officials' Load and Resistance Factor Design (AASHTO LRFD) procedure to verify the adequacy of the final Annisquam Bridge railing design in satisfying NCHRP Report 350 Test Level 3 requirements. Results of the LRFD resistance analysis support the LS-DYNA predictions. This project used a finite-element model that was validated based on a crash test and then used to extrapolate the design to an untested condition. Another novel feature of this research is the comparison of the finite-element-based design in comparison to the AASHTO LRFD procedure. As shown in the paper, the two methods result in essentially identical results. Based on the study results, the Federal Highway Administration (FHWA) issued an acceptance letter allowing the use of Annisquam Bridge railing design on the National Highway System in the United States.