论文部分内容阅读
钢管混凝土短柱在地震中易遭受脆性剪切破坏。为评估圆形或方形钢管短柱的性能,对轴向恒载和侧向往复荷载组合作用下的8个短柱构件进行了测试。测试的构件包括3个圆形钢管柱和3个方形钢管柱,另外2个为普通钢筋混凝土短柱(其中一个为圆形柱,另一个为方柱)。试验结果表明:普通钢筋混凝土短柱在遭受脆性剪切破坏时延性很差,但由于外层薄钢管对核心混凝土的包裹作用,使得钢管混凝土短柱的延性明显增强。圆形钢管混凝土短柱的侧向承载强度随着轴向加载率的增大而增大,但轴向加载率对其塑性变形能力的作用不大。对于方形钢管混凝土短柱,抗剪强度会随着轴向加载率的增大而增大,但塑性变形能力会随着轴向加载率的增加而减小。钢管混凝土短柱中,圆形钢管比方形钢管能更有效地防止核心混凝土发生剪切破坏。基于试验和分析结果,采用了改进的ACI设计方法来计算方形和圆形钢管柱的名义抗剪强度。
Concrete filled steel tubular short columns are vulnerable to brittle shear failure in the earthquake. In order to evaluate the performance of circular or square steel tubular stubs, eight short-column members under combined axial and lateral reciprocating loads were tested. The test components consisted of 3 circular steel columns and 3 square steel columns, the other 2 were ordinary reinforced concrete short columns (one was a circular column and the other was a square column). The experimental results show that the ductility of ordinary reinforced concrete short columns subjected to brittle shear failure is poor, but the ductility of the concrete-filled steel tubular short columns is obviously enhanced due to the wrapping effect of the outer thin-walled steel tube on the core concrete. The lateral bearing strength of circular CFST columns increases with the increase of axial load, but the effect of axial load on the plastic deformation ability is insignificant. For square concrete-filled CFST columns, the shear strength increases with the increase of axial load, but the plastic deformation capacity decreases with the increase of axial load. In concrete-filled steel tubular short columns, circular tubes are more effective than square tubes in preventing shear failure of core concrete. Based on the experimental and analytical results, a modified ACI design methodology was used to calculate the nominal shear strength of square and round steel columns.