钢筋混凝土异形柱-板连接冲切特性试验研究

针对柱截面形式为异形柱的板柱冲切试验很少以及我国规范未对此明确规定的情况,本文进行了9个柱截面为3种典型异形柱(十字形、T形和L形)-板连接和2个方柱-板连接在未配置抗冲切钢筋时的冲切特性对比试验。阐述了异形柱-板连接的冲切受力性能和破坏特征,并将其受冲切特性与相应的等面积方柱和等有效周长方柱板柱连接试件进行了对比,讨论了异形柱和方柱板柱连接冲切特征的差异。试验结果表明,与相应的方柱-板连接试件相比,异形柱-板连接试件具有较高的抗冲切承载力及延性。根据试验结果提出了符合我国设计实践的异形柱板柱冲切承载力计算方法。并用国外几个主要规范以及我国规范所推荐的冲切承载力计算公式对上述试验板的受冲切承载力进行了验算,相对而言,抗弯钢筋配筋率较高时,我国规范及ACI规范的预测值与试验值相比偏于保守。本文试验结果可供规范修订时参考。

Experimental investigation on punching shear behavior of concrete slab nonrectangular column connections

An experimental program was carried out to investigate the punching shear behavior of RC slab nonrectangular column connections. Nine specimens with typical specially shaped columns (cross shaped section, T shaped section and L shaped section) and two reference specimens with square columns were tested under central loads. The tested ultimate loads, deformations and failure modes of specimens are presented in the paper. Test results revealed that the punching shear strength and ductility of the connections with nonrectangular columns were higher than that of the corresponding connections with square columns. Based on the test results, a method for calculating punching shear strength of connections with speacially shaped columns is proposed, which conforms with the current design practice of China. The test results on the punching shear strength were compared with the predictions of the formulas proposed by codes of practice ACI 318—95, BS 8110, CEB FIP Model Code and GB 50010—2002, it was found that ACI code and China code gave conservative predictions as the reinforcement ratio was increased.