Effect of sequential earthquakes on evaluation of non-linear response of 3D RC MRFs

IF 1.4 4区工程技术 Q3 ENGINEERING, CIVIL

Earthquakes and Structures Pub Date : 2021-03-01 DOI:10.12989/EAS.2021.20.3.279

P. Oggu, K. Gopikrishna

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引用次数: 0

Abstract

Most of the existing seismic codes for RC buildings consider only a scenario earthquake for analysis, often characterized by the response spectrum at the specified location. However, any real earthquake event often involves occurrences of multiple earthquakes within a few hours or days, possessing similar or even higher energy than the first earthquake. This critically impairs the rehabilitation measures thereby resulting in the accumulation of structural damages for subsequent earthquakes after the first earthquake. Also, the existing seismic provisions account for the non-linear response of an RC building frame implicitly by specifying a constant response modification factor (R) in a linear elastic design. However, the 'R' specified does not address the changes in structural configurations of RC moment-resisting frames (RC MRFs) viz., building height, number of bays present, bay width, irregularities arising out of mass and stiffness changes, etc. resulting in changed dynamic characteristics of the structural system. Hence, there is an imperative need to assess the seismic performance under sequential earthquake ground motions, considering the adequacy of code-specified 'R' in the representation of dynamic characteristics of RC buildings. Therefore, the present research is focused on the evaluation of the non-linear response of medium-rise 3D RC MRFs with and without vertical irregularities under bi-directional sequential earthquake ground motions using non-linear dynamic analysis. It is evident from the results that collapse probability increases, and 'R' reduces significantly for various RC MRFs subjected to sequential earthquakes, pronouncing the vulnerability and inadequacy of estimation of design base shear by code-specified 'R' under sequential earthquakes.

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连续地震对三维RC MRF非线性响应评价的影响

大多数现有的钢筋混凝土建筑抗震规范只考虑场景地震进行分析，通常以指定位置的反应谱为特征。然而，任何真正的地震事件通常都涉及在几个小时或几天内发生多次地震，其能量与第一次地震相似甚至更高。这严重损害了恢复措施，从而导致第一次地震后后续地震的结构损伤累积。此外，现有的抗震规定通过在线性弹性设计中指定恒定响应修正系数（R），隐含地说明了RC建筑框架的非线性响应。然而，规定的“R”并没有解决RC抗弯框架（RC MRF）结构配置的变化，即建筑高度、存在的开间数量、开间宽度、质量和刚度变化引起的不规则性等，从而导致结构系统的动态特性发生变化。因此，考虑到规范规定的“R”在RC建筑动态特性表示中的充分性，迫切需要评估连续地震动下的抗震性能。因此，本研究的重点是使用非线性动力学分析来评估具有和不具有垂直不规则性的中高层三维RC MRF在双向连续地震地面运动下的非线性响应。从结果中可以明显看出，在顺序地震作用下，各种RC MRF的倒塌概率增加，“R”显著降低，表明在顺序地震下，用规范规定的“R”估算设计基底剪力的脆弱性和不足性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Earthquakes and Structures ENGINEERING, CIVIL-ENGINEERING, GEOLOGICAL

CiteScore

2.90

自引率

20.00%

发文量

审稿时长

>12 weeks

期刊介绍： The Earthquakes and Structures, An International Journal, focuses on the effects of earthquakes on civil engineering structures. The journal will serve as a powerful repository of technical information and will provide a highimpact publication platform for the global community of researchers in the traditional, as well as emerging, subdisciplines of the broader earthquake engineering field. Specifically, some of the major topics covered by the Journal include: .. characterization of strong ground motions, .. quantification of earthquake demand and structural capacity, .. design of earthquake resistant structures and foundations, .. experimental and computational methods, .. seismic regulations and building codes, .. seismic hazard assessment, .. seismic risk mitigation, .. site effects and soil-structure interaction, .. assessment, repair and strengthening of existing structures, including historic structures and monuments, and .. emerging technologies including passive control technologies, structural monitoring systems, and cyberinfrastructure tools for seismic data management, experimental applications, early warning and response