钢筋混凝土板柱节点抗冲切试验研究

Experimental investigation of punching shear failure of reinforced concrete slab-column connections

完成了9个冲跨比为7的钢筋混凝土板柱节点受冲切破坏试验,得到了荷载-挠度曲线、应变及破坏形态等信息。根据本试验结果和历史试验数据,分析了混凝土强度、纵向配筋率、纵筋屈服强度等因素对试验板破坏形态及受冲切承载力的影响,并将受冲切承载力试验值与我国混凝土规范GB 50010—2010、美国规范ACI 318-08、欧洲规范EN 1992-1-1∶2004和CEB-FIP Model Code 2010规范的计算值进行了对比。结果表明:相对于普通强度混凝土板柱节点,高强混凝土板柱节点的破坏特征对配筋情况并不敏感;混凝土强度和配筋率的变化将影响构件的破坏模式;我国混凝土规范计算得到的高强混凝土板柱节点受冲切承载力比普通强度混凝土板柱节点的计算结果保守;我国混凝土规范中的混凝土抗拉强度不能很好地反映混凝土强度对受冲切承载力的影响;纵筋配筋率对受冲切承载力有较大影响。

A total of 9 reinforced concrete slab-column connections with punching-span ratio equal to 7 were tested,key information such as the load-deflection curves,strains and failure modes were obtained. Based on the test results and previous data,the effects of concrete strength,ratio and yield strength of longitudinal reinforcement on the failure modes and punching shear capacity were analyzed. Then,the experimental punching shear capacity of all slabs were compared with the calculating values of Chinese concrete code GB 50010—2010,American code ACI 318-08,Euro code EN 1992-1-1∶ 2004 and CEB-FIP Model Code 2010. The results indicate that failure characteristics of high strength concrete slabcolumn connections are not sensitive to the reinforcement ratio,when compared to specimens with normal strength concrete.The failure modes are affected by concrete strength and reinforcement ratio. The calculated punching shear capacity of high strength concrete slab-column connections based on the Chinese concrete code are more conservative than that of specimens with normal strength concrete. The tensile strength of concrete in Chinese concrete code can＇t abundantly reflect the effect of concrete strength on punching shear capacity and the longitudinal reinforcement ratio shows great influence on the punching shear capacity.