Research on Aseismic Behaviors of Reinforced Concrete Columns with Wallgirders Subjected by Two-directional Lateral Forces

同向带墙梁的钢筋混凝土柱在该方向和横向的剪跨比不同。由此推测，在水平荷载作用下，各个方向的屈服铰出现在不同的部位，两个方向的破坏模式也可能不同。方形截面30 cm×30 cm的柱状试件，一个方向有墙梁，另一个方向有梁，在三种墙梁高度、两种柱子横向配筋率和两种横向加载方案的组合下，由六个变量组成。单向加载是指在墙梁方向和梁方向上交替进行反向加载。双向加载是指柱的顶端沿椭圆轨道移动而产生的循环荷载，由于墙梁的深度越大，柱的可变形长度越短，由于屈服铰区所需的弯矩较大，试验柱在抗弯强度下的剪力比计算值大。因此，按顺序抗剪强度设计要求配剪配筋的柱在墙梁方向上发生剪切破坏。然而，这种高抗剪配筋的柱具有抗弯强度和变形能力。轴心柱筋沿墙梁方向的曲率或应变最大值出现在柱中开口部分的略外侧，梁方向的最大值出现在柱端。双向加载下的极限抗弯强度和延性均小于单向加载下的极限抗弯强度和延性，但滞回环的能量吸收较大。

Reinforced concrete columns with wallgirders in one direction have different shear-span ratios between in this direction and in transverse direction. Therefore it is conjected that yield hinges occured under lateral forces in the each direction appear at different portions from each other and also it may well be that failure modes are different between both directions.Column specimens with a square section of 30cm by 30cm having wallgirders in one direction and beams in the other direction, consist of six variations under combinations of three types of wallgirder height, two types of column transverse reinforcement ratios and two types of lateral loading program. One-directional loading type means reversal loading a alternately in the wallgirder direction and the beam direction. Two-directional loading type means cyclic loading as the tops of columns are displaced with elliptical orbits.According as deformable length of the columns became short using by large depth of wallgirders, experimental column shear force at bending strength was larger than calcurate valure because required lotations in the yield hinge zones weregreater. Consequently such columns with shear reinforcement required by ordinal shear strength design failed in shear in the wallgirder direction. However such columns with high shear reinforcement exhibited bending strengthand deformability. The maximum values of curvature or strain of axial column bars in wallgirder direction appeared at the slightly outer sides of opening portions in the columns, and ones in beam direction appered at the ends of columns. Ulimate bending strength and ductility under two-directional lateral loading were smaller, but energy absorption of hysteresis loops was larger in comparison with those under one-directional loading, respectively.