Modeling and validation of full scale crash testing for open-faced aesthetic concrete barrier

As bridges built in the 1930’s and 1940’s begin to reach the end of their design and service lives, the concrete and embedded steel reinforcement of balustrades show noticeable signs of deterioration, which affects their performance. Many of these old bridges are historic and the aesthetics must be preserved to keep it as a historic landmark. The Historic Preservation Office (HPO) mandated that a new balustrade for use on historic bridges must retain the appearance of the original one while also satisfying the requirements of the crash test level AASHTO MASH TL-4, which was adopted by the FHWA on January 1, 2011. This study addresses the issue that the state of New Jersey does not currently have any open-faced balustrade standard specifications. A new design was developed, for which the aesthetics have been approved by the HPO, and a detailed finite element model was developed using LS-DYNA software for crash test simulation. The capacity of the barrier was checked using the design procedures outlined in section 13 of the AASHTO Bridge Design Specifications. A parametric study of the balustrade was performed using the finite element model, adjusting parameters such as height, post width, and window opening width. Occupant risk factors such as ridedown accelerations, and occupant impact velocities were evaluated using these models. Based on the results of the simulations, a final design was selected and chosen for full scale crash testing. A single unit truck, pickup truck, and small passenger car were crash tested at TTI and successfully met all the AASHTO MASH TL-4 requirements. All risk factors were well below the maximum permissible values for the car and pickup truck, and the single unit truck was successfully contained. After these successful crash tests, the model was calibrated to more accurately duplicate the impact response of the vehicle and barrier. The models were also validated using traditional methods, as well as the statistical comparison program, Roadside Safety Verification and Validation Program (RSVVP), which was developed under NCHRP Project 22-24.M.S.Includes bibliographical referencesby Andrew Wagdy Wasse