Evaluation and Design Requirements for RC "Gravity" Columns

9416441摩尔在建筑抗震设计中，通常的做法是假定建筑物的一部分抵抗所有地震力，而建筑物的其余部分只抵抗重力。虽然规范条款要求重力承载系统的设计应能适应所施加的侧向漂移，但目前尚不清楚检查所施加的漂移的程序是否足够，也不确定许多工程师是否真的检查重力系统是否存在侧向漂移。以这种方式设计的几座钢筋混凝土(RC)建筑遭受了与所谓重力柱(不是为抵抗侧向力而设计的柱)的故障相关的损坏和倒塌。该项目旨在加深对钢筋混凝土重力柱失效因素的理解，并开发改进的设计方法。这一需要与现有建筑的评估和升级有关，与新建筑的设计同样相关。拟议的研究将使用基于实验证据的分析方法来解决这一需求，并将涉及学术研究人员和设计专业人员。具体来说，研究任务包括：(A)研究钢筋混凝土柱的变形能力；(B)研究实际建筑系统对柱的变形要求；(C)检查设计和评估的实用程序；(D)将研究结果转移到相关的规范/指南活动；(E)协调与正在进行的NSF R/R计划有关的其他北岭研究项目；以及(F)为NEHRP机构将汇编的专业论文系列以及其他出版物和专业演示文稿做出贡献。这是一个北岭地震项目。***

9416441 Moehle It has been common practice in building seismic design to assume part of the building resists all the seismic forces and the remainder of the building resists only gravity forces. Though code provisions require the gravity-load- carrying system to be designed to accommodate the imposed lateral drifts, it is not clear that the procedures for checking the imposed drifts are adequate, and it is not certain that many engineers actually check the gravity system for lateral drifts. Several reinforced concrete (RC) buildings designed in this way sustained damage and collapse associated with failure of the so-called gravity columns (the columns not designed to resist lateral forces. This project is to develop improved understanding of the factors leading to failure of RC gravity columns, as well as to develop improved designed approaches. This need is relevant to evaluation and upgrading of existing buildings, and equally relevant to the design of new buildings. The proposed research will address this need using analytical methods based on experimental evidence, and will involve both academic researchers and design professionals. Specifically, the research tasks include: (a) study of the deformability of reinforced concrete columns; (b) study of deformation demands imposed on columns by practical building systems; (c) examination of practical procedures for design and evaluation; (d) transfer of findings to relevant code/guidelines activities; (e) coordination of other Northridge research projects that are related to the ongoing NSF R/R program; and (f) contribution to the professional papers series to be assembled by NEHRP agencies, as well as other publications and professional presentations. This is a Northridge earthquake project. ***