Seismic Strengthening of URM Buildings by Steel Bracing

该项目得到了 第二阶段（第二年）计划 地震修复和 康复倡议（NSF 90- 23）。 有大量的老年人 配筋砌体建筑 位于高地震区 在全国各地， 设计和详细说明不适用于 足够的横向强度和 现行规范规定的延性 标准 这些建筑构成了 在中度 或者说是地震， 许多这样的人所遭受的损害， 1987年Whittier 1989年洛马普列塔地震 地震 其中一些 正在对建筑物进行评估， 使用几种不同的 技术，钢支撑和 这是广泛使用的方案之一。 然而，没有 抗震试验研究 砌体墙撑性能 强循环系统 变形和有理 其设计程序， 将确保令人满意的性能 在一次严重的地震中。 一项联合合作研究工作 进行了研究， 砌体抗震性能 钢筋加固墙 振奋精神 其目标是 通过测试和 分析，目前使用的哲学 和设计程序，并 开发改进的方法， 加强现有建筑物， 使用延性钢支撑系统 以提高他们在 未来强震“设计 水平”强度。 的调查结果 拟议的研究将是有益的 制订守则规定 评估和加强 现有的URM建筑。

This project is supported under the Phase II (Second Year) program of the Seismic Repair and Rehabilitation Initiative (NSF 90- 23). There is a large inventory of older reinforced masonry (URM) buildings located in high seismic regions throughout the country which were not designed and detailed for adequate lateral strength and ductility as per current code standards. These buildings pose the greatest life hazard during moderate or severe earthquake, as attested to by damage suffered by many of such buildings during the 1987 Whittier earthquake and the 1989 Loma Prieta earthquake. A number of these buildings are being evaluated and strengthened using several different techniques, steel bracing and being one of the widely used schemes. However, there has been no experimental study on the seismic behavior of masonry wall-bracing systems under severe cyclic deformations and on rational procedures for their design which will ensure satisfactory performance during a severe earthquake. A joint cooperative research effort is conducted to study the in-plane seismic behavior of masonry (URM) walls strengthened with steel bracing. The objectives are to evaluate, through testing and analysis, currently used philosophy and design procedures, and to develop improved methods for strengthening existing buildings by using ductile steel bracing systems to enhance their safety during future earthquakes of severe "design level" intensities. The findings of the proposed study will be useful for formulation of code requirements for evaluation and strengthening of existing URM buildings.