Evaluation of Existing Reinforced Concrete Columns

这个项目是与卢瑟福公司的W.Holmes的一个配套项目合作完成的。Chekene(国家科学基金会赠款编号9120214)是在地震修复和恢复倡议(国家科学基金90-23)第二阶段(第二年)计划下支持的。在20世纪70年代S之前建造的钢筋混凝土框架是造成人员伤亡的最大危险之一，因为在强烈的地面震动中倒塌。这种结构的主要缺陷之一是柱子的比例和细节不够充分。缺陷的例子包括柱强度相对于梁的强度不足，横向配筋较轻，和短搭接。本研究旨在对缺陷柱的受力性能进行试验研究，并提出计算缺陷柱强度和变形能力的方法。供结构工程师使用的现有柱。这些方法将有助于(A)评估现有结构和(B)用于设计旨在保护相对现有结构的脆性元素。这项研究包括对现有钢筋混凝土柱性能数据的详细审查，对现有结构中常见细节的研究，对含有现有结构中发现的缺陷的柱进行试验、数值模拟和结果分析，并制定了一套实用的规则，用于测量现有结构中钢筋混凝土柱的强度和变形性。这项研究将由加州大学伯克利分校和卢瑟福切肯大学的研究人员/工程师联合进行。

This project, in collaboration witha companion project by W. Holmes of Rutherford & Chekene (NSF Grant No. 9120214), 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.