（1 中设设计集团股份有限公司， 南京 210000；2东南大学土木工程学院， 南京 210096；3 湘潭大学土木工程与力学学院， 湘潭 411100; 4 江苏东部高速公路管理有限公司， 盐城 224002）

［摘要］通过对1根未加固对比梁和3根加固梁进行正截面四点弯试验研究，探讨了二次受力对聚乙烯醇纤维增强钢丝网水泥基复合材料（PVA-RFCC）加固RC梁弯曲性能的影响。结果表明：PVA-RFCC是一种有效的加固材料，与加固对比梁相比，二次受力对PVA-RFCC加固RC梁的极限承载力和刚度系数（屈服阶段）影响比较小，但开裂荷载和刚度系数（弹性阶段）均降低约30%。二次受力对试验梁的抗弯性能影响与试验梁在加固之前的损伤程度有关；当损伤程度分别为加固对比梁的27.6%，82.8%时，位移延性系数分别增加54.1%和降低26.6%。因此，当梁处于初始损伤状态时对其进行加固，可以提高梁的综合力学性能。

［关键词］二次受力； PVA-RFCC； 抗弯性能； 刚度系数； 位移延性系数； 损伤程度

中图分类号：TU375文献标识码：A文章编号：1002-848X(2020)15-0015-05

Experimental study on flexural behavior of RC beams strengthened with PVA-RFCC under secondary load

YUAN Weiwei1, DU Wenping2, YANG Caiqian2,3, WANG Chong2, ZHU Fawang2, PAN Yong4, MENG Chunlin4

(1 China Design Group Co., Ltd., Nanjing 210000, China; 2 School of Civil Engineering, Southeast University, Nanjing 210096, China; 3 College of Civil Engineering and Mechanics, Xiangtan University, Xiangtan 411100, China; 4 Jiangsu Eastern Expressway Management Co., Ltd.， Yancheng 224002, China)

Abstract:A four-point bending experimental of one unstrengthened control beam for comparison  and three strengthened beams were investigated. The influence of secondary load on the flexural behavior of RC beams strengthened with polyvinyl alcohol fiber reinforced ferrocement cementitious composite (PVA-RFCC) was discussed. The results shows that PVA-RFCC is the most excellent strengthening materials. Compared with strengthened control beam, the secondary load of RC beams  strengthed with PVA-RFCC has little influence on load carrying capacity and stiffness coefficient in the yielding stage. But the cracking load and stiffness coefficient in the elastic stage of strengthened beams all decreased about 30% under secondary load. The influence of secondary load on the flexural behavior is related to the damage degree of beams before reinforcement. When the damage degrees of the strengthened beam are 27.6% and 82.8%, the displacement ductility coefficient increased by 54.1% and decreased by 26.6% respectively. Therefore, the beams should be strengthened when they are in initial damage state, which can improve the comprehensive mechanical properties.

Keywords:secondary load; PVA-RFCC; flexural behavior; stiffness coefficient; displacement ductility coefficient; damage degree

*湖南省重点研发计划（2018WK2111），湖南省创投项目（2018GK5028）。

作者简介：袁微微，硕士，高级工程师，Email:38836669@qq.com；通讯作者：杨才千，博士，教授，Email:ycqjxx@seu.edu.cn。