摘要
为探究地震等偶然往复荷载作用下摇摆自复位(Rocking self-centering,RSC)结构夹片式锚具回缩引起的预应力损失规律及其计算方法,提出了锚具回缩理论模型,设计并开展了不同预应力筋数量及长度与不同加载制度下预应力损失试验研究。基于试验结果,分析了RSC柱瞬时预应力损失与偶然预应力损失变化规律,并编写了新型锚具材料UMAT子程序。研究结果表明:锚具回缩为永久变形,且仅随历史最大预应力值线性增加,锚固端锚具回缩相较于张拉端锚具回缩存在一定滞后效应。不同预应力筋参数及加载制度下,各锚具的“预应力增量-锚具回缩”斜率基本保持不变,变异系数仅为0.079,表明锚具回缩具有良好的可预测性。偶然预应力损失超过初始有效预应力将导致预应力筋发生完全松弛,在实际设计中需合理评估预应力损失与初始预应力间的平衡关系,确保初始有效预应力大于偶然预应力损失,以避免预应力筋松弛现象的产生。所提出的锚具回缩理论模型与新型锚具材料UMAT子程序能够准确模拟地震等偶然荷载作用下锚具回缩变化规律。研究成果可为RSC结构预应力筋设计优化及预应力损失分析提供参考。
To investigate the pre-stress loss variation and the corresponding calculation method induced by the retraction of wedge-type anchorage in rocking self-centering(RSC)structures subjected to accidental reciprocating loads such as earthquakes,a theoretical model for anchor retraction was developed.Experimental studies were designed and conducted to examine pre-stress loss under various conditions,including different numbers and lengths of prestressed tendons,as well as diverse loading protocols.Based on the experimental results,the variation trends in instantaneous and accidental pre-stress losses of RSC structures were analyzed,and the UMAT subroutine for an innovative anchor material was developed.The research results indicate that the anchor retraction is a permanent deformation and only increases linearly with the historical maximum prestress force.There is a noticeable lag effect in anchor retraction at the anchorage end compared to the tension end.Under different prestressing parameters and loading protocols,the slope of“force increment-anchorage retraction”for each anchor remains relatively constant,with a coefficient of variation of only 0.079,indicating a high level of predictability for anchor retraction.Accidental pre-stress loss exceeding the initial effective stress will result in complete relaxation of the prestressed tendons.In practical design,it is necessary to reasonably evaluate the balance between pre-stress loss and initial stress,which ensures that the initial effective pre-stress force is greater than the incidental pre-stress loss to avoid relaxation of prestressed tendons.The proposed theoretical model of anchor retraction and the UMAT subroutine of anchor material can accurately simulate the variation trends in anchor retraction under accidental loads such as earthquakes.The research results can provide reference for the optimization of prestressed tendons design and analysis of pre-stress loss in RSC structures.
作者
贾俊峰
刘洋
赵建瑜
周智
邓贺丹
江昊
JIA Jun-feng;LIU Yang;ZHAO Jian-yu;ZHOU Zhi;DENG He-dan;JIANG-Hao(State Key Laboratory of Bridge Safety and Resilience,Beijing University of Technology,Beijing 100124,China;China Highway Engineering Consulting Group Co.Ltd.,Beijing 100089,China;School of Civil Engineering and Architecture,Hainan University,Haikou 570228,Hainan,China;China ENFI Engineering Co.Ltd.,Beijing 100038,China)
出处
《中国公路学报》
北大核心
2026年第2期98-107,共10页
China Journal of Highway and Transport
基金
国家国际科技合作专项(2024YFE0198400)
国家自然科学基金项目(52478485)
北京市自然科学基金项目(8234060)。
关键词
桥梁工程
摇摆自复位结构
理论模型
夹片式锚具
预应力损失
锚具回缩
bridge engineering
rocking self-centering structure
theoretical model
wedge-type anchorage
pre-stress loss
anchor retraction
