Effects of bottom bracings on torsional dynamic characteristics of horizontally curved twin I-girder bridges with different curvatures

作     者：Robiul Awall Toshiro Hayashikawa Takashi Matsumoto 

作者机构：Graduate School of Engineering Hokkaido University Faculty of Engineering Hokkaido University 

出 版 物：《Earthquake Engineering and Engineering Vibration》 (地震工程与工程振动（英文刊）)

年 卷 期：2012年第11卷第2期

页      面：149-162页

核心收录：

学科分类：081406[工学-桥梁与隧道工程] 08[工学] 0814[工学-土木工程] 082301[工学-道路与铁道工程] 0823[工学-交通运输工程] 

主　　题：bottom bracing CTIGB FE model torsional stiffness dynamic response negative bearing force 

摘      要：Curved twin I-girder bridges (CTIGBs) have low torsional stiffness that makes them vulnerable to dynamic loads. This study investigates the effects of bottom bracings on the torsional dynamic characteristics of CTIGBs. Five types of bottom bracings are designed to investigate their effects on the dynamic characteristics of CTIGBs with different curvatures under free and forced vibrations. To perform numerical investigations, three-dimensional (3-D) finite element (FE) bridge and vehicle models are established using commercial ANSYS code, and then a vehicle-bridge interaction analysis approach is proposed. Road roughness profiles generated from power spectral density and cross spectral functions are also taken into account in the analyses. The numerical results show that torsional frequencies increase significantly after providing bottom bracings, and the increasing rate depends on the type of bottom bracings and their locations of installation. Bottom bracings can act as load transmitting members from one main girder to the others. Large negative bearing forces that have occurred in bridges with small radii of curvatures can be remarkably reduced by providing bottom bracing systems. It is found that the performances of several bottom bracing systems are effective in improving the torsional dynamic characteristics of the bridges in this study.