Study on Ultimate Shear Strength and Shear Design Equation for the Spirally Reinforced Concrete Columns

本研究的目的是澄清以下的项目，并根据28个循环加载测试进行（在每个14个系列中分成2个，比例约为全尺寸的1/3）带有螺旋线漏斗的柱规格.1）以确定带有螺旋线漏斗的定量确定因素的最大剪切强度的影响.2）要审查实验性equation_0 @和多个国家的代码equation_0 @以最近测试日期为基础的强化混凝土列的明显强度，结果被汇总为以下：（1）与螺旋桨挂钩的八柱的裂缝和剪切失败的现象与那些带有正方形挂钩的正常柱相似。（2）与混凝土强度（Fc）、轴负荷（N）、螺旋强化比和长线性强化比。最后的剪切强度被分解为由于其增加的原因 ... More column height。这些力量与那些正方形的柱子相似。（3）八角形柱的剪切强度可以被计算和保守地使用现有的剪切强度等式来替换八角形部分，使相同的面积和相同的强化。（4） The test results indicate that the shear carried by truss Mechanism involving spiral reinforcement （Qut） is well represented by the 45 truss model and the remainder shear can be expressed by the （1+<eta>_0） times of the shear carried by arch Mechanism （Qua）。Where<wta>_0是轴向压缩压力因子（=N/A·Fc， A是列的交叉区域）。对强化混凝土柱的剪切强度相等， Qu（=Qut+Qua），与B方法相同，现在是日本建筑研究所新的剪切设计相等的一个人。（5）当前的经验当量和若干国家的代码当量的权重被调查到118个最近期试验的可用日期。As mentioned in （4）， the modified shear design equation of the AIJ [Qu=Qut+（1+<eta>_0）Qua] is in better agreement with test date。Less（低）

The purpose of this study is to clarify the following items, according to the cyclic loading tests on 28 (divided into 2 series in each 14, scale is about 1/3 of full-size) column specimens with spiral hoops.1) To determine quantitatively certain factors' influences on the ultimate shear strength of reinforced concrete octagonal columns with spiral hoops.2) To review the suitability of the experimental equations and several countries' code equations for shear strength of reinforced concrete columns based on the recent test date.The results are summarized as follows:(1) the phenomena of cracking and shear failure for the octagonal columns with spiral hoops are similar to those of the normal columns with square hoops.(2) The ultimate shear strength of the spirally reinforced concrete columns increased with the increasing of concrete strength (Fc), axial load (N), spiral reinforcement ratio and longitudinal reinforcement ratio. The ultimate shear strength decreased with the increasing of … More column height. These strengths are similar to those of square columns.(3) The shear strength of octagonal columns can be calculated conservatively using the existing shear strength equations by replacing the octagonal sections with squares having the same gross area and same reinforcement.(4) The test results indicate that the shear carried by truss mechanism involving spiral reinforcement (Qut) is well represented by the 45゜ truss model and the remainder shear can be expressed by the (1+<eta>_0) times ofthe shear carried by arch mechanism (Qua). Where <wta>_0 is the axial compressive stress factor (=N/A・Fc, A is the cross-sectional area of column). The shear strength equation for reinforced concrete columns, Qu(=Qut+Qua), is as the same as the B method, which is the one now under consideration for a new shear design equation in the Architectural Institute of Japan.(5) The current empirical equations and several countries' code equations for shear strength are investigated according to 118 available date of the most recent experiments. As mentioned in (4), the modified shear design equation of the AIJ [Qu=Qut+(1+<eta>_0)Qua] is in better agreement with test date. Less