Evaluation and Design Requirements for Reinforced Concrete "Gravity" Columns

9416533霍姆斯在建筑物抗震设计中，通常的做法是假设建筑物的一部分抵抗所有的地震力，而建筑物的其余部分只抵抗重力。 尽管规范规定要求重力承载系统的设计应能适应施加的侧向漂移，但尚不清楚检查施加漂移的程序是否充分，也不确定是否有许多工程师实际检查重力系统的侧向漂移。 一些钢筋混凝土（RC）建筑物以这种方式设计的持续损坏和倒塌与失败的所谓的重力柱（柱不设计抵抗横向力）。 本计画旨在增进对钢筋混凝土重力柱破坏因素的了解，并发展改良的设计方法。 这一需要与现有建筑物的评估和升级有关，同样也与新建筑物的设计有关。 该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。 具体地说，研究任务包括：（a）钢筋混凝土柱的变形能力研究;（B）通过设计和评估的实际程序对柱施加的变形需求研究;（d）将研究结果转移到相关的规范/指南活动中;（e）与正在进行的NSF R/R计划有关的其他北岭研究项目的协调;以及（f）为NEHRP机构汇编的专业论文系列以及其他出版物和专业演讲做出贡献。 这是北岭地震项目。 ***

9416533 Holmes 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 design approaches. This need is relevant to evaluation and upgrading of existing buildings, and equally relevant to the design of new buildings. The 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 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. ***