重复荷载作用后海工高性能混凝土梁刚度退化试验研究  

Experimental analysis of bending stiffness degradation of marine high-performance concrete beam after action of repeated loads

作　　者：陆春华[1] 吴小龙 蔡启明 张菊连 LU Chunhua;WU Xiaolong;CAI Qiming;ZHANG Julian(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,Jiangsu,P.R.China;Shanghai Horizon Construction Technology Co.,Ltd.,Shanghai 201800,P.R.China)

机构地区：[1]江苏大学土木工程与力学学院,江苏镇江212013 [2]上海宏信建筑科技有限公司,上海201800

出　　处：《土木与环境工程学报（中英文）》2024年第3期171-179,共9页Journal of Civil and Environmental Engineering

基　　金：国家自然科学基金(51878319)。

摘　　要：在荷载长期作用下,钢筋混凝土受弯构件的变形是一个重要的评价指标,也是构件正常使用极限状态的验算内容之一。为了研究经历重复荷载后海工高性能混凝土梁的变形发展规律,设计制作了10根试验梁,分别进行了重复荷载试验、氯盐干湿试验以及两者的共同作用试验;通过四点受弯试验对梁的跨中挠度及刚度退化进行评价,提出了梁短期刚度规范计算公式的修正方法。研究结果表明:荷载水平按梁纯弯段弯矩等于0.4M_(u)确定时,施加30次重复荷载后混凝土的损伤度接近15%;对于仅进行氯盐干湿循环的试验梁,其跨中挠度发展要慢于参照梁;施加重复荷载后,试验梁的跨中挠度发展要快于参照梁;对施加重复荷载后的试验梁再进行氯盐干湿循环,梁的刚度退化更为显著。结合试验结果,采用损伤效应折减系数对梁短期刚度计算公式进行修正,并验证了修正公式的合理性和有效性。Under long-term loading,the deformation of reinforced concrete flexural members is an important evaluation index and it is one of the checking contents of the serviceability limit state.To study the degradation law of bending stiffness of marine high-performance concrete beams after action of repeated loads,a total of 10 test beams were designed and fabricated.After exposure to the repeated load test,the chloride solution dry-wet cycle test and their coupled test,the mid-span deflection development and stiffness degradation of the test beams were evaluated using the four-point bending test.A modified method for the code formula of beam shortterm stiffness is proposed.The test results indicate that when the load level is determined according to the moment of the beam’s pure bending section equal to 0.4M_(u),the damage degree in concrete approaches 15% after 30 cycles of repeated load.For the test beams exposed only to the chloride solution dry-wet cycles,their mid-span deflection develops slower than that of the reference beam.After the action of repeated loads,the midspan deflection of these test beams develops faster than that of the reference beam.When the damaged beams were exposed to chloride solution dry-wet cycles,their degradation of bending stiffness became more obvious.Based on the experimental results,the damage effect reduction factors were proposed to revise the calculation formula of beam,s short-term stiffness.The rationality and effectiveness of the revised formula are verified by the test data.

关 键 词：重复荷载 海工混凝土梁 损伤度 氯盐环境 弯曲刚度 

分 类 号：TU375.1[建筑科学—结构工程]