摘要
通过7个配置HRB500钢筋和3个配置HRB400钢筋Z形试件的推剪试验,得到了新旧混凝土结合面的荷载-滑移曲线和荷载-钢筋应变曲线,分析了结合面处理方法、抗剪钢筋强度及其配筋率对结合面受剪承载力的影响,并对比了按各国规范公式的计算值与试验值。试验研究结果表明:在直剪作用下,试件出现了结合面剪切破坏和试件侧边混凝土冲切破坏两种破坏形态;达到第一峰值荷载时,结合面的滑移量均小于1 mm且抗剪钢筋应变均大于2.0×10-3,而当结合面滑移量达到2.0 mm时,HRB500钢筋均能屈服;键槽面试件的受剪承载力高于粗糙面试件;对结合面剪切破坏的试件,结合面的受剪承载力随结合面配筋率的增大而增大;假定HRB500钢筋屈服,按规程JGJ 1—2014公式计算的受剪承载力均明显小于试验值。利用试验数据,在规程JGJ 1—2014计算公式的基础上,提出了考虑粗糙面有利影响的修正建议。
In order to investigate the performances of the interface between concretes cast at different times under direct shear load,seven Z type specimens with HRB500 steel bars and three with HRB400 steel bars were tested under direct shear load. Relationships between the shear and horizontal slip as well as strain of steel bar were obtained. Test variables including interface characteristics,yield strength and ratio of interface steel bars,and their influences on interface shear capacity were analyzed. The test results were compared with the results of formulas from different standards. It is shown that,under the direct shear load,two kinds of failure patterns are found. One is the interface shear failure,and the other one is the marginal concrete punching failure. At the first peak load,the slip is less than1 mm and the strains of steel bars are more than 2. 0 × 10- 3. The HRB500 steel bars yield at the slip of 2 mm. For the specimens which have the interface shear failure,the larger the ratio of steel bar is,the higher the shear capacity is.The shear capacity of specimens with rough interface is lower than the specimens with shear key. The results of the interface shear capacity calculated based on the JGJ —2014 are obviously lower than the test results assuming the HRB500 steel bars yielded. According to the test results,modification suggestion of the formula in JGJ 1—2014 is presented considering the benefit of rough interface.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2015年第S2期346-353,共8页
Journal of Building Structures
基金
"十二五"国家科技支撑计划(2011BAJ10B02)
关键词
新旧混凝土结合面
HRB500钢筋
直剪试验
受剪承载力
interface between concretes cast at different times
HRB500 steel bar
direct shear test
shear capacity
