Some Parameters Affecting the Behaviour of R.C. Frames Designed for Gravity Loads Only and Subjected to Earthquakes

Abstract

Time history analysis was performed to study the effect of selected parameters in the behaviour of reinforced concrete frames under earthquake loads. The RC frames were designed for gravity-loads only as typically found in most seismic prone countries before the introduction of adequate seismic design code provisions. The parameters considered in this study were the number and span of bays, the number of stories, and the presence of infill wall (full infilled frame and infilled frame with open ground stories). It was observed that the presence of infill wall may affect the seismic behaviour of frame structure to large extent, and the infill wall increases the strength and stiffness of the structure. Also it was observed that infilled frames are preferred in seismic regions than the open ground story ones, because the story drift of first story in open ground story frames is very large than the upper stories, this may probably cause the collapse of structure.

Roof Lateral Displacement for Gravity Load Designed Rc Frames Subjected to Earthquakes

“…The roof lateral displacement is very significant parameter in performance based engineering and should be within acceptable limits as per the requirement of different performance levels. Hence in this study, a focus is given to propose an expression for estimating the roof lateral displacement for RC frames designed for gravity load only (GLD) by using and analyzing the results obtained in a previous study [9] done by the authors for a series of GLD RC with different number of bays, different number of stories, different bay spanned three types of presences of infill (bare frame "BF", infilled frame "IN" and infilled frame with open ground story "OG"). The data will be analyzed using a statistical program called SPSS 16.0 in order to propose an expression to estimate the roof lateral displacement for three types of GLD RC; bare frame, infilled frame and infilled frame with open ground story.…”

“…In our previous study [9], time history analysis was performed to study the effect of selected parameters in the behavior of reinforced concrete frames under earthquake loads. A series of multistory RC frames were designed for gravity loads only (1.4D.L+1.7L.L) without considering the seismic loads as typically found in most seismic prone countries before the introduction of adequate seismic design code provisions.…”

“…The detailing for the structure was in accordance with the general non-seismic provisions of the ACI 318-89 Code [11]. for more details see references [9] and [12] It should be noted here that for differentiating between each models, a Model_ID was given for all models to describe the model's number of stories, number and span of bays and the type of infill. The Model_ID is composed of three parts, the first part consists of number followed by the letter "S" expresses the number of stories and the second part consists of letter "B" preceded by a number that represents the number of bays, where the number that follows the letter "B" represents the bay length, while the third part indicates the existence of masonry infill or not ("BF": without infill, "IN": full infill in all stories and "OG": open ground story and with infill in all others stories).…”