STUDIES IN EARTHQUAKE LOAD-GRAVITY FRAME INTERACTION

Abstract

RC floor systems are generally framed into a system of RC columns to obtain multi-storey buildings. For medium rise buildings (up to 20-story about), framed RC columns are the main structural sub-system out of the many choices available for vertical systems. These vertical systems are required to resist lateral loads (Wind, Earthquake) along with the gravity loads from the floors. Although, the gravity loads constitute the main loads for the vertical system, from design point of view, the influence of lateral loads rapidly increases with the increase in number of stories (height). Appropriate incorporation of lateral loads in the analysis process, thus, becomes essential. A comparative study of various seismic loading standards provides knowledge of the sophistication in seismic load provisions and leads to a better understanding of the specifications. Analysis of frames needs extensive use of computer with a lot of pre-and-post processing of data. Approximate methods of analysis have proved to be quite useful for preliminary analysis of frames subjected to lateral loads. This dissertation primarily deals with the assessment of seismic loads on frames followed by a study of the applicability of approximate analysis for plane frames of various characteristics. The study has been carried out using the computer programs specially written for this purpose. The programs have been developed in the Microsoft Visual Basic programming language. Two different frames with different number of bays have been used for the study of seismic loads as obtained by various seismic loading codes. These frames, for a particular loading have been studied for comparison of results obtained from various methods of analysis. Relevant observations and conclusions arrived at are reported