پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله فصلنامه علوم و مهندسی زلزله 2476-6097 12 2 2025 06 22 Evaluation of the Seismic Behavior of a Concrete Bridge Considering the Influence of the Intermediate Pier Geometry ارزیابی رفتار لرزه ای پل بتنی با در نظر گرفتن تاثیر هندسه ی پایه میانی 71 83 717486 10.48303/bese.2024.2031300.1165 FA بهزاد حاصلی دانش‌آموخته کارشناسی ارشد، گروه مهندسی عمران، مهندسی زلزله، دانشگاه خوارزمی، کرج، ایران محمدرضا مظفرپور طارمی دانشجوی دکتری، گروه مهندسی عمران، واحد تهران جنوب، دانشگاه آزاد اسلامی، تهران، ایران Journal Article 2024 06 05 <span style="font-size: 11.0pt; line-height: 115%; font-family: 'Calibri','sans-serif'; mso-ascii-theme-font: minor-latin; mso-fareast-font-family: Calibri; mso-fareast-theme-font: minor-latin; mso-hansi-theme-font: minor-latin; mso-bidi-font-family: Arial; mso-bidi-theme-font: minor-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: FA;">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. پل‌ها به‌عنوان یکی از اساسی‌ترین ارکان در سیستم حمل‌ونقل به شمار می‌آیند که نقش مهمی در اقتصاد یک منطقه ایفا می‌کنند. هدف اصلی در پژوهش حاضر، ارزیابی رفتار لرزه‌ای پل بتنی سه‌دهانه، با توجه به هندسه‌ی پایه میانی پل می‌باشد، لذا پس از صحت‌سنجی و اطمینان از روند مدل‌سازی در محیط نرم‌افزار OpenSees، در مرحله‌ی اول پژوهش، مطلوب‌ترین مقطع هندسی پایه‌ی میانی پل شناسایی شده و در مرحله دوم پژوهش، با توجه به این نکته که احداث پل همواره به‌صورت منظم میسر نخواهد بود، تأثیر نامنظمی بر عملکرد لرزه‌ای پل مورد مطالعه، ارزیابی شده است. لذا در این مطالعه، رفتار لرزه‌ای یک نمونه پل سه‌دهانه بتنی در سه حالت مدل‌سازی پایه میانی با مقطع دایره‌ای، مربعی و مستطیلی در محیط نرم‌افزار OpenSees، مورد بررسی قرار گرفته است. نتایج این مطالعه نشان می‌دهد، مطلوب‌ترین عملکرد لرزه‌ای پل مربوط به حالتی است که در آن پایه‌های میانی پل، دارای مقطع دایره‌ای شکل بوده است. سایر نتایج این پژوهش مؤید آن است که ایجاد نامنظمی (ارتفاع نابرابر پایه‌های میانی) اثرات نامطلوبی بر عملکرد لرزه‌ای پل خواهد داشت.

https://www.bese.ir/article_717486_ee9ce5d0a53ac87adc6abcc9427d0b29.pdf