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Performance-based seismic design and assessment of concrete bridge piers reinforced with shape memory alloy rebar

University of British Columbia

Recent advancements in numerical analysis and computational power have pushed the current bridge design specifications towards a more descriptive performance-based seismic design (PBSD) approach as compared to the conventional force-based method. One major attributes of this PBSD is to keep bridges operational and reduce the repair cost by limiting the global and local deformations of a bridge to acceptable levels under design loads. Shape memory alloy (SMA), with its distinct superelasticity, shape memory effect and hysteretic damping, is a promising material for the application in bridge piers to attain the objectives of PBSD. The objective of this research is to develop a performance-based seismic design guideline for concrete bridge pier reinforced with different types of SMAs. With the aim of providing a comprehensive design guideline, this study started with the experimental investigation of bond behavior of smooth and sand coated SMA rebar in concrete using pushout specimens. The test results were explored to evaluate the influence of concrete strength, bar diameter, embedment length, and surface condition. In addition, a plastic hinge length expression for SMA-RC bridge pier was developed which can be used for calculating the flexural displacement capacity and design of SMA-RC bridge pier. Using Incremental Dynamic Analysis (IDA), this study developed quantitative damage states corresponding to different performance levels (cracking, yielding, and strength degradation) and specific probabilistic distributions for RC bridge piers reinforced with different types of SMAs. Based on an extensive numerical study, the author proposed residual drift based damage states for SMA-RC pier. Based on the proposed damage states, a sequential procedure for the performance-based design of SMA-RC bridge pier is developed using a combination of residual and maximum drift. Finally, in order to elucidate the potential benefit and applicability of the proposed guideline, fragility curves and seismic hazard curves for different SMA-RC bridge piers are developed considering maximum and residual drift as engineering demand parameters. It is found that the SMA-RC bridge piers designed following the proposed design guideline have very low probability of damage resulting in a lower annual loss which will provide significant financial benefit in the long run.

Text

2015-08-27

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/54668

Civil Engineering

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/2.5/ca/