INFLUENCE OF TIMESPANS ON CONSTRUCTION SEQUENCE ANALYSIS OF RC BUILDINGS

Abstract

The sequence of construction, application of loads, and its timings are significant for the method of Construction Sequence Analysis (CSA). Any variation in these parameters significantly changes the responses of reinforced concrete (RC) structures, even without considering the effect of time-dependent properties of concrete like creep and shrinkage. When the effect of these factors is incorporated, the change in timespan has a significant impact on the overall responses of the structure. Many researchers have considered the response at the time of application of live load. This study indicates that it may lead to failure as it is less than the critical responses. The prevailing practice in India is to design RC buildings for 50 years of life span. In this study, responses like the axial shortening of columns and the bending moments at various sections of a selected beam of a 40 storeyed RC building are observed for the selected nine different timespans ranging from one to fifty years considering the effect of creep and shrinkage. These responses are compared with the response of the 50th year to arrive at a critical time span for analysis. The analysis is done on the MIDAS Gen-17 software. This study concludes that 98% to 99% of the 50th year responses are achieved within 30 years from the application of live load. The study recommends analyzing RC structures only up to the timespan of 30 years using the CSA method.