Wiebe, RichardKnight, Henry2023-08-142023-08-142023-08-142023Knight_washington_0250O_25369.pdfhttp://hdl.handle.net/1773/50289Thesis (Master's)--University of Washington, 2023Lateral instability in long-span prestressed concrete girders during handling, transportation, and construction can result in disruptive, damaging, and even deadly failures. Historically, the predominant instability mechanism in these girders has been buckling in the form of a rigid-body roll combined with lateral bending. As increasingly longer bridge spans are designed, their girders become more susceptible to lateral stability issues and, notably, see increased twisting deformations—which have frequently been neglected in lateral stability analysis during transportation and handling. This work will include the effects of torsional deformations, strong-axis bending, prestressing deflections, overhangs, and imperfections in developing closed-form buckling loads and equilibrium paths for lateral instability. From these buckling loads, it will develop and test closed-form models that can predict the lateral stability behavior and equilibrium angle of a long-span girder under different applied loads. This work seeks to robustly characterize the instability mechanisms of girders during transportation and handling. It incorporates the effects of, and the interactions between, torsional deformations, strong-axis bending, prestressing deflections, overhangs, imperfections, and cracking to predict buckling loads and equilibrium paths that describe lateral instability. In the pre-cracking regime (which is often preferred by design) it develops and evaluates closed-form models that can predict the lateral stability behavior and equilibrium angle of a long-span girder under different applied loads. For post-cracking behavior, a computational model was developed and compared to previous results in the literature. This model was then used to conduct a parametric study to determine which prestressed concrete girder design parameters most impact the onset of cracking, post-cracking stiffness, and ultimate failure angle. This information about cracking was combined with the closed-form buckling equations to propose a new design procedure for prestressed concrete girder lateral stability that works for both uncracked and cracked girders. This procedure was used to explore trends in long-span girder design, and to identify potential limiting parameters that could control the maximum designable length of present-day girder cross sections.application/pdfen-USnoneBucklingConcreteCrackedLong-SpanPrestressedStabilityCivil engineeringCivil engineeringThesis