The end diaphragm of bridges are normally designed to resist lateral seismic forces imposed on the superstructure in earthquake prone regions. Using ductile diaphragms with high deformation capacity could reduce the seismic demands on the substructure and prevent costly damage under strong ground motions. The end diaphragms of steel tub girder bridges with high lateral stiffness and dominant shear behavior have a potential to be used as ductile fuse elements. In this study, a steel plate shear diaphragm (SPSD) is introduced as an external end diaphragm of tub girder steel bridges to reduce the seismic demands imposed on the substructure. Quasi static nonlinear analyses were conducted to evaluate responses of sixteen SPSDs with different boundary conditions, aspect ratios and diaphragm plate thicknesses. Moreover, nonlinear time history analyses were performed using three different ground motions corresponding to DBE and MCE level spectrums. Cyclic and time history analyses proved the proper behavior of SPSD and its efficiency to reduce seismic demands by more than 25%.

中文翻译：

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球墨铸铁板外端隔板，用于钢制大梁直的公路桥梁

桥梁的端部膜片通常设计为在地震多发地区抵抗施加在上部结构上的横向地震力。使用具有高变形能力的延性膜片可以减少对下部结构的抗震要求，并防止在强地面运动下代价高昂的破坏。具有高侧向刚度和主要剪切特性的钢制箱梁桥的端部膜片有潜力用作延性的熔断元件。在这项研究中，钢板剪力膜片（SPSD）被引入到桶形梁钢桥的外端膜片中，以减少对下部结构施加的地震要求。进行了准静态非线性分析，以评估具有不同边界条件，纵横比和隔板厚度的16个SPSD的响应。此外，使用对应于DBE和MCE水平谱的三种不同的地面运动进行了非线性时程分析。循环和时程分析证明了SPSD的正确行为及其将地震需求减少25％以上的效率。