Seismic performance evaluation of multi column bridge bent retrofitted with different alternatives

• Main Author: Billah, Abu Hena MD Muntasir
• Language: English
• Published: University of British Columbia 2011
• Online Access: http://hdl.handle.net/2429/38250

Highway bridges constitute a large portion of the national wealth and build up the foundation for economic development. Due to aging and deterioration, they require regular monitoring, evaluation and repair. More than 40% of Canadian bridges have crossed half of their anticipated service life. Many of these are structurally deficient and require major maintenance and rehabilitation. Although budget is allocated each year for maintenance and rehabilitation programme, the amount is usually small and covers only 30% to 70% of the actual maintenance needs. This fact raises the need for identifying bridges that require immediate attention where a significant portion of maintenance resources should be utilized. This study developed an integrated bridge prioritization index for a network of bridges to determine the prioritized work considering the importance of the bridge, cost associated with its rehabilitation and current condition. Once the bridge has been selected it is necessary to select proper retrofit techniques. In order to select a suitable retrofit technique this research has compared the performance of a pre-1965 designed multi column bridge bent retrofitted with different rehabilitation techniques, namely FRP jacketing, steel jacketing, concrete jacketing and Engineered Cementitious Composites (ECC) jacketing. The performance of the four different retrofitting strategies is compared in terms of base shear capacity demand ratio, ductility demand, residual drift and damage states obtained from nonlinear Incremental Dynamic Analysis (IDA) and static pushover analysis. Statistical comparisons of static (pushover) against dynamic analyses results have been performed in terms of performance criteria such as displacement and base shear at cracking, yielding and crushing. Moreover, this research assessed the fragility of this retrofitted multi column bridge bent under near fault and far field ground motions. The study aimed to capture the impact of different retrofit techniques on the vulnerability of a retrofitted bridge bent. Through rigorous analyses and applying multi-criteria decision making this study developed a decision making tool that will assist in identifying the most effective retrofitting scheme considering its performance under seismic hazards. The results showed that bridge bent retrofitted with ECC jacketing performed better and deemed to be the optimal retrofit alternative.