Investigation of The Critical Angle of Seismic Incidence for The Seismic Safety Assessment of Asymmetric Reinforced Concrete Buildings with Re-Entrant Corner Plan Configurations
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Date
2018-11
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Publisher
AAU
Abstract
In this thesis, the methodology to estimate the possible critical angle of seismic incidence
and its corresponding structural demand has been investigated in the context of LTHA, to
assess the seismic behavior of asymmetric reinforced concrete buildings with re-entrant
corner plan configurations under different orientations of seismic excitation. This was
done by defining the structural demand as the function of input seismic incidence angle
( ) with in the range (0
0
, 180
0
) at 15
0
increment, in order to assess the seismic incidence
angle that leads to the maximum global and local structural demand of reinforced
concrete buildings under different orientations of seismic excitation. To do so, different
3D computer model of single and four-story symmetric (torsionally stiff) and asymmetric
(torsionally flexible) reinforced concrete buildings has been generated with the aspect of
changing plan configuration. Finite element based linear time history dynamic analysis
were carried out to assess seismic response of the structural model in all cases with the
help of elastic demands (maximum story drift, and maximum column axial force, torsion
& moment), by using ETABS.V16 software.
It is observed from the study that, the structural demand produced varies as a function of
input seismic incidence angle and the highest demand occurs in the most flexible
structural direction. The structure gets its maximum value of column axial forces, torsion
and moment with a specific angle of seismic excitation which is different for different
shapes of building as well as from column to column. It is concluded from the study that
the angle of seismic incidence input motion considerably influences the response of RC
structures. Additionally, considering ASIcri values of all models, asymmetric buildings
with re-entrant plan have shown considerable change in maximum column axial forces
and moment due to the change in building plan configurations & column locations. But,
among various internal forces irregular buildings with re-entrant corner plans are more
sensitive to the maximum column torsion when compared with corresponding regular
building.
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Keywords
Seismic incidence angle, re-entrant corner plan, linear response history analysis