氯盐与重复荷载共同作用下海工混凝土梁受弯性能退化分析  

Degradation analysis of flexural performance of marine concrete beams under combined action of chloride and repeated load

作　　者：陆春华[1] 宋泽鹏 李锺奥 张菊连 LU Chunhua;SONG Zepeng;LI Zhongao;ZHANG Julian(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,Jiangsu,China;Shanghai Horizon Construction Technology Co.Ltd.,Shanghai 201800,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：《建筑科学与工程学报》2023年第5期52-59,共8页Journal of Architecture and Civil Engineering

基　　金：国家自然科学基金项目(51878319)。

摘　　要：为研究氯盐与重复荷载共同作用下海工混凝土梁受弯性能的退化规律,选用硅灰、粉煤灰、纳米二氧化硅制备了3组共10根海工混凝土梁。通过两两自锚和在梁受拉侧设置吸水海绵的方式,实现了对试验梁施加重复荷载的同时进行氯盐干湿循环作用,经30次循环后对试验梁的受弯性能进行了评价。结合试验结果,提出了重复荷载作用下海工混凝土梁受弯承载力退化系数,并给出了海工混凝土梁受弯承载力退化计算公式。结果表明:对于仅进行氯盐干湿循环的梁,其荷载-挠度曲线发展与对比梁类似,且极限弯矩略有提高;对于氯盐和重复荷载共同作用下的梁,随着重复荷载水平的增大,梁的受弯裂缝开展及破坏形态未发生明显的变化,但其极限弯矩却出现了明显退化,同时梁的变形能力及其延性性能均呈现大幅下降;相同条件下,复掺粉煤灰和硅灰的海工混凝土梁受弯性能更优,且在氯盐与重复荷载共同作用下的受弯性能退化程度较低;通过试验实测结果与公式预测结果对比分析,验证了受弯承载力退化公式的合理性和有效性。To investigate the degradation law of flexural performance of marine concrete beams under the combined action of chloride and repeated load,silica fume,fly ash and nano-silica were selected to prepare 3 groups of 10 marine concrete beams.By means of self-anchoring in pairs and setting water absorbent sponge at the tension zone of test beams,the repeated loads were applied to the test beams together with the dry-wet cycles of chloride solution.The flexural performance of the test beam was evaluated after 30 cycles.Combined with the test results,the influence coefficientα(λ)of repeated load levelλon the degradation of flexural capacity of marine concrete beams was proposed,and the calculation formula of the degradation of flexural capacity of marine concrete beams was given.The results show that the load-deflection curve of the beam only subjected to chloride dry-wet cycle is similar to that of the contrast beam,and the ultimate bending moment is slightly increased.For the beam under the combined action of chloride and repeated load,with the increase of repeated load level,the development of flexural crack and the failure mode does not change significantly,but the ultimate bending moment shows obvious degradation,and the deformation capacity and ductility of the test beam decrease significantly.Under the same condition,the flexural performance of marine concrete beams mixed with fly ash and silica fume is better,and the degradation degree of flexural performance under the combined action of chloride and repeated load is lower.The rationality and validity of the bending capacity degradation formula are verified by comparing the experimental results with the formula prediction results.

关 键 词：海工混凝土梁 氯盐环境 重复荷载 受弯性能 

分 类 号：TU375.1[建筑科学—结构工程]