Analysis of the Torsional Irregularity as per IS 1893 (Part 1): 2016 and IS 1893 (Part 1): 2002

The earthquake-resistant design of a building begins with its architectural design. Earthquake safety depends on many factors such as type of structural system, distribution of mass, and mechanical properties of structural material used in the construction of buildings. A building with regular configurations suffers much less damage as compared to building with irregular configurations. The irregularity criteria have been modified in the new IS 1893(Part): 2016 which is the sixth revision of the Indian Seismic Code. This paper aims to perform a comprehensive analysis on the torsional irregularity criteria (a type of plan irregularity) as per IS 1893 (Part 1): 2016 and IS 1893 (Part 1): 2002. The irregular buildings with different plans have been modelled by computer software STAAD.Pro Connect Edition and results of torsional irregularity checks as per IS 1893 (Part 1): 2016 and IS 1893(Part 1): 2002 have been compared. The criteria for torsional irregularity check as per new IS1893(Part 1): 2016 is found to be more elaborated and simpler as compared to old IS 1893(Part 1): 2002. New seismic code gives about 2.7 times clearer indication of torsional irregularity in the building model.