往复荷载下自复位CFST桥墩预应力工作及损失机理试验  

Experimental Study on Prestressed Working and Loss Mechanism of Self-centering CFST Bridge Columns Under Cyclic Load

作　　者：贾俊峰[1] 刘洋 邱灿星 郭河 赵建瑜 郭彬立 张凯迪 JIA Jun-feng;LIU Yang;QIU Can-xing;GUO He;ZHAO Jian-yu;GUO Bin-li;ZHANG Kai-di(Key Laboratory of Urban Security and Disaster Engineering,Ministry of Education,Beijing University of Technology,Beijing 100124,China;CCCC Infrastructure Maintenance Group Co.Ltd.,Beijing 100102,China;The China ENFI Engineering Co.Ltd.,Beijing 100080,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124 [2]中交基础设施养护集团有限公司,北京100102 [3]中国恩菲工程技术有限公司,北京100080

出　　处：《中国公路学报》2024年第4期176-187,共12页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52178449)。

摘　　要：为研究预应力筋参数对自复位预制节段桥墩抗震性能的影响,进一步推动自复位预制拼装桥墩体系在强地震区的发展,设计了5个自复位预制节段钢管混凝土(Concrete Filled Steel Tube, CFST)桥墩试件,以考虑不同的预应力筋面积、初始张拉力及预应力损失的影响,并开展了拟静力往复荷载试验。基于试验数据,分析了桥墩损伤模式、预应力损失及锚具回缩、滞回曲线、骨架曲线、耗能能力和受压区高度等地震行为。研究结果表明:设计的自复位预制节段CFST桥墩表现出良好的抗震性能及自复位能力,最大水平位移荷载下残余偏移率仅为0.41%,同时未出现明显损伤现象;水平往复荷载作用下,桥墩预应力损失值在12%~25%,其中锚具回缩造成的预应力损失占比最大为70.3%,且锚具回缩值在加载位移大于历史位移时增加,建议对预应力筋采用一定超张拉以减小锚具回缩带来的损失;桥墩侧向承载力与预应力初始张拉力呈明显正相关,预应力筋面积的增加会增大屈服后刚度,建议预应力筋最低配筋率不小于0.8%;预应力筋初始张拉力及面积的改变并不会影响桥墩受压区高度,其在加载后期基本趋于定值。研究结果可为自复位预制节段CFST桥墩的结构设计和优化提供参考。To explore the influence of post-tensioned(PT) tendon parameters on the seismic performance of self-centering precast bridge columns and further promote the development of a self-centering precast bridge column system in moderate and high seismic regions, five self-centering precast segmental concrete-filled steel tube(CFST) bridge columns were designed in this study considering different areas, initial PT forces, and stress losses of the PT tendons. In addition, quasi-static cyclic loading tests were conducted. Based on the experimental results, seismic behaviors such as the damage model, PT stress losses, retraction of the anchorage of the bridge columns, hysteretic curves, skeleton curves, energy-dissipative capacity, and height of the compression zone were analyzed. The research results show that the designed precast segmental CFST bridge columns exhibit satisfactory seismic performance and self-centering ability;the residual drift ratio is only 0.41%, and no apparent damage phenomenon was observed under the maximum horizontal displacement load. Under the cyclic horizontal load, the value of the PT stress losses of the bridge columns is 12%-25%, the ratio of PT stress losses caused by the retraction of the anchorage is 70.3%, and the amplitude of the retraction of the anchorage increases as the loading displacement exceeds the historical displacement. Thus, the PT tendon should be over-tensioned to reduce the PT stress losses due to the retraction of the anchorage. The horizontal bearing capacity of the bridge columns significantly positively relates to the initial PT force, and an increase in the area of the PT tendon will enhance the post-yielding stiffness. This indicates that the minimum reinforcement ratio should not be less than 0.8%. Moreover, the initial PT force and area of the PT tendon does not affect the height of the compression zone, and the value tends to remain constant in the later stage of loading. The research results will provide a reference for the structural design and optimization of se

关 键 词：桥梁工程 钢管混凝土桥墩 拟静力试验 自复位 抗震性能 预应力筋参数 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]