International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 07 Issue: 08 | Aug 2020 www.irjet.net p-ISSN: 2395-0072
© 2020, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1617
Study of Optimistic Location of Soft Story in High Rise RC Building
Anuj Bhikanrao Ingle
1
, Dr. S. S. Angalekar
2
1
P.G. Student, Sinhgad College of Engineering Pune, Maharashtra State, India
2
Professor, Dept. of Civil Engineering, Sinhgad College of Engineering Pune, Maharashtra State, India
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Abstract - Now a day’s growth of Multi-story building is
very high because of rapid urbanization all over the world.
Availability of land is minimum due to population, so
people end to construct the multi-story building in
earthquake prone area also. In soft-story buildings the
relative stiffness of the soft-story, typically the bottom
story, is significantly less than upper stories due to the
presence of large openings which reduce the available
space for lateral force resisting system components such
as shear walls. Soft story is generally provided for parking,
concert hall, Cinema Theater, barn or any purpose in
multi-story building, though multi-storeyed buildings with
soft storey floor are inherently vulnerable to collapse due
to earthquake. This depends on various factors effects on
the behavior of multi-story building i.e. irregularity in plan
and elevations, uneven distribution of mass etc. To study
of different location on the seismic behavior of multi-story
building, linear dynamic analysis (Response spectrum
analysis) in ETABS software is carried out for Zone IV. In
this project an investigation has been made to study the
seismic behavior of soft storey building with different
arrangement in soft storey building with shear wall and
bracings. This analysis is with consideration of strength
and stiffness in the upper storey and with and without
consideration of braces in the ground storey. Different
seismic parameters like time period, story shear, story
displacement and story drift are checked out.
Key Words: Earthquake, Response Spectrum analysis,
soft story, shear wall, bracing.
1. INTRODUCTION
An earthquake is the result of a sudden release of energy
in the earth’s crust that creates seismic waves. The seismic
activity of an area refers to the frequency, type and size of
earthquake experienced over a period of time. At the
earth’s surface, earthquake occurs itself by shaking and
sometimes displacement of the ground. When the
epicentre of a large earthquake is located offshore, the sea
bed may be displaced sufficiently to cause a tsunami.
Earthquakes can also trigger landslides and occasionally
volcanic activities.
An earthquake is measured by seismometers. An
earthquake having magnitude of less than 5 are generally
measured by Richter magnitude scale & that of magnitude
up to 9 or more then 9 is measured by modified Mercalli
scale. In its most general sense, the word earthquake is
used to describe any seismic event, whether natural or
caused by humans that generate seismic waves.
Earthquakes are caused mostly by rupture of geological
faults, but also by other events such as volcanic activities,
landslides, blasts and nuclear tests. An earthquake’s pint
of initial rupture is called its focus or hypocenter. The
epicenter is the point at ground level directly above the
hypocenter.
Benavent-Climent and S. Mota-Páez (2017)
investigated a solution for the seismic upgrade of existing
reinforced concrete frames with open first story and
masonry infills at the upper stories. It combines the
addition of hysteretic dampers with the strengthening (if
necessary) of the columns of the first story. The energy-
based design procedure put forth provides the strength,
stiffness and energy dissipation capacity required for the
dampers so that the overall structure can endure the
design earthquake without exceeding a prescribed
maximum drift at the first story. Non-linear time history
analyses conducted on two prototype structures subjected
to thirty ground motions showed that the performance of
the retrofitted structures is satisfactory, and the proposed
procedure provides for a safe-side and not excessively
conservative dimensioning of the dampers. The mean-plus
standard deviation of the first story drift obtained from
the analyses roughly coincides (about 8% lower) with the
target drift used for designing the dampers. The
probability of having first story drifts larger that the target
drift is very low (13%), and in no case the target drift was
exceeded by more than 20%. The maximum shear forces
in the upper stories predicted with the proposed formulae
coincides approximately with the upper bound of the
responses obtained from the time history analyses. The
residual drift at the first story is less than 0.05% for 83%
of the ground motions.
Adrian Fredrick C. Dyaa and Andres Winston C.
Oretaaa (2015) have studied the Seismic vulnerability
assessment of soft story irregular buildings using
pushover analysis .Preliminary seismic risk assessment
tools were used to screen existing buildings against
potential seismic hazards. Buildings that perform poorly
were prioritized for detailed evaluations to determine its
condition. The risk of a building can be defined as the
product of Hazard, Vulnerability, and Assets. Hazard is the
earthquake itself. Vulnerability are building characteristics
that make it more susceptible to the hazard. Upon analysis
of the modelling results for the soft story building, they
have concluded that the main cause for soft story buildings