An Investigation of Coefficient of Torsional Irregularity for Irregular Buildings in Plan

Abstract

AbstractIn many of the structures in the present scenario, most of the buildings have irregular configurations in both plan and elevation of the structure. This irregular configuration in future may subject to damage due to earthquakes. Structures experience lateral deflections under earthquake loads. Asymmetric distribution of mass, rigidity and strength due to irregularity in the design of the building when the building is exposed to translations, and unnecessary floor rotations are the key causes of serious harm to the structures. In most of the research works, it is repeatedly confirmed that irregular structure suffers more damage than regular structure. The code proposed torsional irregularity coefficient does not include eccentricity in the direction of excitation of earthquake. The objective of this work is, first of all, to analyze the requirements for excessive structural irregularity and, secondly, to address the possible irregularity provisions of the code. A parametric investigation is conducted on six types of asymmetrical normal buildings with different floor numbers and structural wall location and six types of unusual L-shaped buildings with different story numbers to accomplish this task. Based on this analysis, the maximum irregularity coefficient found in 1 story structure and torsional irregularity coefficients are found to increase as the number of story in most structures decreases. Also, floor rotation increases with respect to number of floors, as the story numbers increases, floor rotation reach the maximum value.KeywordsTorsional irregularity coefficientRotation of floorIrregular buildings