This research project, “Dynamic Bridge Substructure Evaluation and Monitoring,” was sponsored by the Federal Highway Administration (FHWA) under contract number DTFH61-96- C-00030. The... More > research was funded to investigate the possibility that by measuring and modeling the dynamic response characteristics of a bridge substructure, one could determine the condition and safety of the substructure and identify its foundation type (shallow or deep). Determination of bridge foundation conditions with this approach may be applied to quantify losses in foundation stiffness caused by earthquake, scour, and impact events. Identification of bridge foundation type may be employed to estimate bridge stability and vulnerability under dead and live load ratings, particularly for unknown bridge foundations. Chapter 2 introduces the research project scope and presents the results of a literature review of related topics. Chapter 3 describes the bridges in Texas that were selected for modal vibration tests during the research.< Less
For many years, engineers have designed foundations, walls and culverts for highway and other applications using allowable stress design (ASD) methods. In ASD, all uncertainty in loads and material... More > resistance is combined in a factor of safety or allowable stress. For most highway design, the American Association of State Highway and Transportation Officials (AASHTO) Standard Specifications for Highway Bridges represents the primary source document for ASD of substructures. In 1994, AASHTO approved Load and Resistance Factor Design (LRFD) in the LRFD Highway Bridge Design Specifications. In LRFD, the uncertainty in load is represented by a load factor and the uncertainty in material resistance is represented by a resistance factor. Due to the fundamental differences between the substructure design process by ASD and LRFD, this course has been developed to present the fundamentals of LRFD for the geotechnical design of highway bridge substructures.< Less
Many bridges along the Gulf Coast were damaged by recent hurricanes, and many more are susceptible to similar damage. This research examines the structural performance of common connections used to... More > anchor prestressed concrete girders to the substructure. Full-scale specimens were fabricated and tested under static and dynamic cyclic load histories. Dynamic load histories were developed from previously conducted hydraulic tests of a 1/5 scale model of a highway bridge under hurricane wave loads. Load effects considered included the pseudo-statically applied vertical uplift force, horizontal force, combined horizontal and vertical forces, and dynamically applied combined horizontal and vertical forces.
Structural performance of the details under these loading conditions is examined. This allows improved understanding of connection performance, enables better design for new bridge construction and for rehabilitating existing bridges to resist hurricane loads.< Less
Many bridges along the Gulf Coast were damaged by recent hurricanes, and many more are susceptible to similar damage. This research examines the structural performance of common connections used to... More > anchor prestressed concrete girders to the substructure. Full-scale specimens were fabricated and tested under static and dynamic cyclic load histories. Dynamic load histories were developed from previously conducted hydraulic tests of a 1/5 scale model of a highway bridge under hurricane wave loads. Load effects considered included the pseudo-statically applied vertical uplift force, horizontal force, combined horizontal and vertical forces, and dynamically applied combined horizontal and vertical forces.
Structural performance of the details under these loading conditions is examined. This allows improved understanding of connection performance, enables better design for new bridge construction and for rehabilitating existing bridges to resist hurricane loads.< Less
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