Effect Of Combined Plan, Vertical And Mass Irregularity On Torsional Performance Of High Raised Buildings

  S K Shanawaz,  S. Amaresh Babu

Recently, reports showing the damage caused by earthquakes indicate that, torsional effects often cause considerable damage to structures leading to their collapse. The response of asymmetric buildings towards torsion is one of the most crucial factors for their damage. Torsion in such buildings is due to irregularity in plan, mass and stiffness which may cause severe damage in structural systems. Due to various reasons structures acquire asymmetry. Asymmetric structures have irregular distribution of plan, stiffness and mass, its centre of mass and centre of rigidity do not coincide and hence cause the torsional effect on the structures which is one of the most important factor influencing the seismic damage of the structure. For the purpose of study, asymmetrical buildings of 12 storeys, 15 storeys and 18 storeys with same columns sizes subjected to gravity loads and seismic loads are analysed using non-linear dynamic analysis. The structure is evaluated in accordance with IS 456-2000 and seismic code IS: 1893-2002 using non-linear time history method with the help of ETABS. Percentage of torsion and joint rotation are significantly decreased by minimizing the stiffness eccentricity. Torsion reduces to 72%, 76% and 72% for 12 storey U shaped building, 15 storeys U shaped building and 18 storeys U shaped building. Similarly torsion reduces to 79%, 85% and 90% for 12 storey building with openings, 15 storey building with openings and 18 storey building with openings. Joint rotation reduced to 84%, 58%, and 65% for 12 storey U shaped building, 15 storeys U shaped building and 18 storeys U shaped building. Joint rotation reduced to 78%, 75 %, and 86% for 12 storey building with openings, 15 storey building with openings and 18 storey building with openings. Thereby a maximum decrease in torsion is 90% for 18 storey building with openings. And maximum decrease in joint rotation is 86% for 18 storey building with openings.

Keywords- Plan irregularity, Vertical irregularity, Mass irregularity, Torsion

Unique Identification Number - IJEDR1904064
Page Number(s) - 361-371
Pubished in - Volume 7 | Issue 4 | December 2019
DOI (Digital Object Identifier) -   
Publisher - IJEDR (ISSN - 2321-9939)

  S K Shanawaz,  S. Amaresh Babu,   "Effect Of Combined Plan, Vertical And Mass Irregularity On Torsional Performance Of High Raised Buildings", International Journal of Engineering Development and Research (IJEDR), ISSN:2321-9939, Volume.7, Issue 4, pp.361-371, December 2019, Available at :http://www.ijedr.org/papers/IJEDR1904064.pdf