Post on 24-Mar-2020
© September 2019 | IJIRT | Volume 6 Issue 4 | ISSN: 2349-6002
IJIRT 148642 INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 179
Design and Analysis of Residential Building
Faisal Mehraj Wani1, Tamseel Ahmad Bhat
2, Khair Ul Faisal Wani
3, Danish Zahoor
4
1,3M.Tech. Student, Structural Engineering, Jain University, Bengaluru
2,4B.Tech. Student, Civil Engineering, Jain University
Abstract- Manual design of multistory building is
becoming obsolete day by day due to invent of new
software’s like ETABS, STAAD PRO. This software
save energy, time, provide exact and provide precise
results. Etabs offer a single user interface to perform:
Modeling, Analysis, Design and Detailing. We have
adopted limit state method of analysis. The design is in
confirmation with IS 456-2000.
In this project we are analyzing (G+3) residential 2
BHK flat by using Etabs. —ETABS stands for
Extended Three dimensional Analysis of Building
Systems. The modeling of structure is done in rivet and
a realistic 3d image of structure is obtained. Design of
beam, column is done by Etabs. Staad foundation is
used for designing of footing and spread sheet for
designing of slabs. Post analysis of the structure,
maximum shear forces, bending moments, and
maximum storey displacement are computed.
Index terms- Boiler Etabs, Staad foundation
1. INTRODUCTION
Structural design is the primary aspect of civil
engineering. Structural analysis means determination
of the general shape and all the specific dimensions
of a particular structure so that it will perform the
function for which it is created and will safely
withstand the influences which will act on it
throughout its useful life. The foremost basic in
structure is the design of simple basic components
and members of a building like slabs, beams,
columns, and footings. In order to design them it is
important to first obtain the plan of the particular
building. Thereby depending on the suitability plan
layout of beams and the position of columns are
fixed. Thereafter, the vertical loads are calculated
namely the dead load and live load. Once the loads
are obtained, the component takes the load first i.e.
the slabs can be designed. Designing of slabs depends
upon whether it is a one-way or a two-way slab, the
end condition and the loading. From the slabs, the
loads are transferred to the beam. The loads coming
from the slabs onto the beam may be trapezoidal or
triangular. Depending on this, the beam may be
designed. Thereafter, the loads (mainly shear) from
the beams are taken by the columns. For designing
columns, it is necessary to know the moments they
are subjected to for this purpose; frame analysis is
done by Kanis method. After this the designing of
column is taken up depending on end conditions,
moments, eccentricity and if it is a short or slender
column. Finally, the footings are designed based on
the loading from the column and also the soil bearing
capacity value for that` particular area. Most
importantly, the sections must be checked for all the
components with regard to strength and
serviceability.
1.1 OBJECTIVE
Following are the objectives
1. Modeling the building using the software
ETABS 2016
2. Applying gravity loads and different load
combinations as per Indian codal provision.
3. Analyzing and designing of residential building
for worst case of load combination.
4. Design of footing using STAAD foundation.
1.2 PLAN OF RESIDENTIAL BUILDING
The residential building 2bhk flat is taken for
analyzing and designing. The architect plan was
modeled in Revit and a realistic 3d image of structure
is obtained. Placements of column were done keeping
in mind the orientation and the distance between the
columns. After placement of column the beams were
run parallel to columns to form structure layout.
© September 2019 | IJIRT | Volume 6 Issue 4 | ISSN: 2349-6002
IJIRT 148642 INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 180
Fig 1.1 Plan of residential building
Fig 1.2 3D of residential building using Revit
software
2. MODELLING OF RCC FRAMES
An RCC framed structure is basically an assembly of
slabs, beams, columns and foundation inter-
connected to each other as a unit. The load transfer
mechanism in these structures is from slabs to beams,
from beams to columns, and then ultimately from
columns to the foundation, which in turn passes the
load to the soil. In this structural analysis study, we
have adopted a regular geometry with dimension
11.09x12.25M. A floor to floor height of 3m is
assumed. Structural Plan of the building is shown in
the following figure.
Fig 2.1 Structure layout of residential building
Table 1 Building Description
Length x Width 12.25x11.09m
No. of storeys 4
Height of similar storey 3m
Height of parapet wall 1m
Thickness of outer wall 230mm
Thickness of inner wall 125mm
Beam dimension 230x450mm
Column dimension 250x450mm
Table 2 material specification
Grade of concrete,M25 fck= 25N/mm2
Grade of steel fy= 415N/mm2
Density of brick ϒbrick= 20kN/m
Density of concrete ϒc= 25kN/m
2.1 LOADING
Loads acting on the structure are dead load (DL),
Live load and Earthquake load (EL).
1. Dead load: Wall load, Parapet load and floor load
(IS 875(Part1))
The dimensions of the cross section are to be
assumed initially which enable to estimate the dead
load from the known weights of the structure. The
values of the unit weights of the structure and the
values of the unit weight of the materials are
specified in IS 875:1987(Part-I). As per IS 875: 1987
© September 2019 | IJIRT | Volume 6 Issue 4 | ISSN: 2349-6002
IJIRT 148642 INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 181
(part I). The dead load assigned in the ground floor is
shown in the figure 3.
Unit weight of brick = 20 kN/m 3
Unit weight of concrete = 25kN/m
a) Wall load= (unit weight of brick masonry X wall
thickness X wall height)
= 20 kN/m3 X 0.230m X (3-0.45) m = 11.73
kN/m (acting on outer beam)
= 20 kN/m3 X 0.125m X (3-0.45) m = 6.375
kN/m (acting on inner beam)
b) Wall load (due to Parapet wall at top floor) =
(unit weight of brick masonry X parapet wall
thickness X wall height) = 20 kN/m3 X 0.125m
X 1m= 2.5 kN/m
Fig 2.1 Details of wall load on frames
2. Live load:
They are also known as imposed loads and consist of
all loads other than the dead loads of the structure.
The standard values are stipulated in IS875:1987
(part II).The live loads considered are given in table.
The assigned live load on ground floor in Etabs will
be as shown in the figure. Live load: 2kN/m2 (acting
on slab)
Table 3 live loads (IS875:1987 (part II)
Area Live load ( kN/m2 )
All rooms and kitchens 2
Toilet and bathrooms 2
Corridors, Passages,
Staircases
3
Balconies 3
Parking 5
Electrical Room 5
Machine room 5
Fig 2.2 Details of live load on shells
3. Floor finish: 1 kN/m
Fig 2.3 Details of floor finish on shells
4. Seismic Load:
Earthquakes generate waves which move from the
origin of its location with velocities depending on the
© September 2019 | IJIRT | Volume 6 Issue 4 | ISSN: 2349-6002
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intensity and magnitude of the earthquake. The
impact of earthquake on the structures depends on the
stiffness of the structure, stiffness of the soil media,
height and location of the structure, etc. the
earthquake forces are prescribed in IS 1893:2002
(part-I).
Seismic zone: V (Z=0.36), Soil type: I, Importance
factor: 1, Response reduction factor: 5, Damping:
5%. IS 1893(Part-1):2002
Here Seismic load is considered along two directions
EQlength and EQwidth.
2.2 LOAD COMBINATION
The structure should be analyzed for different load
combination as different types of loads are acting on
a structure throughout the life of structure. The
different types of loads on the building are
1. Dead load
2. Live load
3. Eq X
4. EQ Y
The beams, column and slab are designed for
factored load combination whereas footings are to be
designed for factored load combination. Geotechnical
engineer has already taken factor of safety into
account while determining the safe bearing capacity
(SBC) of soil.
3. ANALYSIS
Fig 3.1 Displacement of joints
It can be seen that the displacement increase while
going up as the fixity of column decreases as we go
up as there is no floor on the top. The displacement at
top floor is minimum.
Fig 3.2 Bending moment diagram
Colorful image of bending moment is obtained from
software. The BM at the ends are hogging which
means reinforcement is to be provided at the top
while in the middle portion BM is sagging, the
reinforcement provided at bottom. The BM at the
Centre is maximum as we go up due to decreases in
fixity of joints.
Fig 3.3 Axial force diagram
© September 2019 | IJIRT | Volume 6 Issue 4 | ISSN: 2349-6002
IJIRT 148642 INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 183
Fig 3.4 Details of axial force due to seismic load
The axial force for the bottom stories is more than the
top stories. Structures experiencing earthquake
forces, axial force for external column is high while
internal column experience less force as shown in
above figure.
4. CONCRETE FRAME DESIGN
The design methods used for the design of reinforced
concrete structures are working stress method,
ultimate load method and limit state method. Here we
have adopted the limit state method of design for
slabs, beams, columns and stairs. In the limit state
method, the structure is designed to withstand safely
all loads liable to act on it through its life and also to
satisfy the serviceability requirements, such as
limitation to deflection and cracking. After the
analysis and interpretation of result, the concrete
frame design is carried out by selecting the design
load combination. The structural member (column
and beam) is said to be failed if it is shown in red
color. The minimum reinforcement of columns
should be 0.8% of cross section and maximum should
be 6% of cross section but practically 4% of cross
section is taken into consideration. The minimum
reinforcement in beams should be 0.4bd and
maximum of 4% of cross section. All the structural
members passed the design check in this project as
shown in figure.
Fig 4.1 concrete frame design
Fig 4.2 check for concrete frame design
5. DETAILING
The final step after designing is to generate rebar
tables for structural members. The detailing process
helps us to generate drawing sheets, floor plans,
reinforcement cage view etc.
© September 2019 | IJIRT | Volume 6 Issue 4 | ISSN: 2349-6002
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Table 4 concrete beam rebar table
6. DESIGN OF SLAB
The slabs were designed using spread sheet in which
length and width were used to check the minimum
required thickness and reinforcement of slab. The
minimum thickness was takes as 125mm for whole
structure. The minimum steel for slab should be
0.12%of c/s area of slab.
Fig 6.1 Spread sheet for designing of slab
7. DESIGN OF FOUNDATION
The footings were designed using staad foundation.
The FZ forces were imported to staad foundation to
design all footing at once. The footing should be
designed as isolated in the beginning; if the footings
are overlapping then we should design for combined
footing. The SBC of soil was taken as 150kpa and the
depth of soil above footing as 2000mm.In this project
we are designing isolated footing as the exaction plan
does not coincide. The different sizes of footing were
obtained from the software.
Fig 7.1 Excavation plan for residential building
Table 5 Details of size of footing
8. CONCLUSION
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1. This project has given an opportunity to re-
collect and co-ordinate the various methods of
designing and engineering principles which we
have learnt in our lower classes.
2. Analysis was done by using ETABS software
and successfully verified manually as per IS456.
3. Calculation by both manual work as well as
software analysis gives almost same result.
4. Shear force and bending moment increases for
both beams and columns as the storey height
Increases.
5. Design of isolated footing was done
successfully.
REFERENCES
[1] IS: 456-2000, Code of Practice Plain and
Reinforced Concrete.
[2] IS: 875-1987 (Part 1) – 1987, Code of practice
for design loads (other than earthquake) for
buildings and structures.
[3] IS: 875-1987 (Part 1) – 1987, Code of practice
for design loads (other than earthquake) for
buildings and structures – Imposed loads.
[4] Mohd atif et [al] “comparative study on seismic
analysis of multistory building stiffened with
bracing and shear wall”, IRJET – 2015.
[5] Syed khasim mutwallie et [al] “Dynamic
response of high rise structure under the
influence of shear walls”. Int. Journal of
engineering research and applications. ISSN:
22248-9622, vol 4.