Due to the rapid deterioration of reinforced concrete decks (RCD) under the combined effects of deck overloads, weather and salts, the orthotropic steel decks (OSD) that are light weight and require less construction time are being used increasingly to replace old deteriorated decks. In this paper, a numerical investigation was carried out to study the effect of reduction in superstructure weight on the earthquake resistance of elevated girder bridges when an existing RCD was being replaced by an OSD. Firstly, an eigenvalue analysis was carried out to study the effect of superstructure weight on the global vibrational characteristics of the bridge and then, the evaluation of seismic performances of both the bridge models were carried out by performing a series of non-linear dynamic analysis with input earthquake data in the longitudinal and transverse directions separately and simultaneously. The behavior of the pier bases was examined by monitoring the displacement responses and plastic strains during earthquakes. It was found that the bridge model with OSD exhibits a shorter period of vibrations and a huge improvement in the seismic performance of the bridge was observed by replacing the existing RCD with the OSD. The analysis results could be useful in finding a solution for seismic retrofit of existing girder bridges.

中文翻译：

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从RC甲板到正交异性钢甲板的缩颈对高架梁桥抗震性能的影响。

由于钢筋混凝土甲板（RCD）在甲板超载，天气和盐分的共同影响下迅速退化，因此越来越多地使用重量轻且需要较少施工时间的正交异性钢甲板（OSD）来代替旧的退化甲板。本文进行了数值研究，研究了当用OSD代替现有的RCD时，减少上部结构重量对高架梁桥的抗震性能的影响。首先进行特征值分析，以研究上部结构重量对桥梁整体振动特性的影响，然后，通过分别对纵向和横向输入地震数据进行一系列非线性动力分析，对两个桥梁模型的抗震性能进行了评估。通过监测地震期间的位移响应和塑性应变来检查墩基的行为。结果发现，采用OSD的桥梁模型振动周期较短，并且通过将现有的RCD替换为OSD可以观察到桥梁的抗震性能有了很大的提高。分析结果可能有助于找到解决方案，以对现有的梁桥进行地震改造。结果发现，采用OSD的桥梁模型振动周期较短，并且通过将现有的RCD替换为OSD可以观察到桥梁的抗震性能有了很大的提高。分析结果可能有助于找到解决方案，以对现有的梁桥进行地震改造。结果发现，采用OSD的桥梁模型振动周期较短，并且通过将现有的RCD替换为OSD可以观察到桥梁的抗震性能有了很大的提高。分析结果可能有助于找到解决方案，以对现有的梁桥进行地震改造。