Strength and Stiffness-Based Methods for Reducing Hinging in Columns of Reinforced Concrete Frames Subjected to Strong Ground Motion

本计画针对强震作用下钢筋混凝土框架柱之铰振问题，进行以强度与刚度为基础之研究。 目前的规定，以减少铰链形成的可能性，在一个框架的列要求的总弯曲能力的列框架到一个关节超过的大梁。 本项目的研究将为框架构件制定具体的强度和刚度准则，以消除框架关键区域的柱屈服，并在强烈地面运动反应期间提供最小的局部变形。 将开发一个分析程序，包括构件刚度和不同的强度和刚度性能的高度结构。 研究中还将考虑具有软层的结构。 将确定两种情况的标准，一种是消除任何柱的屈服，另一种是将屈服限制在指定的“最佳”建筑物高度水平。 所选标准将使用一系列具有非线性静态和动态分析的比例框架进行评估。 此外，将根据现有属性和修改后的属性分析北岭地震期间安装的几个现有框架，以满足拟定标准。 这项研究有望为建筑框架提供新的强度和刚度标准，这将降低建筑框架关键位置柱屈服的概率。

This project carrier out an investigation of strength and stiffness-based methods to reduce hinging in columns of reinforced concrete frames subjected to strong ground motion. Current provisions to reduce the likelihood of hinges forming in the columns of a frame require that the total flexural capacity of the columns framing into a joint exceed that of the girders. The effectiveness of this criterion is limited by the uncertainty of actual member flexural capacities under dynamic loads.The research under this project will develop specific strength and stiffness criteria for frame members so as to eliminate yielding in columns in critical regions of a frame and provide minimum localized distortions during response to strong ground motion. An analytical procedure will be developed to include member stiffness and varied strength and stiffness properties over the height of the structure. Structures with soft stories will also be considered in the study. Criteria will be identified for two situations those that would eliminate yielding of any column, and those that would limit yielding to a specified "optimum" level of building height. The selected criteria will be evaluated using a series of proportioned frames with nonlinear static and dynamic analyses. In addition, several existing frames that were instrumented during the Northridge earthquake will be analyzed based on the existing properties and properties modified to satisfy the proposed criteria. This study is expected to provide new strength and stiffness criteria for building frames that will reduce the probability of columns yielding in critical locations of the building frame.