Seismic Design and Evaluation of Concrete Bridges and Buildings

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The research program involves two main areas with two projects on earthquake engineering and two projects on the performance of concrete infrastructure. Research will be carried out on the seismic performance of bridges to assess the newly developed seismic design provisions of the 2014 Canadian Highway Bridge Design Code. Methods for predicting damage levels in bridge columns due to different levels of earthquakes will be developed to assist bridge designers in carrying out the new performance-based design procedures. The goal is to provide a design approach that is not only concerned about preventing collapse but also minimizing damage for smaller, more frequent seismic events. Reversed cyclic loading experiments will be carried out to study ways of predicting damage indicators for deficient existing bridge structures and analytical tools for predicting the extent of possible damage will be developed. This Discovery Grant is aimed at improving the safety of older bridges that were designed before proper seismic design procedures were available and will also provide an assessment of likely damage for different levels of earthquakes. This research will advance the state of knowledge in predicting the seismic response of new as well as existing bridges and will lead to improvements of the seismic design provisions of the Canadian Highway Bridge Design Code. Studies on the effects of foundation rotation on the seismic response of buildings will be carried out to gain an understanding of the complex soil-structure interaction that takes place. The aim of this research program is to account for the effects of the increased flexibility of shear walls due to the rotations of the foundations at the base of the walls. With the aid of non-linear finite element analysis and reversed cyclic loading tests of full-scale beam-column-slab sub-assemblies, the reinforcement details and shear reinforcement required in joints of lower ductility frame members will be developed to assess suitable requirements for the CSA Standard A23.3 on the Design of Concrete Structures. These types of frames are common in eastern and central Canada and yet there is little information on the effects of the detailing of these frame members. These two research projects will advance the understanding of the effects of foundation rotation and the seismic response of frames of moderate and low ductility. This research will result in improvements to the CSA Standard for the Design of Concrete Structures. Design and detailing requirements for achieving ductile columns when using ultra-high-strength concrete will be developed for use in high-rise construction. The confinement reinforcement must be effective to provide a ductile response after sudden cover spalling occurs. The use of self-consolidating concrete with steel fibres will also be investigated as a means of partial replacement of confinement reinforcement in ductile columns. This would result in a workable concrete mix with the added benefit of the fibres and has the possibility of reducing the congestion in ductile columns. This research will advance the state of knowledge on the performance of these new types of concrete and will provide practical solutions for the confinement of columns. The use of drilled-in anchors used to provide shear reinforcement in thick slab concrete bridges to avoid shear failures will be investigated and the effects of deterioration due to alkali-silica reactivity on the shear strength will be investigated. Ways of preventing progressive collapse in parking garage structures affected by corrosion of the reinforcement and delamination will be studied. These two studies are aimed at preventing failures in existing deteriorated bridge and parking garage structures.