Civil Insight: A Technical Magazine Volume 2 | Page 16

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TEACHERS’ SECTION
CIVIL INSIGHT 2018
Ground motion detail
Gorkha earthquake-2015 recorded in Institute of Engineering, Pulchowk campus, Lalitpur Patan station,retrieved
from (Taika et al., 2016) is used for the analysis.
RESULT AND DISCUSSION
Base shear and story shear of irregular buildings were compared to regular buildings. Regular building shaving
regular distribution of mass in vertical direction and irregular i th story indicates the mass irregularity is introduced
in i th fl oor of that building model. Mass irregularity was introduced, increasing live load of that particular story.
Consequently two cases are considered here; one having 200% and another having 300% mass irregularity.
Base/Story shear comparison
Figure 3: Base and Story shear distribution in X-direction in 200%
mass irregular case
Figure 4: Base and Story shear distribution in X-direction in 300% mass irregular case
Regular building base shear is 775 kN and 1128 kN in X and Y direction respectively when mass irregularity is
of 200%. Maximum base shear is yielded when 4 th story is irregular in X and 3 rd story irregular in Y-direction.
Base shear yield is higher when irregularity is in 4 th and 5 th story for 200% mass irregular case. In 300% mass
irregular case, maximum base shear yields when irregularity is in 3 rd story.