考虑徐变恢复的变荷载下PC梁徐变效应精细化分析  

Refinement Analysis of PC Beam Creep Effect Under Variable Load Considering Creep Recovery

作　　者：赵煜[1] 王志伟 药天运 周勇军[1] 景媛 高权 ZHAO Yu;WANG Zhi-wei;YAO Tian-yun;ZHOU Yong-jun;JING Yuan;GAO Quan(School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China;School of Civil Engineering,Chang'an University,Xi'an 710061,Shaanxi,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]长安大学建筑工程学院,陕西西安710061

出　　处：《中国公路学报》2023年第10期345-356,共12页China Journal of Highway and Transport

基　　金：国家重点研发计划项目(2021YFB1600302);中央高校基本科研业务费专项资金项目(300102282108);国家自然科学基金项目(51908049)。

摘　　要：为探究考虑徐变恢复的变荷载作用下预应力混凝土结构徐变规律,对5种工况下的15片模型梁进行119 d的长期试验,分析室温环境变荷载作用下预应力混凝土梁徐变应变及受力应变发展规律。结合逐步计算法及预应力混凝土徐变恢复模型,建立了考虑徐变恢复的变荷载下徐变计算方法,并进一步利用ABAQUS软件的二次开发平台建立考虑混凝土徐变恢复的徐变本构UMAT子程序,以实现对全试验周期变荷载下预应力混凝土梁徐变过程的仿真分析。研究结果表明:混凝土龄期达到119 d时,递减荷载组、递增荷载组及波动荷载组的徐变应变依次增大,且均明显小于恒荷载组的结果;递增荷载组、递减荷载组及波动荷载组徐变仿真结果与试验测试数据的最大误差分别为12%、9%及4%,3种工况受力应变仿真结果与试验测试数据的最大误差分别为10%、5%及8%,因此所建立的理论及仿真模型可以对变荷载下的徐变物理现象进行精细化分析;徐变恢复在总徐变中占比明显不能忽略,对于递减荷载组,不同龄期下徐变恢复应变为徐变应变的5%~11%,对于波动荷载组,该值增加至11%~18%;中国《公路钢筋混凝土及预应力混凝土桥涵设计规范》(JTG 2018-336504)中徐变应变计算结果明显大于试验测试数据,是较为保守的结果;所建立的徐变精细化分析方法可以为处于变荷载作用下的大跨径预应力混凝土连续刚构桥长期徐变效应分析提供技术支撑。To explore the creep law of prestressed concrete structures under variable load considering creep recovery,a 119-day long-term test of 15 model beams under five loading conditions was carried out.The development law of the creep and stress strains of the prestressed concrete beams under variable load at room temperature was analyzed.Combining a step-by-step calculation method and the prestressed concrete creep recovery model,a creep calculation method under variable load considering creep recovery was established.In addition,the further development platform of ABAQUS software was used to establish the creep constitutive UMAT subroutine considering the creep recovery of concrete.Finally,a simulation analysis of the creep process of prestressed concrete beams under variable loads during the whole test cycle was realized.The research results show that when the age of concrete reaches 119 days,the creep strains for the load groups increase in the following order:decreasing,increasing,and fluctuating loads.Meanwhile,they are all significantly smaller than the results for the constant load group.The maximum errors between the creep simulation results and test data of the increasing,decreasing,and fluctuating load groups are 12%,9%,and 4%,respectively.The maximum errors between the stress strain simulation results and test data of those three working conditions are 10%,5%,and 8%,respectively.Therefore,the theoretical and simulation methods considering creep recovery used in this study can analyze the physical phenomenon of creep under variable loads accurately.Additionally,the creep recovery strain at different ages is 5%-11%of the creep strain for the decreasing load group and the values increase to 11%-18%for the fluctuating load group.Therefore,the proportion of creep recovery in the total creep cannot be ignored.The analysis results of this study show that the calculation results of creep strain in the Specifications for Design of Highway Reinforced Concrete and Prestressed Concrete Bridges and Culverts(JTG 2018-336

关 键 词：桥梁工程 预应力混凝土梁 徐变恢复 变化荷载 UMAT子程序 

分 类 号：U448.35[建筑科学—桥梁与隧道工程]