RESIDENTIAL BUILDING

Urlabari, Morang

STRUCTURE ANALYSIS
AND DESIGN REPORT
MAIN REPORT AND ANNEX

Submitted By Submitted To:

Urlabari, Morang

November 2024
STRUCTURAL ANALYSIS REPORT

Table of Contents

1. Project Details.......................................................................................8

1.1 Building Design Parameters....................................................................10

1.2 Materials..............................................................................................10

1.2.1 Concrete............................................................................................ 10

1.2.2 Reinforcement Steel..........................................................................10

1.3 Load calculations.................................................................................11

1.3.1 Dead Load......................................................................................... 11

1.3.2 Superimposed Dead Loads................................................................11

1.3.3 Live Loads.......................................................................................... 11

1.3.4 Floor Finish Loads..............................................................................12

1.3.5 Seismic Loads.................................................................................... 12

1.4 Load Combination...............................................................................14

2. Structural Analysis and Design of Main Building.................................15

2.1 Preliminary Sizing.................................................................................... 15

2.1.1 Slab.................................................................................................... 16

2.1.2 Beam................................................................................................. 16

2.1.3 Column.............................................................................................. 16

2.2 3D modelling of the building...................................................................17

2.3 Load Applied on Building:........................................................................20

2.4 Analysis Result: ...................................................................................... 25

2.4.1 Auto Seismic Load Definitions...........................................................27

2.4.2 Modal Analysis................................................................................... 29

2.4.3 Displacement and drift of the building...............................................29

2.4.4 Irregularity Check.............................................................................. 32

2.4.4 Force/Stresses Diagrams...................................................................34

School Building PAGE |

2
STRUCTURAL ANALYSIS REPORT

2.5 Design of element:.................................................................................. 37

2.5.1 Design of footing............................................................................... 38

2.5.2 Design of Column.............................................................................. 41

2.5.3 Design of Beam................................................................................. 47

2.5.4 Design of Slab.................................................................................... 55

2.5.5 Design of Staircase............................................................................59

3 Conclusions and Recommendations....................................................64

List of Figures

Figure 1-1: Ground Floor Plan................................................................................ 8

Figure 2-1: 3D Model of Building..........................................................................17

Figure 2-2: Plan of the building............................................................................18

Figure 2-3: Elevation of the building....................................................................19

Figure 2-4: Wall load on beam.............................................................................21

Figure 2-5: Live load applied on floor..................................................................22

Figure 2-6: Floor Finish load on floor....................................................................23

Figure 2-7: A dead load of steps on waist slab....................................................24

Figure 2-8: Diaphragm Extent.............................................................................. 24

Figure 2-9: Deformed shape under dead load and mode 1..................................25

Figure 2-10: Deformed shape under modal load case (Mode 2 and 3)................26

Figure 2-11: Base shear distribution along X and Y.............................................28

Figure 2-12: Story drift along X and Y direction...................................................30

Figure 2-13: Story displacement along X and Y direction....................................31

Figure 2-14: Axial Force Diagram........................................................................34

Figure 2-15: Shear Force Diagram.......................................................................35

School Building PAGE |

3
STRUCTURAL ANALYSIS REPORT

Figure 2-16: Bending Moment Diagram...............................................................36

Figure 2-17: Model Check.................................................................................... 37

Figure 2-18: Base Reactions from ETABS.............................................................38

Figure 2-19: Design reinforcement detail (Elevation view)..................................41

Figure 2-20: Design reinforcement detail (Elevation view)..................................42

Figure 2-21: Design reinforcement detail (Elevation view)..................................42

Figure 2-22: Design shear reinforcement details (Plan view)..............................48

Figure 2-23: Design reinforcement details (Plan view)........................................49

Figure 2-24: Bending moment diagram (1.5DL + 1.5LL combination).................54

Figure 2-25: Force diagram for critical beam.......................................................54

List of Table

Table 1.4-1: Mass Source..................................................................................... 15

Table 2-1: Section property and modifiers...........................................................17

School Building PAGE |

4
STRUCTURAL ANALYSIS REPORT

Table 2-2: Wall load calculation...........................................................................21

Table 2-3: Live load intensity...............................................................................22

Table 2-4: Floor Finish Load Calculation..............................................................23

Table 2-5: Auto Seismic Load Data......................................................................27

Table 2-6: Lateral load in stories.........................................................................27

Table 2-7: Modal Participating Mass Ratios..........................................................29

Table 2-8: Centers of Mass and Rigidity...............................................................29

Table 2-9: Check for Drift

Table 2-10: Check for Mass Irregularity

Table 2-11:Check for Stiffness Irregularity

Table 2-12:Check for Torsion

Symbols and Abbreviation

acr Distance from the point considered to the surface of nearest
longitudinal bar
Asc Area of compression reinforcement
Ast Area of tension reinforcement
b Breadth of member

School Building PAGE |

5
STRUCTURAL ANALYSIS REPORT

b1 Breadth of section enclosed within main reinforcement

Bc Ratio of short side to long side
BM Bending Moment
d Effective depth of member
D Total Depth of member
d’ Depth of compression reinforcement from compression face
d1 Depth of section enclosed within main reinforcement
ecs Strain in compression reinforcement
es Strain in tension reinforcement
Es Elastic modulus of steel
Єm Average steel strain at level where cracking is being considered
fcc Stress in compression concrete corresponding to e cs
fck Characteristics strength of concrete as that of 28 days cube
strength below which not more than 5% of the test Results may be
expected to fall
fs Stress in tension steel corresponding to e s
fy Characteristics strength of steel
Icr MOI of cracked section considering e qv. Area of tension and
compression rebar.
fsc Stress in compression steel corresponding to e cs
fst Tensile stress in steel under service load
Ks 0.5 + BC but no greater than 1
Pz Ultimate concentric load capacity
RC Reinforced Concrete
RS Response spectrum
S.F Shear Force
SLS Serviceability limit state
S.P Support Pier
Tc 0.25√fck
Tuc Ultimate shear strength of concrete
ULS Ultimate limit state
wcr crack width
Xu Depth of neutral axis
xul Limiting value of xu

Executive summary

This report emphasizes the structural design of ‘Residential Building, located

in Urlabari, Morang, Nepal. The IS code provisions are properly taken into
account while summarizing design assumptions, methodology, and compliance
with regulations and standards for the building.

The key goals of the project are to study and design building structures in
accordance with Indian standards code provisions. The building’s global response
to drift, displacement, and eccentricity are evaluated.

School Building PAGE |

6
STRUCTURAL ANALYSIS REPORT

Finite element analysis showed that the anticipated performance of the building
subjected to meet IS seismic hazard level requirements. The following
conclusions can be obtained from this report:

1. The building is designed to comply with the Indian Standards code.

2. Story drifts are within acceptable limits under the rules and regulations of
the code. ** The structural design is carried out on the provided architectural
drawing and soil report of the site. This study does not discuss any other features of the
building; it only emphasizes and limits itself to the technical aspects of the structure.

1. Project Details
Name of the Project: Residential Building

Location: Urlabari, Morang

Type of Building: The building covers a ground floor plinth area of 981
sq. ft. The building has been designed for a G+3 story
with a staircase cover.

The report has been prepared as a part of the structural engineering analysis
and design of buildings.

School Building PAGE |

7
STRUCTURAL ANALYSIS REPORT

Figure 1-1: Ground Floor Plan

School Building PAGE |

8
STRUCTURAL ANALYSIS REPORT

Building type: Residential Building

Location: Urlabari, Morang
Structural type: Special moment resisting RCC framed
Plinth area: As shown in architecture drawing
No. of story: G+3 storey with staircase cover
Floor to floor height: 3.04 m
Size of slab: RCC 5“ Thick slab
Size of beam: 12” x 15” (Main beam)
Size of column: 14” x 14”
Type of staircase: Doglegged
Type of foundation: Isolated Footing
Design Philosophy: Limit state design; Capacity Design
Concrete grade used: M20 for FOOTING, M25 for COLUMN and BEAM
Reinforcement: HYSD500
Dead load: Calculated as per IS 875 part I 1987
Live load: Calculated as per IS 875 part II 1987
Calculated as per IS code using the seismic coefficient
Seismic load:
method
Preliminary design: IS 456:2000
Soil type: Medium soil
Bearing capacity of
soil:

Building Grids
Direction Frame Naming
Transverse A-A, B-B, C-C, D-D
Longitudinal 1-1, 2-2, 3-3

School Building PAGE |

9
STRUCTURAL ANALYSIS REPORT

1.1 Building Design Parameters

The building consists of an RCC-framed structure, which is essentially an

assembly of cast-in-situ-concrete beams and columns. The floors and roof consist
of cast-in-place concrete slabs.
The structural system of the building is a special moment-resisting frame system
which has been designed to meet both strength and serviceability requirements
when subjected to gravity and earthquake loads, as well as ductility
requirements of IS 13920 - 1993.
For the design of the building, earthquake-resistant IS codes have been referred
to. For lateral load, necessary calculations are performed to comply with the
requirements of IS code.

1.2 Materials

1.2.1 Concrete
All components of plain and reinforced concrete unless specified in design are
M25 grade. Modulus of Elasticity [Ec]= 5000 √fck N/mm2(Cl. 6.2.3.1, IS 456:2000)
= 25000 N/mm2 for M25 Grade.
Poisson’s Ratio [U] = 0.2
Unit Weight = 25 KN/m3
Characteristic Strength [ƒck] = 25 N/mm2 for M25 grade.
The structural design strength is derived from the characteristic strength
multiplied by a coefficient of 0.67 and divided by the material partial safety
factor. The partial factor for concrete in flexure and axial load is 1.5.

1.2.2 Reinforcement steel

Reinforcement bars are to be in accordance with IS 456: specification for carbon

steel bars for the reinforcement of concrete is to be in accordance with IS 1786:
specification for highly deformed steel bars for the reinforcement of concrete.
The following design strengths are to be used for the design of concrete and
reinforcement.
Grade of Concrete: M25 and M20
Grade of rebar steel: High Yield Fe 500

School Building PAGE |

10
STRUCTURAL ANALYSIS REPORT

1.3 Load calculations

The following considerations are made during the loading of the structural
model:
 The loads distributed over the area are imposed on the area element and
the loads distributed over the length are imposed on the frame elements
whenever possible.
 Where such loading is not possible, equivalent conversion to different
loading distribution is carried to load the model near the real case as far
as possible.

1.3.1 Dead Load

Dead loads are calculated on the basis of unit weights of the specified
construction materials in accordance with IS 875 part 1 1987. The following are
assumed for detail load calculation.
 R.C.C Slab, Beam and Column = 25.0 KN/m3
 Screed (25mm thick) = 19.2 KN/m3
 Cement Plaster (20mm thick) = 20.40 KN/m3
 Marble Dressed = 26.50 KN/m3
 Standard Brick = 19.2 KN/m3

1.3.2 Superimposed Dead Loads

Based on the architectural drawing of the building, dead loads due to partition
walls, floor finish, and other special purpose services have been calculated. Wall
loads are applied underneath beam if the wall is rested on the beam.

1.3.3 Live Loads

Live load for the floor and Roof is taken from IS 875 part 2 as referred by the IS
code.
S.
Area type Load Unit
N
1 Terrace (Accessible) 1.5 KN/m2
2 Terrace (Inaccessible) 0.75 KN/m2
Staircase Balcony and
3 3 KN/m2
Passage
4 Partition Load 1 KN/m2
5 Washroom 2 KN/m2
6 Kitchen/Bedroom/Office 2 KN/m

School Building PAGE |

11
STRUCTURAL ANALYSIS REPORT

School Building PAGE |

12
STRUCTURAL ANALYSIS REPORT

1.3.4 Floor Finish Loads

For marble finishing
Depth of Finishes = 0.055 m
Marble Dressed = 26.5 KN/m³
Weight per square meter = 0.055 x
= 1.46 KN/m²
26.5
For plaster finishing
Depth of Finishes = 0.055 m
20.40
Screed/ Plaster =
KN/m³
Weight per square meter = 0.055 x 1.122
=
20.4 KN/m²

1.3.5 Seismic Loads

The design seismic force is transmitted throughout the building's height to the
various lateral load-resisting elements acquired via the use of both the linear
static (seismic coefficient) and dynamic response spectrum techniques of study.
The soil type is type II with 5% damping to determine the average response
acceleration.

In ETABS 2023 v21, the seismic load is applied to the building using a user-
defined lateral load pattern, taking into account IS 1893 (part 1): 2016. This load
scenario is considered to be static linear, and the required data are provided
under the following assumptions.

 Calculation of time period

The design base shear (V b) is calculated using a fundamental period T calculated
using:

0.75
= 0.075h [IS 1893 (Part 1): 2016, Cl. 7.6.2]

Where,
Where, h= Height of the building in m is defined in clause 7.6.1 and
d=Base dimension of the building at the plinth level in meters, along the
considered direction of the lateral force


School Building PAGE |

13
STRUCTURAL ANALYSIS REPORT

 Calculation of Seismic Base shear

The total design lateral force or design seismic base shear (Vb) along any
principal direction shall be determined by the following expression:

𝑉𝑏= Ah× 𝑊

Where Ah= Design horizontal acceleration spectrum value as per 6.4.2. IS 1983
(Part I): 2016,

Using the fundamental natural period Ta as per 7.6 in the considered direction of
vibration, and W= Seismic weight of the building as per clause 7.4.2

The design Horizontal Seismic coefficient Ah for a structure shall be determined

by the following expression:

 Vertical Distribution of Base Shear to Different Floor Level

The base shear is distributed as lateral seismic force Qi induced at each level I
and is calculated as:

Where,

Qi= design lateral force at floor i,

Wi= Seismic weight of floor i

hi= height of floor i measured

from base; and

n= number of storey in building

School Building PAGE |

14
STRUCTURAL ANALYSIS REPORT

1.4 Load Combination

The load combinations are based on NBC 105-2020. The following load
combinations are specified as per NBC 105, cl. 3.6:
 1.5 (DL + LL)
 1.5 (DL + EQ(x))
 1.5 (DL – EQ(x))
 1.5 (DL + EQ(y)
 1.5 (DL – EQ(y)
 1.2 (DL + LL + EQ(x)
 1.2 (DL + LL – EQ(x)
 1.2 (DL + LL + EQ(y)
 1.2 (DL + LL – EQ(y)
 0.9DL + 1.5EQ(x)
 0.9DL - 1.5EQ(x)
 0.9DL + 1.5EQ(y)
 0.9DL - 1.5EQ(y)
 1.5DL

Design Assumptions

 Concrete Grade, M25

fck= 25 MPa
 Steel Grade, Fe 500
fy= 500 MPa for all
Load
Load Name Description Unit Remarks
Type
Self-weight of the
Dead Dead KN/m2
structure
LIVE Live Imposed Load KN/m On floor slab
Roof Live Live Roof Live KN/m2 On floor slab
WALL LOAD Dead Partition Wall Load KN/m On floor beams
FINISHES Dead Floor Finish Load KN/m2 On floor slab
Seismi
EQX Seismic Coefficient NBC X+0.1Y
c
Seismi
EQY Seismic Coefficient NBC Y+0.1X
c

For the above loads and load combinations, the design of beams and columns is
carried out by the ETABS.

School Building PAGE |

15
STRUCTURAL ANALYSIS REPORT

Table 1.4-1 : Mass Source

Multiplie
Load
r
DEAD 1
LIVE <3 0.25
LIVE >=3 0.5
WALL 1
FINISH 1
PWL 1

2. Structural Analysis and Design of Main Building

The analysis and design have been carried out using software called ETABS
v21.2, which is a special-purpose computer program developed specifically for
building structures. It provides the Structural Engineer with all the tools
necessary to create, modify, analyze, design, and optimize the structural
elements in a building model. The building geometry based on architectural
drawings has been generated using above-named software. The dead load, live
load, and lateral loads were supplied to the digital models as per the standard
code of practices. Several analysis run were performed to achieve the best result
to meet the design and service requirements.
For the analysis, the following loading parameters were considered:
i. Self-weight of the frames and slabs
ii. Floor finishing dead loads
iii. Fixed wall loads as per architectural drawings
iv. Partition wall loads as per architectural drawings only.
v. Live loads

2.1 Preliminary Sizing

For the analysis, dead load is also necessary which depends upon the size
of member itself. So it is necessary to pre-assume logical size of member which
will neither overestimate the load nor under estimate the stiffness of the
building. So, the tentative sizes of the structural elements are determined
through the preliminary design so that the pre-assumed dimensions may not
deviate considerably after analysis thus making the final design both safe and
economical. Tentative sizes of various elements have been determined as
follows:

School Building PAGE |

16
STRUCTURAL ANALYSIS REPORT

2.1.1 Slab

Preliminary design of slab is done as per the deflection criteria as directed by

code Clause 23.2.1 of [IS 456: 2000]. The cover provided is 20 mm and the grade
of concrete used in the design is M20.
According to which,
Span ≤ (Mft x Mfc) x Basic Value
Eff. Depth
Where, the critical span is selected which is the maximum shorter span among
the all slab element. This is done to make uniformity in slab thickness. The
amount of reinforcement will be varied slab to slab but the thickness will be
adopted corresponding to the entire slab.

2.1.2 Beam

Preliminary design of the beam is done as per the deflection criteria as directed
by code Clause 23.2.1 of [IS 456: 2000] and ductility criteria of ACI code. The
cover provided is 30 mm and the grade of concrete used in the design is M25.
According to which,
Span ≤ (Mft x Mfc) x Basic Value x Correction Factor
Eff. Depth for span x Correction Factor for Flange
But,
According to Ductility code, Spacing of Stirrups in beam should not exceed d/4 or
8 times diameter of minimum size of bar adopted and should not greater than
100mm. So, for considering construction difficulties in actual field, it is logical to
use d/4 as spacing as per the construction practice in Nepal.

2.1.3 Column

Preliminary design of column is done from the assessment of approximate

factored gravity loads and live loads coming up to the critical section. To
compensate the possible eccentric loading and earthquake loads the size is
increased by about 25% in design. For the load acting in the column, live load is
decreased according to IS 875: 1978. Initially a rectangular column is adopted in
this building project so as to provide internal aesthetics required from
architecture point of view but the column size and shape will vary as per the
requirement for the analysis, design and aesthetic value. The cover provided is
40 mm and the grade of concrete used in the column design is M25.

2.2 3D modelling of the building

i. 3D model of the building
ii. Plan of the building
iii. Elevation of the building

School Building PAGE |

17
STRUCTURAL ANALYSIS REPORT

Figure 2-2: 3D Model of building

Table 2-2: Section property and modifiers
Property Modifiers
Materi Design
Name Depth Width Shear Flexural
al type
stiffness stiffness
BM 12” x
M25 15” 12” Beam 0.4 0.4 0.35 0.35
15”
CL 14” x
M25 14” 14” Column 0.4 0.4 0.7 0.7
14”

School Building PAGE |

18
STRUCTURAL ANALYSIS REPORT

Figure 2-3: Plan of the building

School Building PAGE |

19
STRUCTURAL ANALYSIS REPORT

Figure 2-4: Elevation of the building

School Building PAGE |

20
STRUCTURAL ANALYSIS REPORT

2.3 Load Applied on Building:

Figure 2-5: Wall load on beam

Load coming from the weight of the wall is applied on the beam underneath the
wall. If there is not any beam below the wall, load is applied to nearby beam in
the direction of wall. The application of wall load is shown in the figure below.

School Building PAGE |

21
STRUCTURAL ANALYSIS REPORT

Table 2-3: Wall load calculation

Floor
Beam Thickne Densit
Heigh Load Calculated (KN/m)
Particular depth ss y
t
(m) (m) (m) (KN/m3 Full wall 30 % opening
Full brick wall 3.04 0.38 0.25 19.2 13.5 9.4
Half brick
3.04 0.38 0.127 19.2 6.82 4.8
wall

School Building PAGE |

22
STRUCTURAL ANALYSIS REPORT

Figure 2-6: Live load applied on floor

School Building PAGE |

23
STRUCTURAL ANALYSIS REPORT

Table 2-4: Live load intensity

S.
Area type Load Unit
N
1 Terrace (Accessible) 1.5 KN/m2
2 Terrace (Inaccessible) 0.75 KN/m2
Staircase Balcony and
3 3 KN/m2
Passage
4 Partition Load 1 KN/m2
5 Washroom 2 KN/m2
6 Bedroom 2 KN/m

Figure 2-7: Floor Finish load on floor

Table 2-5: Floor Finish Load Calculation
For marble finishing
Depth of Finishes = 0.055 m
Marble Dressed = 26.5 KN/m³
Weight per square meter = 0.055 x
= 1.46 KN/m²
26.5
For plaster finishing

School Building PAGE |

24
STRUCTURAL ANALYSIS REPORT

Depth of Finishes = 0.055 m

20.40
Screed/ Plaster =
KN/m³
Weight per square meter = 0.055 x 1.122
=
20.4 KN/m²

Figure 2-8: Dead load of steps on waist slab

Unit weight of masonry 19.2
=
(fck) KN/m³
Width of stair (W) = 1.2 m
Length of flight (L) = 2.300 m
Nos. of steps = 9
1.50
Dead load of steps =
KN/m²

School Building PAGE |

25
STRUCTURAL ANALYSIS REPORT

Figure 2-9: Diaphragm Extent

School Building PAGE |

26
STRUCTURAL ANALYSIS REPORT

2.4 Analysis Result:

Figure 2-10: Deformed shape under dead load and mode 1

School Building PAGE |

27
STRUCTURAL ANALYSIS REPORT

Figure 2-11: Deformed shape under modal load case (Mode 2 and 3)

2.4.1 Auto Seismic Load Definitions

School Building PAGE |

28
STRUCTURAL ANALYSIS REPORT

Table 2-6: Auto Seismic Load Data

TABLE: Load Pattern Definitions - Auto Seismic - IS 1893 2016
Ecc Botto Site Base
Rati Top m Z Typ I R Coeff Weigh Shear
Name o Story Story e Used t Used kN
Story 0.3 1.
EQx 0.05 4 Base 6 II 2 5
EQx(1/ Story 0.3 1. 0.0696
3) 0.05 4 Base 6 II 2 5 8 3654 254.6013
EQx(2/ Story 0.3 1. 0.0696
3) 0.05 4 Base 6 II 2 5 8 3654 254.6013
EQx(3/ Story 0.3 1. 0.0696
3) 0.05 4 Base 6 II 2 5 8 3654 254.6013
Story 0.3 1.
EQy 0.05 4 Base 6 II 2 5
EQy(1/ Story 0.3 1. 0.0696
3) 0.05 4 Base 6 II 2 5 8 3654 254.6013
EQy(2/ Story 0.3 1. 0.0696
3) 0.05 4 Base 6 II 2 5 8 3654 254.6013
EQy(3/ Story 0.3 1. 0.0696
3) 0.05 4 Base 6 II 2 5 8 3654 254.6013

Table 2-7: Lateral load in stories

School Building PAGE |

29
STRUCTURAL ANALYSIS REPORT

Figure 2-12: Base shear distribution along the X and Y

School Building PAGE |

30
STRUCTURAL ANALYSIS REPORT

2.4.2 Modal Analysis

Modal analysis was performed to determine the free vibration and dynamic
behavior of the building.
Table 2-8 : Modal Participating Mass Ratios
TABLE: Modal Participating Mass Ratios
Case Mode Period UX UY SumUX SumUY RZ SumRZ
sec
Modal 1 0.768 0.0007 0.82 0.0007 0.82 0.0204 0.0204
Modal 2 0.696 0.8225 0.0029 0.8232 0.8229 0.0249 0.0452
Modal 3 0.627 0.029 0.0236 0.8522 0.8464 0.81 0.8553
Modal 4 0.256 0.0001 0.0987 0.8523 0.9451 0.012 0.8673
Modal 5 0.241 0.0966 0.0013 0.9489 0.9464 0.0057 0.8729
Modal 6 0.21 0.0075 0.0139 0.9564 0.9603 0.0849 0.9578
Modal 7 0.159 0.0114 0.021 0.9678 0.9813 0.0036 0.9614
Modal 8 0.154 0.0219 0.0065 0.9897 0.9878 0.0068 0.9682
Modal 9 0.135 4.215E-05 0.0021 0.9898 0.9899 0.0226 0.9908
Modal 10 0.13 0.0003 0.0088 0.99 0.9987 1.026E-05 0.9908
Modal 11 0.122 0.0099 0.0003 1 0.9989 0.0012 0.992
Modal 12 0.11 1.067E-05 0.0011 1 1 0.008 1

The first modal time period of the building is 0.768 sec. In total 12 modes
were considered and 90% mass participation was obtained for mode 5.

Table 2-9: Centers of Mass and Rigidity

TABLE: Centers Of Mass And Rigidity
Story Mass X Mass Y XCCM YCCM XCR YCR ex ey
kg kg m m m m m m
Story1 94262.81 94262.81 5.55 3.52 5.80 3.83 -0.25 -0.31
Story2 93197.17 93197.17 5.52 3.54 5.76 3.78 -0.25 -0.24
Story3 47751.89 47751.89 6.81 3.36 5.95 3.75 0.86 -0.39
Story4 9212.75 9212.75 9.10 2.25 9.15 2.50 -0.05 -0.25

2.4.3 Displacement and drift of the building

As per Cl. No. 7.11.1 of IS 1893 (part –1):2016, storey drift in any storey shall
not exceed 0.004 time the storey height, under the action of design base shear
Vb.

School Building PAGE |

31
STRUCTURAL ANALYSIS REPORT

Figure 2-13: Story drift along X and Y direction

Storey drift in any storey shall not exceed 0.004 times the storey height. (CL.
7.11.1, IS 1893 (part 1): 2016. OK

School Building PAGE |

32
STRUCTURAL ANALYSIS REPORT

Figure 2-13: Story displacement along X and Y direction

Table 2-9: Check for drift; Story Drift Along X-axis

Output Case Directio % of Check
Storey Case Type n Drift Drift <0.4%
Linstati 0.00
Story 4 Eqx c X 1 0.116 OK

School Building PAGE |

33
STRUCTURAL ANALYSIS REPORT

Linstati 0.00
Story3
Eqx c X 2 0.155 OK
Linstati 0.00
Story2
Eqx c X 2 0.212 OK
Linstati 0.00
Story1
Eqx c X 2 0.154 OK
Linstati
Base
Eqx c X 0 0.000 OK

Story Drift Along Y-axis

Output Case Directio % of Check
Storey Case Type n Drift Drift <0.4%
Linstati 0.00
Story 4 Eqx c Y 1 0.141 OK
Linstati 0.00
Story3
Eqx c X 2 0.220 OK
Linstati 0.00
Story2
Eqx c X 3 0.286 OK
Linstati 0.00
Story1
Eqx c X 2 0.195 OK
Linstati
Base
Eqx c X 0 0.000 OK

As per IS 1893, the story drifts in any story due to specified design lateral force
with a partial load factor of 1.0, shall not exceed 0.004 times the story height.

2.4.4 Irregularity check

Table 2-10: Check for mass irregularity

150% of the (M) of below Check if Mi

storey Mass (Mi)
floor (Mi') <Mi'

Story4 9212.75 71627.835 REGULAR

Story3 47751.89 139795.755 REGULAR
Story2 93197.17 141394.215 REGULAR
Story1 94262.81 - ``

As per is 1893; 2016 mass irregularity shall be considered to exist, when the
seismic weight (as per 7.7) of any floor is more than 150 percent of that of the
floors below.

Table 2-11: Check for stiffness irregularity; Along the X-axis

70% of the stiffness of check if

Storey Stiffness (K)
above storey (K') (K>K')
Story4 13502.48 0
Story3 33215.603 9451.736 REGULA

School Building PAGE |

34
STRUCTURAL ANALYSIS REPORT

R
REGULA
Story2 40221.454 23250.9221 R
REGULA
Story1 59346.503 28155.0178 R

Along Y-axis

Store Stiffness 70% of the stiffness of above check if

y (K) storey (K') (K>K')
Story
0
4 11001.236
Story REGULA
3 26919.401 7700.8652 R
Story REGULA
2 32634.36 18843.5807 R
Story REGULA
1 50327.951 22844.052 R

As per 1893; 2016 a soft storey is considered to exist if the lateral stiffness is
less than 70% of that in the storey above or less than 80% of the average lateral
stiffness of the 3 storey above.

Table 2-12: Check for torsion; Along X-axis

Store Allowable
Δmax Δmin (Δmax)/(Δmin)
y (Δmax)/(Δmin)
Story 19.15 16.94
1.131 1.5(OK)
4 9 7
Story 15.97 14.31
1.116 1.5(OK)
3 7 8
Story 11.24 10.10
1.112 1.5(OK)
2 3 7
Story
4.78 4.291 1.114 1.5(OK)
1
Base 0 0 1.5(OK)

Along Y-axis

Store
Δmax Δmin Δmax)/(Δmin) Allowable (Δmax)/(Δmin)
y
Story 25.36 21.23
1.195
4 5 1
Story 21.51 18.00
1.195 1.5(OK)
3 3 5
Story 14.79 12.32
1.200 1.5(OK)
2 3 3
Story 6.071 5.064 1.199 1.5(OK)

School Building PAGE |

35
STRUCTURAL ANALYSIS REPORT

1
Base 0 0 0.000 1.5(OK)

Torsion irregularity is considered to exist where the maximum horizontal

displacement of any floor in the direction of the lateral force (applied at the
center of mass) at one end of the story is more than 1.5 times its minimum
horizontal displacement at the far end of the same story in that direction.

School Building PAGE |

36
STRUCTURAL ANALYSIS REPORT

2.4.5 Force/Stress Diagrams:

Figure 2-14: Axial Force Diagram

School Building PAGE |

37
STRUCTURAL ANALYSIS REPORT

Figure 2-15: Shear Force Diagram

School Building PAGE |

38
STRUCTURAL ANALYSIS REPORT

Figure 2-16: Bending Moment Diagram

School Building PAGE |

39
STRUCTURAL ANALYSIS REPORT

Figure 2-17: Model Check

2.5 Design of element:

The design of all structural elements is done using ‘Limit State Method’. All
relevant Limit State is considered in design to ensure adequate safety and
serviceability. The design includes design for durability, construction and use in
service should be considered as a whole. The realization of design objectives
requires compliance with clearly defined standards for materials, production,
workmanship, and also maintenance and use of structure in service.
This section includes all the design process of sample calculation for a single
element as column, beam, slab and foundation.

School Building PAGE |

40
STRUCTURAL ANALYSIS REPORT

2.5.1 Design of footing

Figure 2-18: Base Reactions from ETABS

The footing is provided under RCC columns of a framed structure to distribute
the load on a larger area. If condition of shear is satisfied, then the thickness of
footing is reduced at the edges for the economy.
The bending moment, beam shear and punching shear govern the thickness or
depth of the footing near the column face.

School Building PAGE |

41
STRUCTURAL ANALYSIS REPORT

1.1.1.1Design of Isolated footing

School Building PAGE |

42
STRUCTURAL ANALYSIS REPORT

School Building PAGE |

43
STRUCTURAL ANALYSIS REPORT

2.5.2 Design of column

The design of column section can be made either by working stress method or by
the limit state method. The working stress method of design of column is based
on the behavior of the structure at working load ensuring that the stress in
concrete and steel do not exceed their allowance values.
It is assumed to possess adequate safety against collapse. The limit state
method of design of column is based on the behavior of the structure at collapse
ensuring adequate margin safety. The serviceability limits of deflections and
cracks are assumed to be satisfied as the column being primarily a compression
member has very small deflections and cracks.

Figure 2-19: Design reinforcement detail (Elevation view)

School Building PAGE |

44
STRUCTURAL ANALYSIS REPORT

Figure 2-20: Design reinforcement detail (Elevation view

Figure 2-21: Design reinforcement detail (Elevation view)

ETABS Concrete Frame Design
IS 456:2000 + IS 13920:2016 Column Section Design (Summary)

School Building PAGE |

45
 STRUCTURAL ANALYSIS REPORT

Column Element Details

Elemen Unique Section Station Length
Level Combo ID LLRF Type
t Name ID Loc (mm)
CL- 0.9DL- Ductile
Story1 C6 6 0 3050 0.672
14'X14' 1.5EQ+y Frame

Section Properties
Cover (Torsion)
b (mm) h (mm) dc (mm)
(mm)
356 356 56 30

Material Properties
Lt.Wt Factor
Ec (MPa) fck (MPa) fy (MPa) fys (MPa)
(Unitless)
25000 25 1 413.69 413.69

Design Code Parameters

ɣC ɣS
1.5 1.15

Axial Force and Biaxial Moment Design For Pu , Mu2 , Mu3

Rebar
Design Pu Design Mu2 Design Mu3 Minimum M2 Minimum M3 Rebar %
Area
kN kN-m kN-m kN-m kN-m %
mm²
168.0308 -62.8862 3.3606 3.3606 3.3606 1047 0.83

Axial Force and Biaxial Moment Factors

School Building PAGE |

46
 STRUCTURAL ANALYSIS REPORT

Initial Additional Minimum

K Factor Length
Moment Moment Moment
Unitless mm
kN-m kN-m kN-m
Major 0.63249
2675 -0.8564 0 3.3606
Bend(M3) 9
Minor 0.65317
2675 -31.8218 0 3.3606
Bend(M2) 3

Shear Design for Vu2 , Vu3

Shear Vu Shear Vc Shear Vs Shear Vp Rebar Asv /s
kN kN kN kN mm²/m
Major, Vu2 41.8642 60.1063 42.7195 41.8642 395.86
Minor, Vu3 39.8534 60.1063 42.7195 39.8534 395.86

Joint Shear Check/Design

Joint Shear Shear Shear Shear Joint Shear
Force VTop Vu,Tot Vc Area Ratio
kN kN kN kN cm² Unitless
Major Shear,
N/N N/N N/N N/N N/N N/N
Vu2
Minor Shear,
N/N N/N N/N N/N N/N N/N
Vu3

(1.4) Beam/Column Capacity Ratio

Major Minor
Ratio Ratio
N/N N/N

Additional Moment Reduction Factor k (IS 39.7.1.1)

Ag Asc Puz Pb Pu k
cm² cm² kN kN kN Unitless
1750.61 654.44 168.03
1267.4 10.5 1
37 46 08

Additional Moment (IS 39.7.1)

Section Ma
Consider Length KL/Depth KL/Depth KL/Depth
Depth Moment (kN-
Ma Factor Ratio Limit Exceeded
(mm) m)
Major Bending
Yes 0.877 356 4.753 12 No 0
(M3 )

School Building PAGE |

47
 STRUCTURAL ANALYSIS REPORT

Section Ma
Consider Length KL/Depth KL/Depth KL/Depth
Depth Moment (kN-
Ma Factor Ratio Limit Exceeded
(mm) m)
Minor Bending
Yes 0.877 356 4.908 12 No 0
(M2 )

Notes:

N/A: Not Applicable

N/C: Not Calculated

N/N: Not Needed

1.1.1.2Sample Design of Column

Governing Combo ID = 0.9DL-1.5EQ+y
Storey = GF
Column Type = C1

1) Material Properties:
Grade of concrete used (fck) = M25
Grade of steel used (fᵧ) = Fe500
2) Member properties
Length of the column = 3.05 m
Depth of beam = 355 mm
Effective length factor (Kx) = 0.85
Effective length factor (Ky) = 0.85
Unsupported length of the column = 2.95 m
Effective length of the column (Lex) = 2.59 m
Effective length of the column (Ley) = 2.59 m
Width of column (Dx) = 355 mm
Depth of column (Dy) = 355 mm
Clear cover = 40 mm
Confinement rebar = 10 mm
Effective Cover = 60 mm
3) Load Data
Axial load of column (Pa) = 167.00 KN
Moment about X-axis
Mx,1 = 62.00 KN-m
Mx,2 = 4.00 KN-m
Moment about Y-axis
My,1 = 46.00 KN-m
My,2 = 15.00 KN-m
4) Flexural design of column

School Building PAGE |

48
STRUCTURAL ANALYSIS REPORT

Slenderness check
< 12 , Design as short
lex/Dx = 6.27 column
< 12 , Design as short
ley/Dy = 6.27 column
Minimum Eccentricities:
ex,min = 20 mm > 20 mm
ey,min = 20 mm > 20 mm
Moment due to Eccentricities
Muxe = 4.0 KN-m = Pu x ey
Muye = 4.0 KN-m = Pu x ex
Hence, design moment Mux = 46.00 KN-m
Muy = 15.00 KN-m
For bi-axially loaded column,
Assume percentage of steel (pt) = 0.9 %
Gross area (Ag) = 1040.00 mm²
Moment carrying capacity of column
(Mux,y),
Along X-axis
d'/D = 0.10
Pt/fck = 0.16
Pᵤ/fckbD = 0.19
Mᵤ/fckbD² = 0.22 From graph of SP16,
Mux1 = 352.00 KN-m
Along Y-axis
d'/D = 0.10
Pt/fck = 0.16
Pᵤ/fckbD = 0.19
Mᵤ/fckb²D = 0.22 From graph of SP16,
Muy1 = 352.00 KN-m
Check for interaction formula
Axial Load Carrying capacity of
= 855.80 KN =0.45f𝒸ₖA𝒸+0.75fᵧAₛₜ
Column (Puz)
Pu/Puz = 0.18
Mu/Mux1 = 0.83
Mu/Muy1 = 0.13
α = 0.98
Since, α < 1, so take α = 1.
(Mᵤ/Mᵤₓ₁)ᵃ + (Mᵤ/Mᵤᵧ₁)ᵃ = 0.96 ≤1
OK
Area of steel required (Aₛₜ) = 1080.00 mm²
No. of Φ20 mm bars = 0 nos.
No. of Φ16 mm bars = 4 nos.
No. of Φ12 mm bars = 4 nos.
Max bar size provided (Φ) = 16 mm
Provide 4-16Φ-4-12Φ bar as longitudinal reinforcement.
Area of steel provided (Aₛₜ) = 1256.63 mm²
should be within range 0.8
Percentage of steel provided (p%) = 1% - 6%
OK

5) Check for shear

School Building PAGE |

49
STRUCTURAL ANALYSIS REPORT

Design shear reinforcement from

= 395.00 mm²
ETABS
No. of legs provided = 2 nos.
Size of ties (Φₜ) = 8 mm
Area of shear reinforcement = 100.53
Spacing of ties required = 181.46
which should be < i) 16Φ
Spacing of ties provided = 100.00 = 320 mm
OK < ii) 300 mm
< iii) least lateral dim. =
400 mm
Check for extra ties
No. of bar per face = 3.0 nos.
Spacing between corner bars = 300 mm < 48Φₜ
Spacing between longitudinal bars = 150 mm <75 mm
Hence, extra stirrups isn't required. However, provide 8mm closed type extra stirrups.

OK

2.5.3 Design of Beam

The design of beams requires the determination of the cross-sectional
dimensions and reinforcement details to satisfy both serviceability and
strength requirements. The serviceability requirement for deflection is
controlled by the effective span to effective depth ratio. Generally, the
depth of the beam is large and governed by the strength requirement. The
spacing of reinforcement controls the serviceability requirement for crack.
In beams, the spacing of reinforcement bars is small and governed by the
minimum spacing requirement than the maximum spacing for crack
control. The reinforcements are provided to satisfy strength requirements.
The detailing of longitudinal and transverse bars should satisfy the
bending, shear, and bond requirements. The bending moment and shear
are determined from the analysis generally based on the elastic theory.

Beams are designed for the worst conditions. So, the maximum values
from the combination have been used for the design .

School Building PAGE |

50
STRUCTURAL ANALYSIS REPORT

Figure 2-24: Design shear reinforcement details (Plan view)

School Building PAGE |

51
STRUCTURAL ANALYSIS REPORT

Figure 2-25: Design reinforcement details (Plan view)

ETABS Concrete Frame Design

School Building PAGE |
52
 STRUCTURAL ANALYSIS REPORT

IS 456:2000 + IS 13920:2016 Beam Section Design (Summary)

Beam Element Details

Elemen Unique Section Station Length
Level Combo ID LLRF Type
t Name ID Loc (mm)
BM 1.5DL- Ductile
Story1 B10 50 178 3657.6 1
12"X15" 1.5EQ+x Frame

Section Properties
b (mm) h (mm) bf (mm) ds (mm) dct (mm) dcb (mm)
305 375 305 0 25 25

Material Properties
Lt.Wt Factor
Ec (MPa) fck (MPa) fy (MPa) fys (MPa)
(Unitless)
25000 25 1 413.69 413.69

Design Code Parameters

ɣC ɣS
1.5 1.15

Factored Forces and Moments

Factored Factored Factored Factored
Mu3 Tu Vu2 Pu
kN-m kN-m kN kN
-48.8653 0.0963 55.4379 0.1606

Design Moments, Mu3 & Mt

School Building PAGE |

53
STRUCTURAL ANALYSIS REPORT

Factored Factored Positive Negative

Moment Mt Moment Moment
kN-m kN-m kN-m kN-m
-48.8653 0.1262 0 -48.9916

Design Moment and Flexural Reinforcement for Moment, Mu3 & Tu

Design +Momen
Design -Moment Minimum Required
+Momen t
-Moment Rebar Rebar Rebar
t Rebar
kN-m mm² mm² mm²
kN-m mm²
Top (+2
-48.9916 416 0 416 310
Axis)
Bottom (-2
0 208 0 0 208
Axis)

Shear Force and Reinforcement for Shear, Vu2 & Tu

Shear Ve Shear Vc Shear Vs Shear Vp Rebar Asv /s
kN kN kN kN mm²/m
68.9884 0 69.5505 37.2546 552.41

Torsion Force and Torsion Reinforcement for Torsion, Tu & VU2

Tu Vu Core b1 Core d1 Rebar Asvt /s
kN-m kN mm mm mm²/m
53.172
0.1071 275 345 294.91
8

1.1.1.3Sample Design of Beam

1) Material Properties:
Grade of concrete (fck) = 25 MPa
Grade of steel (fy) = 500 MPa
2) Section Properties:
Width of Beam (b) = 300 mm
Overall depth of beam (D) = 375 mm
Clear cover (cc) = 25 mm
Effective cover (d') = 35 mm = cc + Φv + Φ/2
Effective depth of beam (d) = 341 mm = D-d'
Effective length of beam (l) = 4.70 m
3) Flexural Design of Beam:
1.5DL-
=
Governing combo 1.5EQ+x
Design Moment = 49.00 KN-m

School Building PAGE |

54
STRUCTURAL ANALYSIS REPORT

Factored Torsion moment (Mt) = 0.19 KN-m

Ultimate Design Moment (Mu) (As per IS 456:2000, cl. = 65.88 KN-m
41.4.2)
Limiting depth of neutral axis (xu,lim) = 171 mm
Then, Limiting Moment ( Mu,lim) = 93.83 KN-m
Since Mu > Mu,lim, the section is = Doubly reinforced section
For Doubly reinforced section,
Tension reinforcement
Area of steel (Ast1) = 186 mm²
For remaining moment, M = 12.05 KN-m
Area of steel (Ast2) = 56 mm²
Total area of tension steel (Ast) = 205mm²
=
Depth of neutral axis (xu) 201 mm
=
Ast, required 185 mm²
No. of Φ20 mm bars = 0 nos
No. of Φ16 mm bars = 3 nos
No. of Φ12 mm bars = 0 nos
Therefore, Ast, provided = 210 mm²
Compression reinforcement
=
For remaining moment, M 12 mm²
=
d'/d 0.09
=
fsc
411.17 N/mm²
=
fcc
8.92 N/mm²
=
For area of compression reinforcement (Asc) 89 mm²
No. of Φ20 mm bars = 2 nos
No. of Φ16 mm bars = 2 nos
No. of Φ12 mm bars = 0 nos
Total area of compression steel (Asc) = 340 mm²
Safe in
flexure
4) Shear Design of Beam:
Given Ultimate Shear (Vu) = 56.00 KN
Shear force due to formation of plastic hinge at
= 5.92 KN
the end of beam (Vp)
Max. design shear force at ends (Vdu) = 60.92 KN
Ultimate Max design Shear (Vu) (As per IS 456:2000, = 80.27 KN = Vdu + 1.6Tu/b
cl. 41.3.1)
Required shear reinforcement = 290 mm²/m
As per IS 13920:2016, cl 6.3.4: In the calculation of design shear force capacity of RC
beams, contribution of the shear strength of concrete shall not be considered.
Percent of tension reinforcement (p%) = 0.18% = 100 x Ast/bd
Nominal shear strength of concrete (τuc) = -
(τuc,max) = 3.10 N/mm²
Vuc = - = τuc x bd
Vuc,max = 292.44 KN
OK
Consider shear reinforcement of diameter (Φv) = 10 mm

School Building PAGE |

55
STRUCTURAL ANALYSIS REPORT

No. of legs = 2 nos

Asv = 157 mm²
Spacing of shear reinforcement (sv) (As per cl. = 0.87fyAsvd/(Vu-
= 150 mm Vuc)
26.5.1.5)
Safe in
shear
Hence, provide 2L-10 mm vertical stirrups @100 mm c/c spacing.
5) Check for Deflection: (As per IS 456:2000, cl. 23.2.1)
Required tension reinforcement % (Pt) = 0.18%
Provided tension reinforcement % (Pt) = 0.2%
Basic value of span to effective depth ratio (α) = 26
Modification factor for span > 10m (β) = 1
Mu/bd2 = 3.02
fs = 0.58fy x [Ast,required/ Ast,provided] = 210.68 N/mm²
Required modification factor for tension
reinforcement = 2.05
Actual modification factor for tension
1.8
reinforcement (γ) =
Modification factor for compression
1.00
reinforcement (λ) =
Reduction factor (δ) = 1.00
Allowable span to effective depth ratio (L/d) = 29.01
Calculated span to effective depth ratio (L/d) = 12.65
(l/d)max >
Safe in deflection (l/d)provided

School Building PAGE |

56
STRUCTURAL ANALYSIS REPORT

1.1.1.4Deflection check in beam

Figure 2-26: Bending moment diagram (1.5DL + 1.5LL combination)

Figure 2-27: Force diagram for critical beam

School Building PAGE |

57
STRUCTURAL ANALYSIS REPORT

The maximum deflection in beam is 3.515 mm which is less than the allowable
deflection.

2.5.4 Design of slab

School Building PAGE |

58
STRUCTURAL ANALYSIS REPORT

School Building PAGE |

59
STRUCTURAL ANALYSIS REPORT

School Building PAGE |

60
STRUCTURAL ANALYSIS REPORT

Summary
Grade of concrete = 25 Grade of steel = 500 MPa
MPa (TMT)
Provide 150 mm thick slab with Ø8 mm rebar @ 150 mm c/c & Ø8 mm distribution
rebar @ 150 mm c/c bar

School Building PAGE |

61
STRUCTURAL ANALYSIS REPORT

School Building PAGE |

62
STRUCTURAL ANALYSIS REPORT

2.5.5 Design of Staircase

School Building PAGE |

63
STRUCTURAL ANALYSIS REPORT

School Building PAGE |

64
STRUCTURAL ANALYSIS REPORT

School Building PAGE |

65
STRUCTURAL ANALYSIS REPORT

Design Summary
COLUMN DETAIL
Grade of concrete = M25
Grade of rebar = Fe500
Max./Min
S. Typ Section From Base to From 3.05m to From 6.1 m
Node percentag Lateral Ties
N. e Size 3.05 m 6.1 m to All above
e rebar
A1,A2,A3,B1,
4 – Φ16 + 4 – 4 – Φ16 + 4 – 0.8% & Φ10 @ 100/150 mm
1 C1 14" X 14" B2,B3,C1,C2, 4 – Φ16 + 4 – Φ12
Φ12 Φ12 1.11% c/c
C3,D1,D2
4 – Φ16 + 4 – 0.8% & Φ10 @ 100/150 mm
2 C2 14" X 14" D3 8 – Φ16 4 – Φ16 + 4 – Φ12
Φ12 1.27% c/c

BEAM DETAIL
Grade of concrete = M25
Grade of rebar = Fe500
S.N Section Laye
Type Floor Level Longitudinal Reinforcement Lateral Ties
. Size r
Through
Extra Bar Extra Bar
Bar
Top - 2-Φ12 -
2L-Φ8 @ 100/150 mm
1 TIE BEAM - 10" X 10" Botto
- 2-Φ12 - c/c
m
Top 2-Φ12
Plinth 2L-Φ8 @ 100/150 mm
2 +-0 10” x 15” Botto 2-Φ12
Beam - - c/c
m
Top - 3-Φ16 -
Floor 2L-Φ8 @ 100/150 mm
3 +3.05 12” x 15” Botto 2-Φ16
Beam - - c/c
m
Floor , Top - 3-Φ12 - 2L-Φ8 @ 100/150 mm
4 12” x 15”
Beam +6.1,+9.15,+12 Botto - 3-Φ12 - c/c

School Building P A G E | 66
STRUCTURAL ANALYSIS REPORT

m
.2

FOOTING DETAIL
Grade of concrete = M20
Grade of rebar = Fe500

Length X Overall
Type Nodes Breadth Depth Reinforcement Remarks
(mm x mm) (mm)

Φ12 @ 150 mm c/c (X-axis) in top and

Isolate bottom
Including All Area 1800 X 1800 400
d
Φ12 @ 150 mm c/c (Y-axis)

STAIR WAIST SLAB DETAIL

Grade of concrete = M25
Grade of rebar = Fe500
S.N Length X Overall Remark
Floor Level Reinforcement
. Breadth Depth s
Layer Rebar
Top/ Φ12 @ 150 mm c/c (Longitudinal
ALL FLOOR Bottom Reinforcement)
1 VARIES 6" -
LEVEL Top/ Φ12 @ 200 mm c/c (Transverse
Bottom Reinforcement)

FLOOR SLAB DETAIL

Grade of concrete = M25
Grade of rebar = Fe500

School Building P A G E | 67
STRUCTURAL ANALYSIS REPORT

S.N Length X Overall Remark

Floor Level Reinforcement
. Breadth Depth s
Layer Rebar
ALL FLOOR Top/
1 VARIES 6" Φ8 @ 150 mm c/c (BOTH WAYS) -
LEVEL Bottom

School Building P A G E | 68
STRUCTURAL ANALYSIS REPORT

2 Conclusions and recommendations

Conclusion on overall, the design has covered all its objectives. The best
possible efforts have been made to produce an appropriate design. Yet, the
designers do not guarantee the perfectionism of the successively constructed
structures. Design and construction of the structure are inter – related jobs. A
structure behaves in a manner how it has been built rather than what the
intensions is during designing. A large percentage of structural failures are
attributed due to poor quality of construction. Therefore, quality assurance is
needed in both design and construction. Detailing of steel reinforcement is an
important aspect of structural design. Poor reinforcement detailing can lead to
structural failures. Detailing plays an important role in seismic resistant design.
In seismic resistant design, actual forces experienced by the structure are
reduced and reliance is placed on the ductility of the structure. And, ductility can
be achieved by proper detailing only. For instance, care should be taken while
detailing of corners of stairs such that the steel when pulled in tension doesn’t
tend to pull out the concrete over the reinforcement. Thus, in addition to design,
attention should be paid on the amount, location and arrangement of
reinforcement to achieve ductility as well as strength.
Last but not least, this design does not supersede the application of sound
engineering judgment, professional experience and skills, and established code
of practice and guidelines. It does not refrain from using more appropriate and
approved techniques and necessary modifications incurred therefrom. The
detailed design was carried out based on the data available wherever possible
and the assumptions referring to the codes and pieces of literature where the
investigation data is not available.
Nevertheless, it is not only a good design that is enough for good
construction, appropriate construction practice, quality control and strict
adherence to the design are equally important for completing construction work
soundly. Strict quality control and due consideration of the essence of detailed
design are recommended.
The analysis and design were carried out using state-of-the-art analysis tools and
procedures with a special emphasis on the effects due to earthquakes. Under the
ultimate limit state and serviceability limit state level of earthquakes as per IS
code, a linear response spectrum analysis was performed scaled to the static
linear method.
Based on the analysis of the results, the performance of the building was
assessed using several response indicators such as natural periods, mode
shapes, base shear, story drifts, lateral displacements, and deformation and
force capacities.
The following conclusions can be drawn from this analysis:

 The building is designed to remain serviceable under frequent

earthquakes, having no or minimum cracks in the structural members.
 Story drifts are within the permissible limits under ultimate limit state and
serviceability limit state level earthquakes as per IS code.
 The building is designed to remain operational condition after a repair in
case of rare big earthquakes ensuring the life of the occupant.

School Building PAGE |

69