Bulletin of Earthquake Science and Engineering

Bulletin of Earthquake Science and Engineering

Evaluation of the Seismic Behavior of a Concrete Bridge Considering the Influence of the Intermediate Pier Geometry

Document Type : Technical Note

Authors
Behzad Haseli 1
Mohammadreza Mozafarpour taromi 2
1 M.Sc. Graduate, Department of Civil Engineering, Earthquake Engineering, Kharazmi University, Alborz, Iran
2 Ph.D. Candidate, Department of Civil Engineering, Islamic Azad University, South Tehran Branch, Tehran, Iran
10.48303/bese.2024.2031300.1165
Abstract
Bridges are among the most critical components of transportation infrastructure, playing a vital role in a region's economy. Given that bridges are one of the most vulnerable engineering structures, their safety and serviceability are considered to be some of the most challenging issues in the engineering communities of Iran and the world. With population growth and urbanization in recent years, there has been an increase in vehicle usage and traffic volume. Consequently, there is a significant need to construct bridges under various conditions to meet population demands and facilitate vehicle movement and traffic. Therefore, evaluating the seismic behavior of this structure under various parameters leads to a better understanding of its performance and ultimately enables the achievement of an economical, safe, and stable design for this structure. Iran is situated on one of the world's most high-risk zones, and the probability of earthquake-induced damage is extremely high. It is essential to note that bridge construction is not always feasible in a regular configuration. Sometimes, due to executive constraints and the topographic conditions of the target area, the structure must be built asymmetrically. The main objective of the present study was to investigate the influence of the intermediate pier's geometry on the seismic performance of a three-span concrete bridge. After validating and ensuring the accuracy of the modeling procedure in the OpenSees software environment, the first phase of the research identified the most favorable geometric cross-section for the intermediate pier. For this purpose, the three-span concrete bridge was analyzed with three intermediate pier cross-sections: circular, square, and rectangular. Based on the examined responses, the most favorable cross-section was identified. In the second phase of the research, the effect of the irregularity on the seismic performance of the studied bridge was evaluated. In this phase, the heights of the intermediate piers were examined and assessed in three different configurations. In the regular model, the intermediate pier heights were considered equal at 7.13 m. Subsequently, the irregular models of degrees 2 and 3 referred to conditions where the shorter intermediate pier height was considered to be 3.56 m and 2.38 m, respectively. The results of this study indicate that, based on each of the responses—base shear, stress-strain curve, and deck displacement—the most favorable cross-section for modeling the intermediate bridge piers is the circular one. Furthermore, the results show that with an increase in the degree of irregularity, the seismic demand of the bridge increases, and the seismic performance of the bridge in the irregular state decreases compared to the regular state. Specifically, with an increase in the degree of irregularity (from 1 to 3), the base shear, strain, and maximum bridge displacement increased by 10.33%, 54%, and 26.6%, respectively. Thus, the results of this study demonstrate that the most favorable seismic performance of the bridge is related to the regular bridge (with equal pier heights) modeled with intermediate piers having a circular cross-section.
Keywords
Seismic Performance of Bridges
Geometric Irregularity
Intermediate Pier
Cross-Section
Concrete Bridge
OpenSees

Subjects

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  • Receive Date 05 June 2024
  • Revise Date 10 July 2024
  • Accept Date 14 July 2024