Abstract:
Choosing the most efficient and economical lateral load resisting system is a
crucial question in designing high rise buildings, especially in high seismic zones. Shear
walls and steel bracings are most popular lateral load resisting systems. Recently the use
of diagrids for structural efficiency and architectural elegance has generated renewed
interest from architectural and structural designers. These structures are emerging as
popular structural systems in many developed and developing countries of the world, but
in context of our country they are yet to get importance. To transfer the technology of
using diagrids as lateral load resisting system to our country , it is very crucial to study
the advantages of them over the well-known lateral load resisting systems.
This research is a comparative study, considering a symmetrical G+30 office high rise RC
building laterally strengthened by 14 lateral load resisting systems collectively of six
different types of shear wall, six different types of steel bracing, rigid frame and four
module diagrid. Modal response spectrum analysis for seismic zone IV was carried out
based on ESEN 1998-1:2013 using finite element software ETABS v9.6.0. Every
independent variable that can affect lateral load resistance of high rise buildings was kept
constant except the lateral load resisting systems. The comparison was in terms of four
critical parameters; storey displacement, storey drift, time period and base shear.
As per the comparisons made, diagrids have showed a reduction of 7.8% in the X direction
and 6.9% in the Y direction in storey displacement, 9.74% in the X direction and 7.31% in
the Y direction in storey drift and 8.87% in fundamental time period as compared to the
most efficient lateral load resisting system considered in the study. They showed a
reduction in base shear of 8228.79KN in the X direction and 9418.25KN in the Y direction
as compared to the system with the least base shear considered in the study (bare frame).
These results show the best performance of diagrids in terms of reduction in storey
displacement, storey drift, time period and base shear for every case and from every
lateral load resisting system considered in the study. Therefore, diagrids, in addition to
their inherent aesthetic quality and geometrical versatility, are the most efficient lateral
load resisting systems in the range of many lateral load resisting systems known.
