Evaluation of Existing Reinforced Concrete Columns

本项目与加州大学伯克利分校的J. Moehle的同伴项目（NSF资助号9120061）合作，由地震修复和恢复计划（NSF 90-23）的第二阶段（第二年）计划提供支持。20世纪70年代以前建造的钢筋混凝土框架是在强烈的地面震动中倒塌造成生命损失的最大危险之一。这种结构的主要缺陷之一是柱的比例和细节不足。不足的例子包括相对于梁的强度柱的强度不足，横向钢筋轻，短的搭接。本研究的目的是对缺陷柱的性能进行实验研究，并开发现有结构柱的强度和变形能力的计算方法工程师。这些方法将有助于(a)评估现有结构和(b)设计旨在保护现有结构相对脆弱元素的改造系统。​该研究包括对现有钢筋混凝土柱性能数据的详细回顾，对现有结构中常见细节的研究，在含有现有结构缺陷的柱子上进行的实验、数值模拟和结果分析；并制定了一套实用的既有结构中钢筋混凝土柱强度和变形能力测量规则。这项研究将由加州大学伯克利分校和卢瑟福Chekene的研究人员和工程师共同进行。

This project, in collaboration with a companion project by J. Moehle of the University of California- Berkeley (NSF Grant No. 9120061), is supported under the Phase 2 (second year) program of the Seismic Repair and Rehabilitation Initiative (NSF 90-23). Reinforced concrete frames constructed prior to the 1970's pose one of the greatest hazards for loss of life due to collapse during strong ground shaking. One of the key deficiencies of such structures is inadequate proportioning and detailing of columns. Examples of deficiencies include insufficient column strength relative to beam strength, light transverse reinforcement, and short lap splices. This research is to conduct an experimentally based study of the behavior of deficient columns and to develop methods for calculating strength and deformability of existing columns for use by structural engineers. The methods will be useful (a) for evaluation of existing structures and (b) for design of retrofitting systems that are intended to protect relatively brittle elements of the existing structure. The research includes a detailed review of existing data on performance of reinforced concrete columns, study of common details in existing structures, experiments on columns containing deficiencies representative of those found in existing construction, numerical modeling and analyses of results, and development of a practical set of rules for gaging the strength and deformability of reinforced concrete columns in existing structures. The research will be carried out jointly by researchers/engineers at the University of California at Berkeley and at Rutherford & Chekene.