Abstract:
The major cause for structures failure during earthquakes is irregular configuration of buildings.
Earthquake damages initiates due locations of structural weaknesses present in multi-storied
framed buildings.
Now a days opening in the floors is common for different reasons like stair cases, lighting,
architectural aesthetics and other. The main objective of this research is to analyze the effect of
the openings in slabs at different location, at different size of opening and different opening shape
of U –shaped building. To see the effect of this regular in elevation and irregular in plane U-shape
buildings are modeled with diaphragm discontinuity and without diaphragm discontinuity building
is analyzed by finite method analysis that is ETABS V.19 software. The design has been done based
on the rules specified in the ESEN 1998:2016 which has been the reference standard. Responses
quantities like; storey displacement, storey drift, storey force, and base shear are carried out for
different shape, size and location of opening of diaphragm through response spectrum analysis.
In this research parametric study has been conducted using same parameters including seismic
location, ground type, and ductility class, loading condition, behavior factor same ductility class
(DCM), and material type for all models. A G+4 total of 13 different models were analyzed and
compared carried out and the findings results are concluded as follows:
For same cross sectional area and shape on different opened down positions of slab opening at
Y-shorter front edge frames showed the maximum reduction storey displacement as compared to
other frames it reduce top storey displacement by 6.50% and 2.80% in the X and Y direction
respectively and the base shears of opening at y-longer corner (M4) have decreased 8.09% to the
x-direction and 8.92% y-direction than without diaphragm discontinuity.
For the same opening position with different cross sectional area of slab that is 4*4 open down
area shows better performance in reduction of displacement than diaphragm without discontinuity
frame. Percent reduction of top storey displacement for 4*4 open down slab size area frame shows
4.2% X direction and 2.8% and Y.. For this specific model 4*4 area opened frame decrease the
base shear by 7.87% in the X direction and 8.75% in the Y direction. But for the same opening
position with the same cross sectional area of opening and different shape of opening there is no
effect on displacement , drift and base shear both in x and y directions
