Strengthening and Repair of Nonductile Reinforced Concrete Frames Using External Steel Jackets and Plates (Collaborative Research)

该项目得到了美国国家科学基金会第90-23号公告“结构抗震修复与恢复研究”的支持。对抗震能力不足的既有建筑进行加固是地震工程领域亟待解决的问题。被确认为构成最大地震危险之一的现有结构的一大类是非延性混凝土框架。混凝土框架的一些加固技术包括增加结构墙，增加钢支撑，以及使用钢筋混凝土夹套扩大柱和梁。混凝土夹套的另一种方法是使用外部钢夹套和附着在现有构件上的钢板。与使用混凝土夹套相比，钢夹套可以提供显著的优势，减少劳动力，降低成本，并减少对现有设施的破坏。拟议的研究计划将调查与使用外部钢套和钢板加固非延性混凝土框架有关的关键问题。该项目包括一些相互关联的试验，分为三个主要阶段：I-钢-混凝土连接的性能；II-钢套加固的单个构件的性能；III-钢套加固的梁柱组件的性能。该项目的总体目标是制定有效实施钢套作为加固和维修技术的设计准则。该项目是一个学术机构和两个专业工程办公室共同努力将研究成果付诸实践的合作研究活动的一部分。

This project is supported under NSF Announcement NO. 90-23, "Repair and Rehabilitation Research for Seismic Resistance of Structures." The need to strengthen existing buildings with inadequate seismic resistance is an urgent problem in the field of earthquake engineering. A major class of existing structures identified as posing one of the greatest seismic hazards are nonductile concrete frames. A number of strengthening techniques for concrete frames include addition of structural walls, addition of steel bracing, and enlarging of columns and beams using reinforced concrete jackets. An alternative approach to concrete jackets is the use of external steel jackets and plates attached to the existing members. Steel jackets may offer significant advantages of reduced labor, reduced cost, and reduced disruption to existing facilities, as compare to the use of concrete jackets. The proposed research program will investigate critical issues associated with the use of external steel jackets and plates for strengthening nonductile concrete frames. The project consists of a number of interrelated tests, divided into three major phases: I - behavior of steel-to-concrete connections; II - behavior of individual members strengthened with steel jackets; and III - behavior of beam-column subassemblages strengthened with steel jackets. The overall objective of the project is to develop design guidelines for the effective implementation of steel jackets as a strengthening and repair technique. This project is one part of a collaborative research activity involving an academic institution and two professional engineering offices in a common effort to implement research results into practice.