钢筋混凝土T形柱在压-弯-剪-扭复合作用下的抗压试验研究

Experimental Study on Compression Behaviour of RC T-shaped Columns under Combined Loads of Compression-bending-shear-torsion

钢筋混凝土构件在复合受力状态下承载力是互相影响的,因此复合受力研究在混凝土结构设计中一直是重要的研究课题。为了研究T形混凝土柱在压-弯-剪-扭复合受力作用下的抗压性能,对12根钢筋混凝土柱平分为4组在复合受力状态下进行了试验研究。以剪力、弯矩和扭矩为变量,讨论了在不同工况下的复合受力对钢筋混凝土柱抗压承载能力、裂缝发展及破坏模式、混凝土和纵向钢筋关键点应变的影响。根据对4组T形钢筋混凝土柱的试验分析,总结了复合受力情况下钢筋混凝土柱抗压承载能力的变化趋势。根据裂缝的破坏过程描述和破坏形态的分析,总结了偏心受压破坏模式向压弯破坏模式转折点和从受压弯破坏到受压弯扭的破坏模式转折点,并且通过比较试验和计算结果,验证了塑性损伤模型的可靠性,同时也说明了试验值的可靠性。在试验数据和已有公式的基础上,扩展了压-弯-剪-扭复合受力情况下的抗压承载能力计算公式和相互作用关系图。得出了在压-弯-剪-扭复合受力情况下不同破坏模式对应的转折点。试验结果表明:抗压承载力随着弯矩、剪力和扭矩的增大而减小。通过试验数据得到T形截面钢筋混凝土柱的抗压承载力公式,能够为复合受力的混凝土抗压承载能力计算提供参考。

The bearing capacity of RC members affects each other in the state of composite stress,so the research of composite stress has always been an important research topic in the design of concrete structures.In order to study the compressive performance of T-shaped RC columns under the combined loads of compression-bending-shear-torsion,12 RC columns are equally divided into 4 groups and tested under the combined stress state.Taking shear,bending moment and torsion as variables,the influences of combined loads on the compressive bearing capacity,crack propagation and failure mode of RC columns,and the strain of key points of concrete and longitudinal reinforcement under different working conditions are discussed.According to the experimental analysis of 4 groups of T-shaped RC columns,the trend of the compressive bearing capacity of RC columns under the combined load is summarized.According to the description of the failure process of the crack and the analysis of the failure mode,the turning point from eccentric compression failure mode to compression bending failure mode and the turning point from compression bending failure to compression bending and torsion are summarized,the reliability of the plastic damage model is verified by the comparison test and calculation result,and the reliability of the test value is also illustrated.On the basis of the test data and the existing formula,the calculation formula of the compressive bearing capacity and the interaction diagram under the condition of the combined loads of compression-bending-shearing-torsion are extended.The corresponding turning points under different failure modes under the combined loads of compression-bending-shear-torsion are obtained.The test result shows that the compressive bearing capacity decreases with the increase of bending moment,shear force and torsion.The formula of the compressive bearing capacity of T-shaped RC column obtained from the test data can provide a reference for the calculation of the compressive bearing capacity of the concrete columns subjected to combined loads.