摘要
为解决正常使用极限状态下体外束应力增量计算方法存在的效率、精度问题,基于试验结果和相关假定将体外束加固连续刚构视为各单跨加固体系,考虑使用荷载作用下体外束曲线变形特征及与梁体相对位置变化的几何关系,通过理论推导得出单跨加固体系在荷载作用下体外束应力增量计算的简析公式。将各单跨加固体系体外束应力增量进行叠加,导出全桥加固体系体外束总应力增量计算公式,并对不同荷载及布束形式下体外束应力增量计算公式进行了探讨。以一座体外束加固连续刚构实桥为算例,运用上述方法对体外束在正常使用极限状态下的应力增量进行了计算,并将计算结果与有限元模型、参考文献结果进行了对比验证。结果表明:体外束加固连续刚构在正常使用初期,体外索的应力增量变化取决于加固体系所承受的荷载,张拉控制应力对其影响不大,而在使用后期,张拉控制应力对体外束应力增量的影响逐渐加大;所提公式对体外束在正常使用极限状态下的应力增量计算具有较高的精度,最大平均误差在5%以内,能够满足工程计算精度的要求,且使结构设计偏于安全;同时,公式形式简单,避免了复杂的有限元建模与能量变分运算,便于工程技术人员掌握,具有较好的实用性。
In order to solve the efficiency and accuracy issues of the calculation method for the stress external prestressing under normal use at limit state,based on experimental results and relevant assumptions,continuous rigid frame reinforced by external prestressing is considered as a single span reinforcement system.Considering the deformation characteristics of the external prestressing curve under load and the geometric relationship with the relative position changes of beam,and through theoretical derivation,a simplified formula for calculating the stress increment of external prestressing of a single span reinforced system under load is derived,and the calculation formula for total stress increment of the external prestressing of entire bridge is derived by superimposing the stress increment of the external prestressing of each single span reinforcement system.The calculation formula for the stress increment of the external prestressing under different loads and beam arrangement forms is discussed.Taking a continuous rigid frame bridge reinforced with external prestressing for an example,the stress increment of external prestressing under normal use at limit state is calculated by using the above method,and the calculation results are compared and verified with FEM and reference results.The result shows that(1)in the early stage of normal use,the stress increment of the external cables in continuous rigid frame reinforced with external tendons depends on the load,the tension control stress has little effect on it,and in the later stage of use,the influence of tension control stress on the increment of external beam stress gradually increases;(2)the proposed formula has high accuracy in calculating the stress increment of the external prestressing under normal use at limit state with a maximum average error of less than 5%,which can meet the requirements of engineering calculation accuracy,and the structural design is biased towards safety;(3)at the same time,the formula with simple form avoids complex finite element modeling and energy variation operations,that is convenient for engineering and technical personnel to master and has good practicality.
作者
高昌
GAO Chang(Shanxi Transportation Planning Survey and Design Institute Co.,Ltd.,Taiyuan,Shanxi 030032,China)
出处
《公路交通科技》
CAS
CSCD
北大核心
2024年第3期111-116,共6页
Journal of Highway and Transportation Research and Development
基金
山西省自然科学基金项目(202203021221025,202203021212306)
山西省高等学校科技创新项目(20212010)。
关键词
桥梁工程
应力增量
理论推导
体外束加固
连续刚构
bridge engineering
stress increment
theoretical derivation
external prestressed reinforcement
continuous rigid frame
