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Seismic Resilience of Concrete Bridges with Endurance Time Analysis

Ashrafifar, Javid | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53820 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Esmail Pourestekanchi, Homayoon
  7. Abstract:
  8. Highway bridges are one of the key components of transportation network and play a significciant role in the recovery of societies after extreme events such as flood and earthquake. The dysfunction or failure of bridges significantly impacts commerce and services and cause direct and indirect costs. Thus, the recovery of theses components immediately after extreme events is vital issue. In this study, a framework developed to evaluate the life-cycle resilience of bridges using the Endurance Time method. At the first part, the effect of deterioration due to corrosion on the seimic vulnerability and resilience of RC bridge investigated by ET method. To this aim, a procedure described to develop the time-dependent fragility functions with ET and Monte Carlo simulation methods. One of the challenging issues in the evaluation of bridges in the life-cycle context with conventional dynamic time history procedures is the computational efforts of proposed methods, in which the ET method with high accuracy and much less computational demands can solve this problem. Beyond the median estimations via ET method, the dispersion due to record-to-record variability of responses estimated with an indirect methodology. The investigation results indicate the effectiveness and accuracy of ET method with reduced simulation effort for predicting the seismic response probabilistic distribution of highway bridges at different intensities. After fragility analysis, the direct and indirect losses of bridge system in the life-cycle context obtained. Also, different appropriate recovery functions employed based on the damage level of structure. Finally, the resilience indext in the bridge servise years computed. A degrading nonlilear trend observed at bridge resilience as it aged. At high seismic intensities, the aging has more impact on the seismic resilience than low intensities. The results depicted the importance of life-cycle seismic resilience evaluation of the highway bridges. At the second part, the effects of aging due to the scour of piers on the seismic vulnerability and seismic resilience of bridges investigated with the proposed framework. The 3D finite elemet models of bridges at pristine and eight different scour depths generated. The Endurance Time analysis performed to develop the fragility and loss curves of scoured-bridges. Then the resilience index computed for scoured bridges. The results showed that the resilience of bridges decreases with both scour depths and seismic intensity; however, it does not decrease linearly with scour depths and seismic intensity. It should be noted that the scour doesn’t have signifficiant effects at low seismic intensities, and it raises by increasing intensities. Finally, the effects of pounding between adjacent components (Deck-end and Abutment) and skewness degree on the vulnerability of bridges predicted via ET method. FE models by considering and not considering pounding effects with different skewness degrees generated and subjected to ET seismic loads. Furthermore, the effectiveness of ET method for analyzing the pounding responses of skewed highway bridges investigated. The results showed that considering pounding effects in skewed bridges is more crucial than straight bridges
  9. Keywords:
  10. Endurance Time Method ; Aging ; Seismic Resilience ; Damage ; Scour ; Seismic Damage ; Highway Bridges

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