| Summary: | A Master of Science thesis in Civil Engineering by Zeinah Mohamad Elnassar entitled, “Effect of Vehicle-Parapet Collision Forces on Bridge Girders, Bracings, and Support Bearings”, submitted in June 2022. Thesis advisor is Dr. Sami Tabsh. Soft copy is available (Thesis, Completion Certificate, Approval Signatures, and AUS Archives Consent Form). To account for the load effect due to vehicle collision with the parapet, the American Association of State Highway and Transportation Officials (AASHTO) Bridge Design Specifications contain provisions that ensure structural safety of the parapet and overhang portion of the deck slab. However, AASHTO does not consider the effect of such force on the girders, cross bracings, and supports. Lack of available literature on the subject necessitates the need to investigate the effect of this action on the structural elements that are part of the load path. In this investigation, parametric studies utilizing the finite element method on typical short and medium span composite steel girder bridges subjected to loads on the parapet are conducted. The variables that are addressed in the analysis are the length of parapet segments along the bridge, deck slab thickness, height of parapet, bridge span length, slab overhang width, number of girders, span continuity, and presence/spacing/configuration of bracings. Two types of static structural analyses are conducted, linearly elastic and nonlinear. Findings of the study showed that the bridge response obtained through 3D finite element analysis is complex in nature due to distortion induced by unsymmetrical loads and support conditions. Vertical loads due to vehicle-parapet impact forces affect the flexural stresses in the exterior girders much more than the interior girders, particularly for bridges that have few girders and are not adequately braced. The spacing of bracings and slab thickness highly impact the internal forces developed in bracing members as a result of vertical and lateral loads. The reaction components at the ...
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