UBC Theses and Dissertations
Performance based design and evaluation of reinforced concrete bridges Zhang, Qi
Performance based design (PBD) has been deemed as one of the most promising design methods in the past few decades. It reduces the uncertainties underline the tradition force based design (FBD) and acts as an efficient communication tool between technical and non-technical people. Canadian Highway Bridge Design Code (CHBDC) has initiated PBD in Canada in 2014, which brought in one of the biggest changes to the new version of the design code. For Lifeline bridges and irregular Major Route bridges, the code requires PBD to be used to explicitly demonstrate structural performance. As per the code, Regular Major Route bridges can be designed by using either FBD or PBD method. In this study, a multi-bent concrete highway bridge is designed using both FBD and PBD based on CHBDC 2014, and FBD based on CHBDC 2006. The evaluation of different designs is performed to determine which method is more conservative. Soil-structure interaction is incorporated using p-y method in the design and analysis. Dynamic time-history analyses are performed to assess the seismic performance. The assessment is based on the maximum strain limits from CHBDC 2014. The results reveal that the PBD in CHBDC 2014 is highly conservative in comparison with FBD in current and previous design codes. This is because CHBDC 2014 requires rebar yielding shall not happen at 1/475-year earthquake event. Eliminating rebar yielding at 1/475-year event may be very challenging to achieve in high seismic regions and 1/475-year event may dominate other design levels. After performing the PBD, a displacement based design approach is also used to examine the performance criteria from the code. It is shown that by using displacement based approach the PBD could be simplified for regular bridges. Additionally, a series of charts of column drift versus steel strain are presented to facilitate future engineering designs. At the end, the methodology of the next generation PBD is utilized to compare the seismic performance of bridges in terms of engineering demand parameters and decision variables.
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Attribution-NonCommercial-NoDerivs 2.5 Canada