Civil Insight: A Technical Magazine Volume 3 | Page 48

Karki G. and Bhatt M.R.
Civil Insight (2019) 45-50
Thus, to obtain collapse mechanism for this study, the pushover analysis was carried out as per FEMA-356,
ATC-40, and also using the concepts described by Krawinkler and Seneviratna (1998).
3) Observations and Results
3.1) Comparison of the collapse mechanisms
3.1.1) Analyses of the 3-storied building
From the pushover analyses, as shown in Fig. 4, it is observed that even higher value of column overdesign
factor, which is 2, is not sufficient to achieve complete beam hinge mechanism for the 3-storied building.
For a low-rise building, the size and strength of the column are relatively smaller and weaker than that of
the beam. Generally, the size of beam is taken as 230mm X 355mm and that of column is taken as 300mm
X 300mm for a 3-storied building. This size is generally adopted for similar buildings for designing in
context of Nepal. The presence of slab also enhances the flexural capacity of the beam. Hence, it is
demonstrated that a beam is relatively stronger than a column. Due to the same reason, even for the higher
value of column overdesign factor 2, the failure of a building is due to column sway mechanism.
a) Hinges for cof 1.2
b) Hinges for cof 1.4
d) Hinges for cof 1.8
c) Hinges for cof 1.6
e) Hinges for cof 2
Fig. 4. Analyses of the 3-storied building with varying cof
3.1.2) Analyses of the 9-storied building
As presented in Fig. 5, the scenario is different for the medium-rise 9-storied building, where a significant
beam hinge mechanism is achieved even for smaller values of cof 1.2 and 1.4. However, along with the
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