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Thesis Defence: Performance-Based Seismic Design of Circular Bridge Piers Reinforced with CSA G30.18 500W.
August 28, 2023 at 9:00 am - 12:00 pm
Sisay Tadele, supervised by Dr. Shahria Alam, will defend their thesis titled [“
Performance-Based Seismic Design of Circular Bridge Piers Reinforced with CSA G30.18 500W.” in partial fulfillment of the requirements for the degree of Master of Applied Science in Civil Engineering.
An abstract for Sisay Tadele’s thesis is included below.
Defences are open to all members of the campus community as well as the general public. Please email shahria.alam@ubc.ca to receive the Zoom link for this defence.
ABSTRACT
Bridge structures are essential components of infrastructure that play a pivotal role in connecting areas with difficult geography, such as across a river. Apart from ensuring ultimate life safety and serviceability limit state performance, their performance during seismic events determines the safety of the user and economic growth of the region. With advancements in technology, new construction materials are being produced. One of the commonly promoted types of new materials in construction is high-strength steel (HSS). The use of HSS for instance has a wide range of applications in construction, from reducing bar congestion to increasing workability and reducing labor as well as construction costs. Nonetheless, the use of HSS has been restricted, or no guidelines are available in many cases for the design of seismic-resistant members.
In this study, the performance of CSA G30.18 500W is evaluated to study its suitability for the seismic design of reinforced concrete bridges. This study involves extensive experimental research work involving material tests of the HSS reinforcing steel and large-scale reinforced concrete bridge pier tests to assess the performance of the material. The examinations of low-cycle fatigue were conducted with various bar sizes, unsupported lengths, and strain amplitudes. Notably, the CSA G30.18 500W exhibited satisfactory low-cycle fatigue performance, wherein the effect of bar unsupported length and strain amplitude were more pronounced. Additionally, two large-scale bridge piers were tested under seismic loads to study the performance of the reinforced bridge columns, which are the location of plastic hinges in bridges and undergo large inelastic deformation. The test results of the columns indicated that the bridge piers achieved comparable drift levels and energy dissipation capacities with columns reinforced with regular steel ASTM A706 Grade 420. Moreover, the strain limits for performance-based design (PBD) of bridges utilizing CSA G30.18 500W were derived from the measured material strain limits. Lastly, a comparative study of the seismic performance of bridge piers containing ASTM A1035 Grade 690, CSA G30.18 400W, and CSA G30.18 500W was conducted through fragility curve analysis.
