摘要
开展了8块再生块体混凝土板的冲切试验,探讨了废旧混凝土块体、配筋率、板厚、板跨等参数对板冲切性能的影响,考察了不同规范预测再生块体混凝土板冲切承载力的有效性,建议给出了相应的修正系数.结果表明:当废旧混凝土强度低于新混凝土时,再生块体混凝土板的初始刚度与常规混凝土板几乎相同,但冲切承载力略有降低;配筋率和冲跨比保持不变时,为提高板的冲切承载力,增大板厚远比减小板跨(即减小柱距)更为有效;在板的冲切承载力计算中,合理考虑配筋的影响是十分必要的,冲跨比较小时现行规范的冲切承载力计算公式有待进一步完善;为使再生块体混凝土板的冲切承载力预测结果具有与常规混凝土板相似的安全性,建议对前者乘以0.95的修正系数.
Punching behavior of eight compound concrete slabs was experimentally studied,and the influences of demolished concrete lumps,reinforcement ratio,thickness of slab and span of slab on the slab’s punching perfor-mance were investigated.Validity of different design codes for predicting the punching shear capacity of the compound concrete slabs was discussed,and a correction coefficient was suggested.It finds that:(a)when the strength of demolished concrete is lower than that of fresh concrete,the initial stiffness of the compound concrete slab is almost the same as that of the conventional concrete slab,but the punching shear strength of the former is slightly smaller than the latter;(b)when the reinforcement ratio and span-to-thickness ratio keep unchanged,increasing the thickness of slab is more effective to enhance the slab’s punching shear strength than reducing the span of slab;(c)it is very necessary to take the steel bars into account during the calculation of the slab’s punching shear strength,when the span-to-thickness ratio is relatively small,the formulae for the punching shear capacity specified in current design codes need to be improved further;and(d)to make the predicted punching shear strength of the compound concrete slab has similar safety margin to conventional concrete slab,a reduction factor of 0.95 is suggested to the former.
作者
吴波
陈宇菲
WU Bo;CHEN Yufei(State Key Laboratory of Subtropical Building Science,South China University of Technology,Guangzhou 510640,Guangdong,China)
出处
《华南理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第8期1-8,共8页
Journal of South China University of Technology(Natural Science Edition)
基金
国家自然科学基金重点项目(51438007)~~
关键词
混凝土板
废旧混凝土块体
冲切试验
冲切承载力
concrete slab
demolished concrete lumps
punching test
punching shear strength
