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International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 4, April 2017, pp. 689–702 Article ID: IJCIET_08_04_080
Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=4
ISSN Print: 0976-6308 and ISSN Online: 0976-6316
© IAEME Publication Scopus Indexed
SEISMIC ANALYSIS ON MEZZANINE
FLOORING SYSTEM
S. Loganantham
PG Student, Division of Structural Engineering,
School of Mechanical and Building Sciences,
VIT University, Chennai – 600127, India
Dr. M. Shanmugasundaram
Asst. Professor (SG), Division of Structural Engineering,
School of Mechanical and Building Sciences,
VIT University, Chennai – 600127, India
ABSTRACT
In this study the seismic performance of mezzanine flooring system is compared to
various storey heights of the structure. For this purpose, seven storey structure was
modelled using E-tabs. In this study three type model was taken they were regular
structure, irregular structure and irregular structure on sloppy ground. In this three
model mezzanine floors are located first at half storey height of the structure and then
mezzanine floors are located at three-fourth height of the structure and its assumed that
the building were located in the seismic zone V. In this study linear dynamic and
nonlinear dynamic analysis is carried out using E-tabs. This method is used to study
the response of the building under seismic loadings in terms of storey displacement,
storey drift and as well as response spectrum analysis, time history analysis. The
response for each type of building are studied and compared. Introducing mezzanine
floors in the structure, its creates short column effects so this study also concentrated
on how to overcome the short column effect economically.
Key words: Mezzanine Flooring; Response Spectrum; Short Column Effects; Time
History Analysis
Cite this Article: S. Loganantham and Dr. M. Shanmugasundaram, Seismic Analysis
On Mezzanine Flooring System. International Journal of Civil Engineering and
Technology, 8(4), 2017, pp. 689–702.
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Seismic Analysis On Mezzanine Flooring System
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1. INTRODUCTION
The primary concern of structural engineer is protected structure from seismic forces and
design will be economical. Generally seismic analysis of structure is used to understand the
structural behavior. Seismic loads are different from normal loads like wind and gravity loads.
Based on this type load analysis, we will expect damage level of structure and we will redesign
before construction stage [15].
Mezzanine floors are like temporary floors it is used to increase a space of existing areas.
It can be easily removable and reusable. This type of mezzanine floors is used in industrial
purpose, educational institute and storage yards. It also called semi-percent structure, it’s
generally placed in the half of the storey height of the building. It’s didn't consider as a floor of
the building, its normally consider as a temporary structure of the building. Based on the
international codes mezzanine to have as much as one-third of the floor space compare to floor
below. This type of mezzanine floors is used in modern architecture. In industrial mezzanine
floors are used for storage purpose in industrial mezzanine floors are free standing using steel
columns and joist it can be easily removable and relocatable. But no one defining the perfect
height to locate mezzanine in storey of the building [11]. For Mezzanine floorings slabs and
beams are made of fiber reinforced aerated light weight concrete (FALC). This type of concrete
is made for improving thermal conductivity, fire resistance and energy absorption. In this study,
about carbon and polypropylene fibers were investigated0 to 4 percentage volume ratio and
self-compacting agent also used for reducing the water cement ratio. In this study, they
investigated based on uni-axial compression test, modulus of elasticity and toughness index. In
this research, 4 percent of polypropylene fiber aerated concrete gives better result compared to
carbon fiber based on this Mezzanine floor and beams are considered polypropylene fiber
reinforced aerated concrete [19]. In seismic force all of the structural components act similar
in regular structure, but in irregular structure, each and every component act differently but in
real-time structures are irregular type only. So a study of irregular structure is very important.
Irregularity is classified based on two classifications
In this project we took vertical and horizontal irregularity. In vertical irregularity, we have
taken Mass, stiffness and strength irregularity and in horizontal irregularity Asymmetrical plan
shape irregularity are taken [17]. Mass irregularity means if the mass of the any storey is more
than 150 percentage of the any adjacent storey it’s called mass irregularity, but in this type of
irregularity isn't affecting structure safety that much [13]. Stiffness irregularity means when the
lateral stiffness of the storey is less than 70 percentage of the stiffness any adjacent storey or
80 percentage of average stiffness of three storeys above or below in the structure. Strength
irregularity means the shear strength of the building is less than 90percentage that in the storey
above. For strength and stiffness irregularity creates storey displacement and storey drift due
to seismic loads [18]. So we want to take consider seismic storey displacement and storey drifts.
Storey displacement is the total displacement of its storey of with respect to the ground for high
rise buildings (H/350) and for low rise building (H/250) in here H is total height of the building.
Storey drift is the ratio of displacement of two consecutive floors in height of the floor. This
type of irregularities creates severe damage in structure so we want to give importance to this
type irregularity for generally irregular structures and structure located in high seismic zones
are tested by dynamic analysis. Dynamic analysis is classified in two types they are linear
dynamic and Non-linear dynamic analysis. In linear dynamic response spectrum analysis are
carried out and for Non-linear dynamic Time History analysis are carried out. In response
spectrum analysis, seismic response of structures based on range of periods is shown in a single
graph. For an earth quake motion and percentage of critical damping response spectrum plot
given earthquake response related to acceleration, displacement for a complete range of
building period. For Time History analysis specified loadings and specified time periods are
S. Loganantham and Dr. M. Shanmugasundaram
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given directly and it shows the response of the building. In this research response spectrum
analysis is compared to time history analysis. [12] Due to the introduction of mezzanine floors
at existing structure is create a short column effect. Short columns create severe damage due to
seismic force. Short column is stiffer than long column, so it attracts large seismic forces [10].
To rectify this type of effect we want to give shear reinforcement, but it increases the required
reinforcement of the building so we want to find an economical solution for this problem.
2. OBJECTIVE
• To find the effect of Mezzanine floors in structure under seismic loadings
• To design an economical mezzanine floor incubated in structures in the high seismic
zone for regular and irregular structures.
• To overcome the short column effects due to introducing mezzanine in structures
without increase shear reinforcement.
• To find better height of Mezzanine floor to locate in storey height.
• Dynamic analysis of mezzanine floors incubated structures using response
spectrum and time history analysis.
3. STRUCTURAL MODELLING AND ANALYSIS
3.1. General
The structural analysis and design of the building software E-tabs 2016 is used to design a
model based on this software we can analysis linear and Non-linear analysis. This software is
used to predict the geometrical linear and Non-linear behavior of structure under static and
dynamic loadings taking into account Non-linearity and material inelasticity. This software
accepts static (either force or displacement) and dynamic (acceleration) action.
3.2. Detail of Model
The models which have been adopted for the study are three types
• A regular structure
• Irregular structure
• Irregular structure at sloppy ground
Each structure is seven storey (G+6). The building is considered rectangular column
(450X300 mm) and square beam (300X300mm). The floor slabs are taken as 125mm thickness
and for Mezzanine floor beams are (230X230mm) and floor slabs are taken as 100mm thickness
and type of concrete is fiber aerated polymer reinforced concrete and for normal structure M30
and Fe415 steel and each storey are 3meter height for Mezzanine first located at half of the
storey height and another one is three-fourth of the storey height of the building and shear walls
are used for lift pit thickness of 230mm. A structure located in high seismic zones (V- zone).
Loads are given based on IS codes like Live load and floor finish loads are taken from IS 875-
part 2 and wind load is taken from IS 875-part-3. Seismic loadings are taken from IS 1893-part
1 and Dead load directly calculated from E-tabs. In E-tabs all code books are already in build
so we want to assign codes based on type of loads. A response reduction factor taken has 3
because of general building based on IS 1893-part 1 and Importance factor taken has 1.5 for
R.C buildings based on IS 1893-part 1. Zone factor is 0.36 for zone 5 as per IS 1893-part 1.
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3.3. 2D AND 3D PLAN OF
Figure 1 Regular structure Figure 2 Irregular structure
Fig 3 Section view of Irregular on structure on sloppy ground Fig 4 Plan view of irregular structure on sloppy ground
Figure 5 Mezzanine at half and three-fourth height of the regular structure
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Figure 6 Mezzanine at half and three-fourth height of the irregular structure
Figure 7 Mezzanine at half and three-fourth height of the irregular structure on sloppy ground
4. RESULTS AND DISCUSSION
Dynamic analysis of three types of structure carried out. Due to introducing of Mezzanine
floors its creates Mass, strength and stiffness irregularity so we want to consider storey
displacement and storey drift results in both X and Y directions. Response spectrum analysis
and Time history analysis results also compared. Introducing of mezzanine its create short
column, so we want to take shear force and bending moment of the column. In this results
structure is mentioned in two types. They are type 1 is a mezzanine at half storey height of
structure and type 2 is mezzanine at three-foot height of the structure.
4.1. REGULLAR STUCTURE
Figure 8 Displacement of Mezzanine at half and three-fourth height of the regular structure in X and
Y-Direction
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Above fig8 shows the displacement results of mezzanine at half and three-half storey height
of the building. In this result shows displacement in X and Y Direction of mezzanine at three-
fourth is less than the displacement of mezzanine at half storey height of the structure.
Figure 9 Drift of Mezzanine at half and three-fourth height of the regular structure in X and Y –
Direction
Above fig9 shows the drift results of mezzanine at half and three-half storey height of the
building. In this result shows drift in X and Y Direction of mezzanine at three-fourth is less
than the drift of the mezzanine at half storey height of the structure.
Figure 10 Response spectrum analysis of Mezzanine at half and three-fourth height of the regular
structure
Table 1 Maximum and minimum acceleration of mezzanine at half and three-fourth storey height
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From table1. Maximum acceleration of mezzanine at three-fourth is less than mezzanine at
half storey height. Based on this mezzanine with three-fourth storey height is safer than
mezzanine at half storey height
Figure 11 Time history analysis of Mezzanine at half and three-fourth height of the regular structure
Table 2 Maximum and minimum acceleration of mezzanine at half and three-fourth storey height
From table2. Maximum acceleration of mezzanine at three-fourth is less than mezzanine at
half storey height. Based on this mezzanine with three-fourth storey height is safer than
mezzanine at half storey height.
4.2. IRREGULLAR STUCTURE
Figure 12 Displacement of Mezzanine at half and three-fourth height of the irregular structure in X
and Y-Direction
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Above fig12 shows the displacement results of mezzanine at half and three-half storey
height of the building. In this result shows displacement in X and Y Direction of mezzanine at
three-fourth is less than the displacement of mezzanine at half storey height of the structure.
Figure 13 Drift of Mezzanine at half and three-fourth height of the irregular structure in X and Y –
Direction
Above fig13 shows the drift results of mezzanine at half and three-half storey height of the
building. In this result shows drift in X and Y Direction of mezzanine at three-fourth is less
than the drift of the mezzanine at half storey height of the structure.
Figure 14 Response spectrum analysis of Mezzanine at half and three-fourth height of the regular
structure
Table 3 Maximum and minimum acceleration of mezzanine at half and three-fourth storey height
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From table3. Maximum acceleration of mezzanine at three-fourth is less than mezzanine at
half storey height. Based on this mezzanine on three-fourth storey height is safer than
mezzanine at half storey height.
Figure 15 Time history analysis of Mezzanine at half and three-fourth height of the regular structure
Table 4 Maximum and minimum acceleration of mezzanine at half and three-fourth storey height
From table4. Maximum acceleration of mezzanine at three-fourth is less than mezzanine at
half storey height. Based on this mezzanine on three-fourth storey height is safer than
mezzanine at half storey height.
4.3. Irregullar Stucture on Sloppy Ground
Below fig16 shows the displacement results of mezzanine at half and three-half storey height
of the building. In this result shows displacement in X and Y Direction of mezzanine at three-
fourth is less than the displacement of mezzanine at half storey height of the structure.
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Figure 16 Displacement of Mezzanine at half and three-fourth height of the irregular structure on
sloppy ground in X and Y-Direction
Figure 17 Drift of Mezzanine at half and three-fourth height of the irregular structure of sloppy
ground in X and Y –Direction
Above fig17 shows the drift results of mezzanine at half and three-half storey height of the
building. In this result shows drift in X and Y Direction of mezzanine at three-fourth is less
than the drift of the mezzanine at half storey height of the structure.
From table5. Maximum acceleration of mezzanine at three-fourth is less than mezzanine at
half storey height. Based on this mezzanine on three-fourth storey height is safer than
mezzanine at half storey height.
Figure 18 Response spectrum analysis of Mezzanine at half and three-fourth height of the regular
structure on sloppy ground
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Table 5 Maximum and minimum acceleration of mezzanine at half and three-fourth storey height
Figure 19 Time history analysis of Mezzanine at half and three-fourth height of the regular structure
on sloppy ground
Table 6 Maximum and minimum acceleration of mezzanine at half and three-fourth storey height
From table6. Maximum acceleration of mezzanine at three-fourth is less than mezzanine at
half storey height. Based on this mezzanine on three-fourth storey height is safer than
mezzanine at half storey height
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Due to introducing of Mezzanine floors in existing structures so its create short
column effects. So based on this critical section of structure is taken and its bending
moment and shear forces are compared.
Table 7 Maximum and minimum bending moment and shear force for regular structure
Table 8 Maximum and minimum bending moment and shear force for irregular structure
Table 9 Maximum and minimum bending moment and shear force for irregular structure on sloppy
ground
Based on the critical section bending moment and shear force mezzanine at three-fourth is
create less than compared to mezzanine at half storey height
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5. CONCLUSION
From the above results it can be can be concluded
1. Based on storey displacement and storey drift mezzanine at three-fourth height is less than
mezzanine at half of the storey height so if mezzanine at three-fourth is safer in regular and
irregular structure
2. Based on response spectrum analysis and Time history analysis maximum acceleration for thee-
fourth height of mezzanine is less than half storey height of mezzanine. So three-fourth
mezzanine is safer than mezzanine at half storey height.
3. Based on bending moment and shear force in critical section mezzanine at three-fourth gives
less value compared to mezzanine at half of the storey height. So we can reduce the shear force
and bending moment without increasing a shear reinforcement.
4. Due to introducing mezzanine its create mass, stiffness and strength irregularity. Based on this
storey displacement and storey drift result show structure is safe in both mezzanines at half and
three-fourth height of the structure, but mezzanine at three-fourth gives better results than
mezzanine at half of the storey height.
5. Mezzanine at three-fourth height gives better results without increasing shear reinforcement so
we don’t need to give additional reinforcement. So it's economically better than introducing
shear reinforcement methods.
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