The behaviour of open spandrel brickwork masonry arch bridges (OSBMAB) was studied through model tests and finite element simulations. One three-metre and two five-metre span, full scale OSBMAB were constructed and tested to destruction. Two `partial' models including a combination of spandrel arches and piers, and a five-metre span single arch were also tested with intention of studying the functions of the components of the OSBMAB. To simulate the behaviour of the brickwork masonry arches, three finite element modelling techniques were developed: - (a) smeared modelling method (SMM), in which the failure of brickwork masonry caused by tensile cracking, compressive crushing or sliding is simulated as "loss of stiffness" in the corresponding directions within the domain of the geometry of the arch structure; and (b) discrete modelling method (DMM), in which the failure of brickwork masonry caused by tensile cracking or sliding is simulated as the change in the geometry of the arch structure, i. e., the geometrical discontinuity at prescribed locations; and (c) the mixed modelling method (MMM), in which the main arch, spandrel arches/piers are modelled using the SMM, and the interfaces between the fill and arch are modelled using the DMM. Parametric studies were carried out to investigate the effects of changes in material properties and finite element model related parameters on the behaviour of the OSBMAB, and to justify the values of those parameters adopted in the finite element models using the FE Package ANSYS 5.3. The comparisons were made between the finite element results and those obtained from the model tests. It has been demonstrated in terms of the ultimate loads, the modes of failure and the responses of loads vs. displacements that FE modeling can give good correlation.

Corrosion of the reinforcing steel is a primary deterioration mechanism for reinforced concrete bridges. Heavy use of de-icing salts is believed to be a major contributor in Ontario to severe girder soffit spalling in certain cases. This thesis develops an assessment methodology to evaluate spalled bridges based on ultimate limit states. Specifically, a deterministic program is developed for assessment. It is subsequently compared to laboratory test results and used as a basis for a probabilistic reliability study. A modified area concept is proposed in this thesis to consider the effects of exposing reinforcement at various locations along the girder length. A multipoint analysis program, BEST (Bridge Evaluation Strength Tool), is developed that employs this concept, along with graphical spalling surveys and structural drawings, to evaluate reinforced concrete bridge girders. The program is adapted for a full bridge analysis and to consider the other effects of corrosion, such as bar section loss and bond deterioration. A case study bridge is evaluated to show that the BEST program offers a viable tool for the rapid assessment of spalled bridge girders and to facilitate the prioritization of rehabilitation projects. This evaluation indicates that the spatial distribution of the spalling along a girder, relative to bar splices and laps, has the most significant influence on structural capacity. Single girders show strength deficiencies in flexure and shear due to spalling. In general, the consideration of system effects improves the predicted bridge condition, while considering section loss and bond deterioration has the opposite effect. Laboratory work is used to validate the proposed model and identify a number of areas for future research. The laboratory test results also suggest that the current repair methods are effective in restoring bond and strength. In order to further explore potential uses for the BEST program, modifications are made so that it can be used to perform reliability analyses using Monte-Carlo simulation techniques. A simplified approach for estimating the reliability index as a function of the deterministic resistance ratio is proposed based on the reliability analysis results.

Highway bridges function as the arteries of our society. Hence, it is essential that they remain operational following an earthquake. Unfortunately, a significant number of bridges worldwide, including in Canada, were constructed prior to the development of modern seismic design provisions. In many cases, such bridges are expected to perform poorly during earthquakes. According to a report published in 2000 by Ministry of Transportation of Ontario (MTO), in eastern Ontario alone, there are over 70 bridges that are structurally deficient. Current methods to retrofit these bridges to bring them into compliance with the existing codes would entail substantial structural modifications. Examples of such modifications include the replacement of existing rocker bearings with elastomeric bearings, structural strengthening of piers, and enlarging the bearing surfaces. These methods involve substantial cost, effort, and materials. An alternative means to retrofit structurally deficient bridges is investigated in this thesis. This method involves using a combination of elastomeric bearings and fluid dampers to retrofit highway bridges. In principle, these devices work in the same way as shock absorbers in automobiles. They absorb shock and dissipate the vibration energy to the environment as heat. In the case of bridges, earthquakes impart the shock to the structure. Before these devices can be implemented in practice, there are many issues that need to be understood with respect to their performance and modelling. Moreover, a comparative assessment between popular retrofit options employing isolation systems needs to be undertaken to verify and provide a benchmark to assess their performance. The Mississippi River Bridge near Ottawa is chosen as a test structure to conduct this study. This bridge already contains an advanced isolation system, and has an extensive documentation available for modelling and verification. Various retrofit options will be studied and compared with the existing isolation design for this bridge. In all cases, the effect of soil-structure interaction is included. A comprehensive set of performance indices are used to evaluate the performance of various retrofit options. All the models are constructed in the open source software, OpenSees. The research demonstrates that the proposed approach is a viable retrofit method for highway bridges. Moreover, compared to advanced isolation systems, retrofit using elastomeric bearings with viscous dampers was successful on transferring lower loads to the substructure, and resulted in lower superstructure displacements. Though this study involved one bridge, it has provided a computational test bed to perform further studies and has provided valuable insight into the modeling and performance of retrofit solutions.

Thesis (M.S.)--Auburn University, 2008. / Abstract. Includes bibliographical references (p. 187-189).

Thesis (M. Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 105-107).

Thesis (M.Sc.)--University of Hong Kong, 2000. / Includes bibliographical references (leaves 105-107) Also available in print.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 61-70). Also available via the Internet.

Thesis (Ph. D.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 191-204). Also available on the World Wide Web.

Thesis (M.S.)--University of Wisconsin, 1962. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 29-31).

Gussets plates are used in truss structures to connect multiple members. It is for this reason that it is important that the gusset plate have adequate strength to transfer forces between members, otherwise a failure in a gusset plate can cause the entire truss structure to fail. This study will focus on a gusset plate that is believed to have been under designed on the I-35W Minneapolis bridge. Three possible sources of failure will be investigated: yielding of the gusset plate, fracture of the gusset plate, and buckling of the gusset plate. Various sources such as the plans for the truss and an interim report on its failure will be utilized to construct the model for the finite element analysis. The results obtained from the finite element analysis and the traditional analysis approach using uniform force method will be used to investigate the failure of the gusset plate.