In the recent years a lot of attention has been given to the earthquake analysis of structure it is one of the most devastating natural calamity and which causes severe damage not only to the properties but also to the lives. This is the reason there has been a lot of focus on the structures to be earthquake resistant. Buildings get damaged mostly due to the earthquake ground motions. In an earthquake, the building base experiences high frequency movements, which results in the inertial force on the building and its components and this problem gets worse when a structure is irregular in shape, size etc,. Therefore, there is a lot to work on the seismic behavior of the irregular building which might not respond the way regular building does. It makes the irregular building quite more complex and unpredictable during the course of an earthquake.

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International Journal of Research and Innovation (IJRI)
International Journal of Research and Innovation (IJRI)
PERFORMANCE BASED ANALYSIS OF VERTICALLY IRREGULAR STRUCTURE
UNDER VARIOUS SEISMIC ZONES.
Mohammed Azemuddin1
, Venkata Ratnam 2
, Mohammed Abdul Hafeez 3
1 Research Scholar, Department of Civil Engineering, Aurora Scientific Technological and Research Academy, Hyderabad, India.
2 Associate Professor, Department of Civil Engineering, Aurora Scientific Technological and Research Academy, Hyderabad, India.
3 Associate professor , Department of Civil Engineering, Maulana Azad National Urdu University, Hyderabad, India.
*Corresponding Author:
Mohammed Azemuddin,
Research Scholar, Department of Civil Engineering,
Aurora Scientific Technological and Research Academy,
Hyderabad India.
Published: July 25, 2015
Review Type: peer reviewed
Volume: II, Issue : II
Citation: Mohammed Azemuddin, Research Scholar
(2015) "PERFORMANCE BASED ANALYSIS OF VERTI-
CALLY IRREGULAR STRUCTURE UNDER VARIOUS
SEISMIC ZONES."
INTRODUCTION
General
Earthquake is a natural phenomenon, which is generated
in the earth’s crust. Duration of the earthquake developed
is generally very short, which might not last more than
few seconds or a minute or so but, it is the intensity of the
earthquake that’s makes the big difference from the mod-
erate damage to the mass destruction. However, it is the
fact that thousands of people lose their lives due to the
earthquake in different parts of the world and this gets
to its peak when this occurs with larger intensity. The ef-
fects of an earthquake are strongest in a broad zone sur-
rounding the epicenter. Surface ground cracking associ-
ated with faults that reach the surface often occurs, with
horizontal and vertical displacements of several yards
common. Such movement does not have to occur dur-
ing a major earthquake; slight periodic movements called
fault creep can be accompanied by micro earthquakes
too small to be felt. The worst damage occurs in densely
populated urban areas where structures are not built to
withstand intense shaking.
Seismic hazard in the context of engineering design is
generally defined as the predicted level of ground accel-
eration which would be exceeded with 10% probability at
the site under consideration due to the occurrence of an
earthquake anywhere in the region, in the next 50 years.
A lot of complex scientific perception and analytical mod-
eling is involved in seismic hazard estimation. A compu-
tational scheme involves the following steps: delineation
of seismic source zones and their characterization, selec-
tion of an appropriate ground motion attenuation relation
and a predictive model of seismic hazard. Although these
steps are region specific, certain standardization of the
approaches is highly essential so that reasonably compa-
rable estimates of seismic hazard can be made worldwide,
which are consistent across the regional boundaries.
Damage and loss of life sustained during an earthquake
result from falling structures and flying glass and objects.
Flexible structures built on bedrock are generally more re-
sistant to earthquake damage than rigid structures built
on loose soil. In certain areas, an earthquake can trig-
ger mudslides, which slip down mountain slopes and can
bury habitations below. So as to avoid these damages the
structure has be built considering the earthquake that it
may experience during its life span. Many methods are
available which can be used to analyze the performance
of the earthquake but the most commonly or the method
which is more popular among structural designers is the
pushover analysis. The pushover analysis predicts the re-
Abstract
In the recent years a lot of attention has been given to the earthquake analysis of structure it is one of the most dev-
astating natural calamity and which causes severe damage not only to the properties but also to the lives. This is the
reason there has been a lot of focus on the structures to be earthquake resistant. Buildings get damaged mostly due
to the earthquake ground motions. In an earthquake, the building base experiences high frequency movements, which
results in the inertial force on the building and its components and this problem gets worse when a structure is irregu-
lar in shape, size etc,. Therefore, there is a lot to work on the seismic behavior of the irregular building which might not
respond the way regular building does. It makes the irregular building quite more complex and unpredictable during
the course of an earthquake.
Pushover analysis is one of the effective tool by which the response of a structure can be understood. The procedure
basically consists of application of lateral loads in increasing order from top story to the bottom story which might follow
a particular pattern and the results obtained from this are compared basically in terms of base shear and roof displace-
ment and further these are used to obtain the performance point of the structure.
The study aims to predict the response of a structure in different zones according to the IS 1893:2002 (part 1) for a G+15
storied building with and without steel cross bracing. The structure is irregular in geometry vertically. The analysis of
he structure has been performed on the SAP 2000 finite element software.
It has been observed that the structure can resist more loads with the inclusion of steel bracings, base shear capacity
of the building is observed to be doubled and the roof displacement of the building has reduced considerably. The base
shear capacity of the building increases with increase in zone factor i.e. from zone ii to zone v. The story drift changes
suddenly at the level of setback due to the large concentration of forces at that level.
Keywords: G+15 storied building, vertical irregularity, pushover analysis, base shear, story drift.
1401-1402

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International Journal of Research and Innovation (IJRI)
sponse of the structure to quite a reliable extent and even
is not that complex in process most of the engineers opt
for pushover analysis due to this.
The study attains even more importance when the build-
ing under consideration has vertical geometric irregular-
ity. As, the behavior of such type of structure is not that
predictable or if even predicted that might be very ap-
proximate. So, an effective analysis is required such as
pushover analysis so as to study their response to the
earthquake event minutely. Pushover analysis is applica-
tion of gradually increasing lateral loads at every level of
the structure from bottom to the top story of the struc-
ture. The structure is subjected to the lateral loads until
the collapse and from there a pushover curve is obtained
which is then converted into capacity curve. This capac-
ity curve is merged with the demand curve which final-
ly gives the performance point of the structure. This is
an important insight to the buildings condition after an
earthquake that to what extent is the building damaged
or if it can be strengthened by retrofitting. The primary
objective of the pushover analysis was to identify the need
of retrofitting to the structure which has now been ex-
tended to the analysis of the existing building and it has
become a boon for the structural engineering to design
earthquake resistant buildings. Pushover analysis has
been the preferred method for seismic performance evalu-
ation of structures by the major rehabilitation guidelines
and codes because it is conceptually and computationally
simple. Pushover analysis allows tracing the sequence of
yielding and failure on member and structural level as
well as the progress of overall capacity curve of the struc-
ture.
Generally, global modifications to the structural system
are conceived such that the design demands, often denot-
ed by target displacement, on the existing structural com-
ponents, are less than their capacities. Lower demands
may reduce the risk of brittle failures in the structure and
avoid the interruption of its functionality. The present
work aims at assessment of seismic performance of the
RC framed structure with vertical geometric irregularities.
The structure is analyzed with and without inclusion of
cross steel bracing. The inelastic seismic response has
been quantified in terms of global performance param-
eters derived by means of non linear static analysis. The
steel bracing increases the lateral resisting capacity of
the structure and even in the base shear capacity of the
structure. Further, the steel bracings decrease the bend-
ing moments and shear forces in columns, they increase
the axial compression in the column to which they are
connected.
METHODS OF ANALYSIS
For seismic performance evaluation, a structural analysis
of the mathematical model of the structure is required
to determine force and displacement demands in various
components of the structure. Several analysis methods,
both elastic and inelastic, are available to predict the seis-
mic performance of the structures.
EQUIVALENT STATIC ANALYSIS
This approach defines a series of forces acting on a build-
ing to represent the effect of earthquake ground motion,
typically defined by a seismic design response spectrum.
It assumes that the building responds in its fundamental
mode. For this to be true, the building must be low-rise
and must not twist significantly when the ground moves.
The response is read from a design response spectrum,
given the natural frequency of the building (either calcu-
lated or defined by the building code). The applicability of
this method is extended in many building codes by ap-
plying factors to account for higher buildings with some
higher modes, and for low levels of twisting. To account
for effects due to "yielding" of the structure, many codes
apply modification factors that reduce the design forces
(e.g. force reduction factors).
RESPONSE SPECTRUM METHOD
Static procedures are appropriate when higher mode ef-
fects are not significant. This is generally true for short,
regular buildings. Therefore, for tall buildings, buildings
with torsional irregularities, or non-orthogonal systems,
a dynamic procedure is required. In the linear dynamic
procedure, the building is modelled as a multi-degree-of-
freedom (MDOF) system with a linear elastic stiffness ma-
trix and an equivalent viscous damping matrix.
NON LINEAR STATIC ANALYSIS
In general, linear procedures are applicable when the
structure is expected to remain nearly elastic for the level
of ground motion or when the design results in nearly
uniform distribution of nonlinear response throughout
the structure. As the performance objective of the struc-
ture implies greater inelastic demands, the uncertainty
with linear procedures increases to a point that requires
a high level of conservatism in demand assumptions and
acceptability criteria to avoid unintended performance.
Therefore, procedures incorporating inelastic analysis
can reduce the uncertainty and conservatism.
CAPACITY CURVE
The overall capacity of a structure depends on the strength
and deformation capacity of the individual components
of the structure . In order to determine capacity beyond
the elastic limits , some form of nonlinear analysis of the
structure is required.
A capacity curve is converted into capacity spectrum by
using a set of equation from ATC 40 which is known as
ADRS format. Initially the curve is obtained between base
shear and roof displacement which is converted into a
curve between Spectral acceleration and spectral dis-
placement, an example of capacity curve is shown in fig.
DEMAND CURVE
Ground motion during an earthquake produces complex
horizontal displacement patterns which may vary with
time. Tracking this motion at every time step to deter-
mine structural design requirement is judge impractical .
Demand curve is a representation of earthquake ground
motion .It is given by spectral acceleration vs time period

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International Journal of Research and Innovation (IJRI)
ADVANTAGES OF PUSHOVER ANALYSIS
The pushover analysis is an effective tool for the perfor-
mance evaluation of a structural system, by estimating
its strength and deformation demand induced during a
seismic event , by means of a static nonlinear analysis the
demands are then compared to available capacities at the
performance levels of interest. The evaluation is based on
assessment of important performance parameters such
as global drift, inter storey drift and inelastic element de-
formations .
NON LINEAR DYNAMIC ANALYSIS
Nonlinear dynamic analysis utilizes the combination of
ground motion records with a detailed structural model,
therefore is capable of producing results with relatively
low uncertainty. In nonlinear dynamic analyses, the de-
tailed structural model subjected to a ground-motion re-
cord produces estimates of component deformations for
each degree of freedom in the model and the modal re-
sponses are combined using schemes such as the square-
root-sum-of-squares.
TOOLS FOR PUSHOVER ANALYSIS
Many softwares are available on which pushover analysis
can be carried out, they are
• STAAD PRO
• ETABS
• SAP2000
• ADINA
• SC- PUSH3D
In this project the analysis is carried out using SAP2000
as it can provide most productive solution from a 2D frame
to a complex 3D model for nonlinear analysis. Advanced
analytical techniques provide step by step deformation;
Eigen and Ritz analyses based stiffness of nonlinear cas-
es. It is finite element software which works with complex
geometry. It also has by default all material properties
and codes like ATC 40, FEMA 356, FEMA 440, IS 1893
(part 1) : 2002 so as to facilitate easy and quick solution
for a set of boundary conditions.
PROCEDURE FOR PUSHOVER ANALYSIS
Pushover analysis can be performed as either force con-
trolled or displacement controlled depending on the phys-
ical nature of the load and the behavior expected from the
structure .Force controlled option is useful when the load
is known (such as gravity loading) and the structure is
expected to be used when specified drifts ar sought (such
as in seismic loading), where the magnitude of the ap-
plied load is not known in advance or where the structure
can be expected to lose strength or become unsuitable.
A displacement controlled pushover analysis is basically
composed of the following steps
VERTICAL IRREGULARITY
Due to the growing demands of aesthetic appearance of
the buildings engineers are bound to construct structures
with irregularities. Sometimes, due to the functionality of
the building the irregularities might have to be provided
i.e. for buildings which may have unusual purposes. How-
ever, it is undeniable that such type of irregularities in-
creases the vulnerability of the structures to earthquake
or any dynamic event. Torsion is one of the concerns that
might affect the building heavily in addition to that mass
and stiffness have considerable effect on the response of
the building. Geometrically as the structures reduces due
to the provision of setbacks, the stiffness of the structure
decreases and makes the structure more susceptible to
the large displacement which might turn quite cataclys-
mic. And even the mass of the building makes significant
contribution in the response of the building, if the mass of
the building is concentrated at certain portion then large
torsional moment will be developed which is again not
recommended for a structure. So as to overcome these de-
fects buildings of irregular configuration effective method
of analysis must be applied which is capable of detecting
the weak zones in the structures one of such analysis is
pushover analysis which is being carried out in the pro-
ject.
TYPES OF IRREGULARITIES
Structural irregularities are basically demarcated into
two categories:
i) Plan irregularity
ii) Vertical irregularity
Plan Irregularity (IS 1893 (Part 1): 2002)
a)Torsion Irregularity
To be considered when floor diaphragms are rigid in their
own plan in relation to the vertical structural elements
that resist lateral forces. Torsional irregularity is to be
considered to exist when the maximum storey drift, com-
puted with design eccentricity, at one end of the struc-
tures transverse to a axis is more than 1.2 times the aver-
age of the storey drifts at the two ends of the structure.
b)Re – entrant corners
Plan configuration of a structure and its lateral force re-
sisting system contain re-entrant corners, where both
projections of the structure beyond the re-entrant corner
are greater than 15 percent of its plan dimension in the
given direction.
c)Diaphragm Discontinuity
Diaphragm with abrupt discontinuities or variations in
stiffness, including those having cut-out or open areas
greater than 50 percent of the gross enclosed diaphragm
area, or changes in effective diaphragm stiffness of more
than 50 percent from one storey to the next.

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International Journal of Research and Innovation (IJRI)
d)Out of plane Offsets
Discontinuities in a lateral force resistance path, such as
out-of-plane offsets of vertical elements.
e)Non parallel Systems
The vertical elements resisting the lateral force are not
parallel to or symmetric about the major orthogonal axes
or the lateral force resisting elements.
Vertical Irregularities (IS 1893 (Part 1): 2002)
a)Stiffness Irregularity
A soft storey is one in which the lateral stiffness is less
than 70 percent of that in the storey above or less than 80
percent of the average lateral stiffness of the three storeys
above.
A extreme soft storey is one in which the lateral stiffness
is less than 60 percent of that in the storey above or less
than 70 percent of the average stiffness of the three sto-
reys above. For example buildings with STILTS will fall
under this category.
b)Mass Irregularity
Mass irregularity shall be considered to exist where the
seismic weight of any storey is more than 200 percent of
that of its adjacent storeys. The irregularity need not be
considered in case of roofs.
c)Vertical Geometrical Irregularity
Vertical geometrical irregularity shall be considered to ex-
ist where the horizontal dimension of the lateral force re-
sisting system in any storey is more than 150 percent of
that in its adjacent storey.
d)In-Plane Discontinuity in Vertical Elements resisting
Lateral Force
A in-plane offset of the lateral force resisting elements
greater than the length of those elements.
e)Discontinuity in Capacity – Weak Storey
A weak storey is one in which the storey lateral strength
is less than 80 percent of that in the storey above. The
storey lateral strength is the total strength of all seismic
force resisting elements sharing the storey shear in the
considered direction.
Following are the figures by which the irregularities in
structure are depicted such as mass irregularity, vertical
geometrical irregularity etc,.
Stiffness Irregularity
Mass Irregularity
Vertical Geometrical Irregularity
(A) (B)
(A) In-plane discontinuity in vertical lateral force-resisting ele-
ment
(B) Discontinuity in capacity (Weak storey)
DIFFERENT SEISMIC ZONES OF INDIA
The Indian subcontinent has a history of devastating
earthquakes. The major reason for the high frequency
and intensity of the earthquakes is that the Indian plate.
Geographical statistics of India show that almost 54% of
the land is vulnerable to earthquakes. A World Bank &
United Nations report shows estimates that around 200
million city dwellers in India will be exposed to storms
and earthquakes by 2050. The latest version of seismic
zoning map of India given in the earthquake resistant de-
sign code of India [IS 1893 (Part 1) 2002] assigns four

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levels of seismicity for India in terms of zone factors. In
other words, the earthquake zoning map of India divides
India into 4 seismic zones (Zone 2, 3, 4 and 5) unlike its
previous version which consisted of five or six zones for
the country. According to the present zoning map, Zone 5
expects the highest level of seismicity whereas Zone 2 is
associated with the lowest level of seismicity.
Center for Seismology, IMD under Ministry of Earth Sci-
ences is nodal agency of Government of India dealing
with various activities in the field of seismology and al-
lied disciplines. The major activities currently being pur-
sued by the Center for Seismology include, a) Earthquake
monitoring on 24X7 basis, including real time seismic
monitoring for early warning of tsunamis, b) Operation
and maintenance of national seismological network and
local networks c) Seismological data centre and informa-
tion services, d) Seismic hazard and risk related studies
e) Field studies for aftershock / swarm monitoring, site
response studies f) Earthquake processes and modeling,
etc. The IS code follows a dual design philosophy: (a) under
low probability or extreme earthquake events (MCE) the
structure damage should not result in total collapse, and
(b) under more frequently occurring earthquake events,
the structure should suffer only minor or moderate struc-
tural damage. The specifications given in the design code
(IS 1893: 2002) are not based on detailed assessment of
maximum ground acceleration in each zone using a de-
terministic or probabilistic approach. Instead, each zone
factor represents the effective period peak ground accel-
erations that may be generated during the maximum con-
sidered earthquake ground motion in that zone.
Zone 5
Zone 5 covers the areas with the highest risks zone that
suffers earthquakes of greater Intensity. The IS code as-
signs zone factor of 0.36 for Zone 5. Structural designers
use this factor for earthquake resistant design of struc-
tures in Zone 5. The zone factor of 0.36 is indicative of
effective (zero period) level earthquake in this zone. It
is referred to as the Very High Damage Risk Zone. The
region of Kashmir, the western and central Himalayas,
North Bihar, the North-East Indian region and the Rann
of Kutch fall in this zone.
Generally, the areas having trap rock or basaltic rock are
prone to earthquakes.
Zone 4
This zone is called the High Damage Risk Zone. The IS
code assigns zone factor of 0.24 for Zone 4. The Indo-
Gangetic basin and the capital of the country (Delhi),
Jammu and Kashmir fall in Zone 4. In Maharashtra, the
Faltan area (Koyananager) is also in zone no-4. In Bihar
the northern part of the state like- Raksaul, Near the bor-
der of India and Nepal, is also in zone no-4.
Zone 3
The Andaman and Nicobar Islands, parts of Kashmir,
Western Himalayas fall under this zone. This zone is clas-
sified as Moderate Damage Risk Zone and also 7.8 The IS
code assigns zone factor of 0.16 for Zone 3.
Zone 2
This region is liable to have less intensity and is classified
as the Low Damage Risk Zone. The IS code assigns zone
factor of 0.10 (maximum horizontal acceleration that can
be experienced by a structure in this zone is 10% of gravi-
tational acceleration) for Zone 2
PROCEDURE FOR PUSHOVER ANALYSIS IN SAP2000
SAP 2000 is a finite element software which is capable of
performing analysis for any type of structures in less time
. It gives a better result for non linear analysis . The pro-
cedure for the analysis consist of following steps :
i) Modeling
ii) Static Analysis
iii) Designing
iv) Pushover Analysis
Steps involved in SAP2000 to perform non linear static
analysis are,
• Creating the model in usual manner
• Defining the material properties for the analysis which
includes concrete, rebar and others, if necessary. All the
properties corresponding to a particular are by default
present in the software, the user has to just select those
details.
• Defining the frame properties like beam, column, slab
etc. in the similar way by making appropriate selections.
• Define properties and acceptance criteria for the pusho-
ver hinges. The program includes several built-in default
hinge properties that are based on average values from
FEMA-356 for concrete members. These built in proper-
ties can be useful for preliminary analyses, but generally
user defined properties are recommended.
• Assigning loads for respective member and hinges to
beams and columns of bending axial type respectively on
both ends of members.
• Define the pushover case, more than one pushover anal-
ysis can also be defined in one analysis.
• Run the basic analysis till the gravity loads and the
members of the structure must be safe under these loads
and then the pushover case.
• Display pushover curve and table which is the structure
response plotted between spectral acceleration and spec-
tral displacement.

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International Journal of Research and Innovation (IJRI)
BARE FRAME RESULTS AND DISCUSSION
GENERAL:
All models under the study has be analyzed using pusho-
ver analysis which is often referred as non linear static
analysis in various zones of India. The models have been
subjected to the loads as per codal provisions and the
results as discussed earlier are analyzed in terms of base
shear, roof displacement etc,. Shear capacity of the build-
ing has been enhanced by using steel bracings. perfor-
mance of each building are obtained through this proce-
dure.
RESULTS:
Pushover curves for Zone II and Zone III (Bare Frame)
Push over curves for Zone III and Zone IV(Bare Frame)
Pushover curves for Zone II and Zone III (X steel Bracing)

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International Journal of Research and Innovation (IJRI)
Pushover curve for Zone IV and Zone V (Steel bracing)
COMPARISION OF PUSHOVER CURVES
Pushover curves for different zones (Bare Frame)
Pushover curves for different zone (X Steel Bracing)
From the above plot we conclude that base shear devel-
oped in the structure for zone V is more and it decreases
from Zone V to Zone II as the intensity of earthquake is
more in Zone V and it decreases from Zone V to Zone II.
Comparison of Pushover curve for Bare Frame and X
Steel Bracing
Comparison of Pushover curve for Bare Frame and X Steel
Bracing(Zone II)
Comparison of Pushover curve for Bare Frame and X Steel
Bracing(Zone III)
Comparison of Pushover curve for Bare Frame and X Steel
Bracing(Zone IV)
Comparison of Pushover curve for Bare Frame and X Steel
Bracing(Zone IV)
From the above figures it is evident that the performance
of the structure is enhanced when lateral systems (x steel
bracings) are included for a structure. As from the figure
the structure with steel bracing is able to withstand more
lateral loads thereby increasing the base shear capacity
of the structure and increment of the base shear is quite
considerable in all the zones
Drift:
As discussed earlier that the drift of the structure is the
difference of the displacement of successive stories. . Ac-
cording to IS 1893 (part1): 2002 the story drift for any
level should not be greater than 0.004H.

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International Journal of Research and Innovation (IJRI)
BARE FRAME STRUCTURE PERFORMANCE POINT
Performance point can be obtained by capacity spectrum
and demand spectrum and the intersection point of these
two curve is performance point.
Performance point for G+15 storied Bare Frame building(Zone II)
Table: Resultant Base Shear vs Roof Displacement
Above tabulated format is for the G+15 storied Bare Frame
building in Zone 2 which lies in IO to LS performance level
Performance point for G+15 storied Bare Frame building(Zone III)
Table: Resultant Base Shear vs Roof Displacement
Above tabulated format is for the G+15 storied Bare Frame
building in Zone 3 which lies in IO to LS performance level

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International Journal of Research and Innovation (IJRI)
CONCLUSIONS
• we conclude that base shear developed in the structure
for zone V is more and it decreases from Zone V to Zone
II as the intensity of earthquake is more in Zone V and it
decreases from Zone V to Zone II.
• performance of the structure is enhanced when lateral
systems (x steel bracings) are included for a structure.
• Due to the provision of setback there is significant
change at the level of setback which causes uneven dis-
tribution of forces as the structure is Geometrically verti-
cal irregular.
• considerable decrease in the value of Drift in various
zones by the provision of X Steel bracing (lateral support)
in the structure.
• It is also notable that the drift ratio % for all the struc-
tures under consideration changes abruptly at the level
of setback.
• Base shear of the Bare Frame is less then that of struc-
ture with X Steel Bracing (lateral support) as the struc-
ture is capable of observing more lateral forces when X
Steel Bracings are provided.
• In Zone V it is observed that structure can be collapsed
even after the provision of X Steel Bracing due to high
intensity of Earthquake
• Performance level of the structure is observed to in-
crease considerably when Lateral support is provider in
the structure.
REFERENCES
IS 1893-2002(Part 1), “Criteria for Earthquake Resistant
Design of Structures” , Bureau of Indian Standards.
• ATC 40, “Seismic Evaluation and Retrofit of Concrete
Buildings” , California Seismic Safety Commission.
• FEMA 356, “NEHRP Guidelines for the Seismic Rehabili-
tation of Buildings ” ,American society of civil engineers,
Washington, D.C.
• Federal Emergency Management Agency (FEMA 273)
NEHRP GUIDLINES (1997) developed a set of technically
sound, nationally applicable guidelines (with commen-
tary) for the seismic rehabilitation of buildings, Washing-
ton DC, U.S.A.
• IS 456 : 2000 “Plain and Reinforced Concrete Code of
Practice” , Bureau of Indian Standards
Author
Mohammed Azemuddin
Research Scholar,
Department of Civil Engineering, Aurora S Scientific and
Technological and Research Academy, Bandlaguda,
Hyderbad India.
Mythili Rao,
Assistant Professor,
Department of Civil Engineering,
Aurora's Scientific Technological and Research Academy,
Hyderabad India.
Mohammed Abdul Hafeez
Associate professor,
Department Of Civil Engineering,
Maulana Azad National Urdu University,
Hyderabad India.