The research on strength and distortion of reinforced concrete U-type open section shear walls subjected to bi-directional horizontal force

在建筑结构中，布置u型平面开截面剪力墙的情况也不少。u型开截面剪力墙的结构性能比较复杂，由于其受扭特性的限制，至今没有进行充分的研究。本研究对以下2个系列进行了测试，以获得制作此类墙体数学模型的基础数据。1. 双向横向加载试验限制了u型开截面壁面的扭转。2. 横向扭转载荷试验和纯扭转载荷试验。这些试验的主要结果如下：1. 提出了扭转约束下双向弯曲极限强度预测方法。2. 给出了限制捻度力矩的预测方法。3. 由于扭转的作用，刚性降低，极限强度中的变形增大。4. 圣维南扭矩的影响是不容忽视的。5. St. Venant开裂后扭转刚度降低率为0.28 ~ 0.37。

In building structures, there are not small cases in which open section shear wall with the U-type planar shape is placed. U-type open section shear wall the structural property is complicated, since the twist characteristics is contained, and until now sufficient examination is not carried out. In this study, following 2 series were tested for the purpose of obtaining basic data for making mathematical model of such wall. 1. Bi-directional lateral loading tests restricted the twist of the U-type open section wall. 2. The lateral loading tests with the twist and the pure torsion tests.Main results of these tests are as follows. 1. Bi-directional bending ultimate strength prediction procedure in the twist restraint was proposed. 2. The prediction procedure of the moment for restricting the twist was presented. 3. The rigidity lowers by the twist, and the deformation in the ultimate strength increases. 4. The effect of the torsional moment of St. Venant can not be disregarded. 5. Torsional rigidity lowering rate of St. Venant after the crack was 0.28 〜 0.37.