Structural Response and Cost Characterization of Bridge Construction using Seismic Performance Enhancement Strategies
Structural Response and Cost Characterization of Bridge Construction using Seismic Performance Enhancement Strategies
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使用抗震性能增强策略的桥梁施工的结构响应和成本特征
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发表时间：
2009
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通讯作者：
Ady Aviram Traubita
中科院分区：
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作者：
Ady Aviram Traubita
在一项分析和实验研究中，评估了两种创新性能增强技术在加州典型钢筋混凝土桥梁建设中改善的抗震性能和成本效益。所考虑的技术是位于上部结构下方的铅橡胶支座隔震器和用于建造桥墩的纤维增强混凝土。以一座典型的五跨独柱排架钢筋混凝土跨线桥为例，采用这两种方案进行了结构设计，并在OpenSees有限元程序中进行了建模。考虑了两种隔震桥梁的设计方案;一种是柱设计为保持弹性，另一种是在柱中发生轻微屈服（最大位移延性要求为2）。纤维增强混凝土桥柱的分析模型使用两个双向循环试验的结果进行校准，该试验对约1/4比例的圆形悬臂柱样本进行，该样本使用体积分数为1.5%的高强度钩状钢纤维、松弛的横向钢筋和塑性铰区的两种不同纵向钢筋详图的混凝土建造。采用140个地震动对不同的桥梁体系进行了推覆和非线性时程分析。采用PEER基于性能的地震工程方法计算桥梁的震后修复费用和修复时间。脆弱性曲线显示超过特定的维修成本和维修时间阈值的概率。这些桥梁的总成本包括新建筑的成本和地震后的维修成本，这些成本需要75年的结构设计寿命。强度相关的修复时间模型为不同的桥梁计算的船员工作日代表维修工作。进行了财务分析，占范围广泛的贴现率和置信区间的平均每年震后维修成本的估计。尽管初始建设成本略高，但与固定基础常规钢筋混凝土桥梁相比，使用所考虑的两种性能增强技术，特别是隔震技术，获得了可观的经济效益和结构改进。桥梁上部结构的隔离导致了柱和桥台位移和力需求的显着减少。孤立桥梁的修复时间也大大缩短，导致公路系统的连续运行，减少了间接经济损失。实验和分析结果还表明，使用纤维增强混凝土来建造桥梁柱导致改善的损伤容限，剪切强度，和能量耗散下的循环荷载相比，传统的钢筋混凝土柱。这些改进导致更好的抗震性能和更低的75年总成本的纤维增强柱桥。
The improved seismic performance and cost-effectiveness of two innovative performance-enhancement technologies in typical reinforced concrete bridge construction in California were assessed in an analytical and experimental study. The technologies considered were lead rubber bearing isolators located underneath the superstructure and fiber-reinforced concrete for the construction of bridge piers. A typical five-span, single column-bent reinforced concrete overpass bridge was redesigned using the two strategies and modeled in OpenSees finite element program. Two alternative designs of the isolated bridge were considered; one with columns designed to remain elastic and the other such that minor yielding occurs in the columns (maximum displacement ductility demand of 2). The analytical model of the fiber-reinforced concrete bridge columns was calibrated using the results from two bidirectional cyclic tests on approximately ¼-scale circular cantilever column specimens constructed using concrete with a 1.5% volume fraction of high-strength hooked steel fibers, relaxed transverse reinforcement, and two different longitudinal reinforcement details for the plastic hinge zone. Pushover and nonlinear time history analyses using 140 ground motions were carried out for the different bridge systems. The PEER performance-based earthquake engineering methodology was used to compute the post-earthquake repair cost and repair time of the bridges. Fragility curves displaying the probability of exceeding a specific repair cost and repair time thresholds were developed. The total cost of the bridges included the cost of new construction and post-earthquake repair cost required for a 75 year design life of the structures. The intensity-dependent repair time model for the different bridges was computed in terms of crew working days representing repair efforts. A financial analysis was performed that accounted for a wide range of discount rates and confidence intervals in the estimation of the mean annual post-earthquake repair cost. Despite slightly higher initial construction costs, considerable economic benefits and structural improvements were obtained from the use of the two performance-enhancement techniques considered, in comparison to the fixed-base conventionally reinforced concrete bridge, especially seismic isolation. The isolation of the bridge superstructure resulted in a significant reduction in both column and abutment displacement and force demands. The repair time of the isolated bridges was also significantly reduced, leading to continuous operation of the highway systems and reduced indirect economic losses. The experimental and analytical results also demonstrated that the use of fiber-reinforced concrete to build bridge columns leads to improved damage-tolerance, shear strength, and energy dissipation under cyclic loading compared to conventional reinforced concrete columns. These improvements result in better seismic performance and lower total 75-year cost of the fiber-reinforced column bridges.