体外预应力加固变截面连续刚构极限应力计算方法研究  

Method for Ultimate Stress Calculation on Continuous Rigid Frame with Variable Section Reinforced by External Prestressing Force

作　　者：骆佐龙 韩智强 刘陆平 LUO Zuo-long;HAN Zhi-qiang;LIU Lu-ping(School of Electric Power,Civil Engineering and Architecture,Shanxi University,Taiyuan,Shanxi 030000,China;School of Transportation and Logistics,Taiyuan University of Science and Technology,Taiyuan,Shanxi 030000,China;Ji’nan Municipal Engineering Design&Research Institute(Group)Co.,Ltd.,Hefei,Anhui 230000,China)

机构地区：[1]山西大学电力与建筑学院,山西太原030000 [2]太原科技大学交通与物流学院,山西太原030000 [3]济南市市政工程设计研究院(集团)有限责任公司,安徽合肥230000

出　　处：《公路交通科技》2024年第3期117-124,共8页Journal of Highway and Transportation Research and Development

基　　金：中央高校基本科研业务费专项资金资助项目(300102213522);山西省自然科学基金项目(202203021221025);山西省高等学校科技创新项目(2021L010)。

摘　　要：为研究体外预应力加固变截面连续刚构体外束极限应力计算方法,首先,以两座背景工程为例,验证并评价了《规范》公式对于变截面连续刚构加固体系体外束极限应力计算的适用性;其次,在塑性铰个数计算的《规范》公式基础上,引入塑性铰个数修正系数α1以考虑连续刚构结构体系与实际破坏模式下截面转角特征,偏安全地提出加固体系破坏极限状态下塑性铰个数计算的修正公式;然后,通过对中支点失效模型与等效塑性区截面应变分布进行分析,提出中支点截面修正系数α2以考虑中支点截面变化对加固体系体外束有效长度的影响,经理论推导得出α2简析表达式,最终导出变截面连续刚构加固体系体外束极限应力计算修正公式;最后,对已有文献中3个算例进行计算,对比验证修正公式的正确性与适用性。结果表明:应用《规范》公式计算变截面连续刚构加固体系体外束极限应力将产生较大的偏差,且使设计结果偏于不安全,原因在于《规范》公式对变截面连续刚构体外束加固体系在破坏极限状态下塑性铰个数计算偏多及对于连续刚构中支点截面与跨中截面特性的差异考虑不够充分;提出的修正公式对变截面连续刚构体外束加固体系体外束极限应力的计算具有较高的精度与较好的适用性,最大误差在10%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,能够对体外预应力加固变截面连续刚构承载能力极限状态设计提供参考。In order to calculate the ultimate stress in the limit state of bearing capacity for external tendons in continuous rigid frame with variable section reinforced by external prestressing force,firstly,taking 2 background projects for examples,the applicability of the standard formula to ultimate stress calculation of external tendons of continuous rigid frame variable section is verified and evaluated.Secondly,based on the standard formula of plastic hinge number,the correction coefficient of the plastic hinge number represented asα1 is introduced in order to consider the section angle characteristics of continuous rigid frame as well as the actual failure mode,and a modified formula for calculating the plastic hinge number of reinforcement system in limit state is proposed.Subsequently,the section correction coefficient of the middle fulcrum represented asα2 is introduced in order to consider the effect of the section change in middle fulcrum on the effective length of the external tendons,and the analytical expression ofα2 is deduced according to the analysis on the middle fulcrum failure model and the section strain distribution in equivalent plastic zone,and the modified formula for ultimate stress calculating of the reinforced system is derived.Finally,3 numerical examples in existing literature are calculated to verify the correctness and applicability of the modified formula.The result shows that(1)The application of the standard formula to calculate the external tendon ultimate stress of the continuous rigid frame with variable section will produce a large deviation,which makes the structural design unsafe,and the reason is that the plastic hinge numbers of the reinforcement system are to many calculated by the code formula in the limit state and the characteristics for the middle fulcrum section and the middle span section of the continuous rigid frame is considered insufficiently.(2)The proposed modified formula has high accuracy and good applicability for the calculation of external tendon ultimate s

关 键 词：桥梁工程 极限应力 理论分析 体外预应力加固 连续刚构 

分 类 号：U443.3[建筑科学—桥梁与隧道工程]