Shear in Reinforced Concrete

剪力作用是钢筋混凝土结构破坏的一个重要因素。发展了一种软化桁架模型理论，该理论能够预测各种类型结构在剪切为主时的行为。第一个目标是推广软化桁架模型理论，以便将其应用于剪切(扭转)和轴向荷载相结合的情况。第二个目标是对40块全尺寸钢筋混凝土板进行试验，以确定一般理论所要求的材料规律，包括软化规律、裂缝的本构规律和混凝土的贡献规律。这项研究将在休斯顿大学最近完成的耗资44万美元的专门测试设备中进行。该设施由一个巨大的钢框架组成，其中嵌入了40个千斤顶，每个千斤顶的容量为100吨，可以测试55平方英寸厚的钢筋混凝土面板，厚度可达16英寸。一般桁架模型理论的建立与有限元方法的结合，将使人们能够预测整个范围的结构在薄膜应力作用下的行为(墙和壳)。

Shear action is an important factor in the failure of reinforced concrete structures. A softened truss model theory has been developed that is capable of predicting the behavior of various types of structures when shear is predominant. The first objective is to generalize the softened truss model theory so that it can be applied to situations where shear (torsion) is combined with axial loads. The second objective is to perform tests on 40 full.size reinforced concrete panels in order to determine the material laws required in the general theory, including the softening law, the constitutive law of cracks, and the law governing the contribution of concrete. The research will be carried out in a $440,000 panel.testing facility recently completed at the University of Houston. This facility consists of a giant steel frame embedded with 40 jacks of 100.ton capacity each, which can test reinforced concrete panels 55 inches square and up to 16 inches thick. Establishment of a general truss model theory in conjunction with the finite element method will permit one to predict the behavior of a whole range of structures subjected to membrane stresses (walls and shells).