Analysis of Wind Load Effects on R.C Structure Resting on Flat and Sloping Ground by Using E-tabs

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 10 Issue: 06 | Jun 2023 www.irjet.net p-ISSN: 2395-0072
© 2023, IRJET | Impact Factor value: 8.226 | ISO 9001:2008 Certified Journal | Page 1134
Analysis of Wind Load Effects on R.C Structure Resting on Flat and
Sloping Ground by Using E-tabs
Ms. Khan Shaima Khan Iftekhar Khan1, Mr. Aakash Suthar 2
1Student, Master’s in Structural Engineering, L.J.I.E.T, Gujarat, India
2Assistant Professor, Structural Engineering Department, L.J.I.E.T, Gujarat, India
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Abstract - In this study, 36 models are prepared the
interaction between tallbuildingsand windonflatandsloping
ground, specifically focusingonthenorthernpartofIndiawith
high wind flow. Reinforced concrete structures of different
heights (G+5, G+10, and G+15) are analysed on both flat
terrain and slopes (0°,10°,20°, and30°)forvariouswindzones.
Wind load analyses using the e-tabssoftwareareperformedin
this paper there are 3 types of models has been done for the
different zones. The story displacement, story drift, mode
period has been also checked and result is satisfactory. Results
from software and manual calculations are compared, and
design considerations are basedon maximumobtainedvalues.
Key Words: Wind analysis, building tower, Sloping
Ground, wind load, wind analysis, high-rise structure,
deflections, wind pressure.
1. INTRODUCTION
Wind load is a critical factor in the design of structures and
requires thorough investigation to understand its effects on
buildings. Particularly, buildings constructed on hill slopes
often possess unsymmetrical characteristics. This project
focuses on conducting a comprehensive study of wind load
behavior on building frames, analysing the structural
response to wind, and assessing the impact of slope on the
structures. Structural designs aimtowithstandearthquakes,
and wind loads, maintain stability, and prevent damage.
Wind load acts as a lateral force on buildings, exerting
pressure along and across the wind direction. In [IS 875 –
(Part 3) – 2015], the basic wind speeds are specified and
categorized by zones on a map. The shape and size of a
building play a crucial role in wind analysis since wind
pressure depends primarily on the exposed area of the
building facing the wind speed.
The analysis of structuresbecomesparticularlycritical when
located on steep or sloping ground, especially in areas with
higher wind flow intensity and hilly regions. Buildings
constructed on hills using masonry with mud mortar or
cement mortar, without conforming to seismic codal
provisions, have proven to be unsafe and resulted in theloss
of life and property during earthquake ground motions.
1.1 A Building Resting on A Flat Surface
. In today's world, the expansion of cities and human
colonies is causing our agricultural fields and villages to
vanish. High-rise buildings play an important role in
minimizing wasteful land use. A tall building or structure
built for residential or commercial purposes is referred to as
a high-rise building, apartment tower, office tower,
apartment block, or block of flats.
Fig -1 Resting on A Flat Ground
1.2 An indicative R.C. Structure Resting on Inclined
Ground
Buildings resting on sloping ground present a unique set
of challenges for structural engineers. The slope of the
ground can cause uneven column heights, different soil
conditions, and increased seismic risk. These challenges
must be carefully considered in the design and construction
of the building to ensure its safety and stability.

Fig -2 Resting on Inclined Sloping Ground
1.3 Objectives
The objectives of the analysis of wind load effects on an
R.C. structure resting on flat and slopinggroundusingE-tabs
are as follows:
Evaluate wind load distribution: Determine the
distribution of wind loads on the structure considering both
flat and sloping ground conditions.
Compare effects on the flat and sloping ground: Analyse
and compare the effects of wind loads on the structurewhen
it is resting on flat ground versus sloping ground.
Study structural behaviour: Investigate the structural
behaviour of the R.C. structure under wind loads, including
deflections, bending moments, shear forces, and support
reactions.
Assess structural stability: Evaluate the stability of the
structure under wind loads, considering both overall
stability and individual member stability.
Optimize design: Identify areas of improvement in the
structural design to enhance the resistance against wind
loads.
Validate design codes: Compare the results obtained from
the analysis with the provisions specified in relevant design
codes and standards.
Provide recommendations: Based on the analysis results,
offer recommendations for improving the structural design,
construction techniques, or site selection to enhance the
wind resistance of the R.C. structure on both flat and sloping
ground.
Overall, the study aims to provide valuable insights into the
analysis of wind load effects on buildings restingonbothflat
and sloping ground, with a focus on wind zones and the use
of ETABS software for design purposes.
2. LITERATURE REVIEW
BD Yadav1*,NileshChoudhary1,JaydevKumarMahato2
and Nitin Kumar2, “study the effects of various wind
loadings in high rise rc-framed structuresinzone–v”Inbrief
it is found that: Wind loading, and seismic loading are two
crucial factors in the design of high-rise buildings to ensure
their stability and structural integrity. Let us deeper into
each aspect and discuss the relevant provisionssuggested in
the Indian Standards (IS).
Prof. D.N. Kakde1, Shaikh Mohd. Kasheef, “influence of
slope angle variation on the structures resting on sloping
ground subjected to heavy winds.” The research study
focused on evaluating the structural performance of high-
rise structures in the northern part of India, where wind
flow is significantly higher. These structures were further
complicated by being constructed on inclined portions of
hilly regions. The study aimed to specifically examine the
effects of heavy wind loads on such structures.
Naveen Suthar, Pradeep K. Goyal, “comparison of the
response of building against wind load as per wind codes [is
875 – (part 3) – 1987] and [is 875 – (part 3) – 2015].” In
brief it is found that: The research paper presented a
comparison of wind loads for a G+11 building using two
different wind loading codes: the old code [IS: 875 – (Part 3)
– 1987] and the new code [IS: 875 – (Part 3) – 2015]. The
comparison focused on the wind loads calculated using the
static method for zone 4 with terrain category 3. This
comparison allowed them to assess the differences in the
wind load calculations and understand how the changes in
the code provisions affected the structural response.
B. Shobha1, Dr.H. SudarsanaRao2, Dr. Vaishali.G.
Ghorpade, “effect of wind load on low, medium, high-rise
buildings in different terrain categories.” In this study, the
focus is on assessing the response of tall buildings to wind
loads, specifically considering both"alongwind"and"across
wind" vibrations caused by wind flow. While modern tall
buildings are designed to meet lateral drift requirements,
excessive oscillations can still occur during windstorms,
which can pose threats to the structure's integrity andcause
discomfort to occupants. Therefore, accuratelyassessingthe
motion of tall buildings under wind loads is crucial toensure
their serviceability.
K. Surender Kumar a, N. Lingeshwaran b Syed Hamim
Jeelani, “ANALYSIS OF RESIDENTIAL BUILDING WITH
STAAD. PRO & ETABS.” This paper focuses on thedesignand
analysis of a multi-story building with the aim of achieving
efficiency and long-term durability. Multi-story buildings
offer the advantage of increased floor area without the need
for expanding the land area, resulting in cost savings and
optimized land utilization. The primary objective of the
study is to develop an effective design analysis methodology
that encompasses various aspects such as load cases, load

combinations, support reactions, and the reinforcement of
columns and beams.
3. METHODOLOGY
The analysis and design of an RCC structurerestingonflator
sloping ground using ETABS software typically involvethe3
different types of story building is possible for Analysis of
Wind Load Effects on R.C Structure Resting on at
0°,10°,20°,30° Sloping Ground. These steps require a good
understanding of IS codes (Indian Standard codes) and
fundamental structural concepts. To validate and compare
the results, a total of 36 models were created.
Analysis of Wind Load Effects on R.C
Structure Resting on at 0°,10°,20°,30°
Sloping Ground
(G+5) Building at
different Basic Wind
Speed Zone
(G+10) Building at
Speed Zone
(G+15) Building at
Speed Zone
0° 10° 20° 30°
Zone3 Zone3 Zone3 Zone3
0° 10° 20° 30°
0° 10° 20° 30°
Fig -3 Flow Chart of models
3.1 Software of analysis
ETABS is a powerful and versatile software that can be used
to accurately calculate wind loads on buildings according to
Indian standards.Thesoftware'sfeaturesmakeit well-suited
for a variety of wind load analysis applications,includingthe
design of new buildings and the evaluation of existing
buildings for wind safety.
These features include the ability to:
• Calculate wind loads based on the terrain category
and height of the building.
• Account for the effects of wind gusts and vortex
shedding.
• Calculate wind-induced uplift forces.
• Generate a variety of reports that can be used to
document wind load calculations.
 ETABS is a commercial software, so there is a cost
associated with using it.
 The software can be complex to learn and use, so it
is important to have some training before using it
for wind load analysis.
3.2 Modelling
To study the seismic behavior of RCC structure, different
cases have been defined and their comparative graphs for
these cases have been plotted. A typical RCC building will be
designed and analysed for dead load, live load, wind load.
i. Seismic zone, Z (IS 1893: 2002, clause 6.4.2,table 2)
ii. Response reduction factor, R (IS 1893: 2002, clause
6.4.2, table 7)
iii. Importance factor, I (IS 1893: 2002, clause 6.4.2,
table 6)
iv. Soil type (IS 1893: 2002, clause 6.4.5, page 16)
Table -1: Modelling Details for RCC Structure
PARAMETERS DETAILS
Number of stories (G+5), (G+10), (G+15)
Type of structure R.C. Structure
Story to Story height 3m
Ground story height 3m
Grade of concrete M30 for Column and Slab &
M30 for Beam
Thickness of slab 150mm
Thickness of slab 230mm
Beam size 400mmX400mm
Column size 450mmX600mm
Density For concrete
25KN/m
For Brick wall 19 KN/m
Basic wind Speed Zone Zone3, Zone4,
Zone5
Degree of Slope 0°,10°,20°,30°

Fig - 4 Top View of Typical Structure
Fig – 5 Plain Ground Structure
Fig - 6 Story G+10º Sloping Ground
Fig – 7 G+10 Story 10º Sloping Ground
Fig – 8 G+15 Story 10º Sloping Ground

Fig – 9 G+5 Story At 0º
4. OBSERVATIONS
There are 3 major types of models is analysed of different
heights (G+5, G+10, and G+15) on both flat terrain and
slopes (0°,10°,20°, and 30°) with different wind zones.
4.1 Story Displacement: - The permissible limit for story
displacement is 0.004 times the story height. Therefore, the
story displacement values in the table are within the
permissible limit.
The X and Y direction values are the same in the table
because the building is assumed to be symmetrical in both
directions. This means that the wind load is applied equally
in both directions, and the stiffness of the building is the
same in both directions.
4.1 Story Displacement: - The permissible limitforstory
displacement is 0.004 times the story height.
Chart 1: -Story Displacement for three Models
4.2 Story Drift: - The permissible limit of story drift
depends on the type of structure and the applicable
building code. In India, the permissible limit of story
drift for RC structures is 0.004 times the story height.
The values given in the table are within the permissible
limit.
Chart 2: -Story Drift for three Models
4.3 Mode Period: - The permissible limit of mode period
depends on the type of structure and the applicable
building code. In India, the permissible limit of mode
period for RC structures is 0.15 seconds. The values
given in the table are within the permissible limit.
The values in both X and Y directions are the same because
the building is assumed to be symmetrical inbothdirections.
This means that the wind load is applied equally in both
directions, and the stiffness of the building is the same in
both directions.

Chart 3: -Mode Period for three Models
5. CONCLUSIONS
Table -2: A table that summarizes wind characteristics
in various zones: -
Wind
Zone
Table 1 Table 2
Zone 3 Story drift increases
with number of
stories and slope.
Story displacement
increases with
number of stories
and slope. Mode
period increases
with number of
stories and slope.
Story drift increases
with number of stories.
Story displacement
increases with number
of stories. Mode period
decreases with number
of stories.
with number of
stories and slope.
Story displacement
increases with
number of stories
and slope. Mode
period increases
with number of
stories and slope.
Story displacement
of stories.
with number of
stories and slope.
Story displacement
increases with
number of stories
and slope. Mode
period increases
with number of
stories and slope.
Story displacement
of stories.
In all three wind zones, story drift and story displacement
increase with the number of stories and slope. This is
because the taller the building, the more it will sway in the
wind or under seismic loading. The slope of the ground also
has an effect, as a sloping ground will cause the building to
sway more than a level ground.
In Zone 3 and Zone 4, mode period increases with the
number of stories and slope. This is because a taller building
has more mass, which will tend to dampen the swaying
motion. However, in Zone 5, mode perioddecreaseswith the
number of stories. This is because the higher wind speeds in
Zone 5 require a shorter modeperiodtopreventthebuilding
from oscillating too much.
1. The structure on sloping ground exhibits a higher
maximum displacement, which can lead to critical
situations compared to structures on flat ground.
2. The mode shape analysis reveals that the 15-storey
structure has the longest period at both the top and
bottom stories.
3. The tables show that story drift,storydisplacement,
and mode period all increase with the number of
stories and slope. However, mode period decreases
with the number of stories. This is because a taller
building has more mass, which will tend to dampen
the swaying motion.
4. The base shear is greater in the X-direction than in
the Y-direction for structures on sloping ground.
5. The mode period decreases as the slope angle
increases.
6. The maximum storydisplacementisobservedinthe
structure with a 10º slope.
7. The displacement is higher at the top story
compared to the bottom story in all other models,
both in the X-direction and Y-direction.
8. The maximum story drift occurs in the structure
with a 10º slope in all models.
REFERENCES
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N. (2023). Study The Effects of Various Wind
Loadings in High Rise Rc-Framed Structures In
Zone–V. Journal of Civil Engineering Research &
Technology. SRC/JCERT-140. DOI:
org/10.47363/JCERT/2023 (5), 139, 2-6.
[2] Kakde, D. N., & Kasheef,S.M. (2020).INFLUENCEOF
SLOPE ANGLE VARIATION ON THE STRUCTURES
RESTING ON SLOPING GROUND SUBJECTED TO

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of response of building against wind load as per
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Analysis of Wind Load Effects on R.C Structure Resting on Flat and Sloping Ground by Using E-tabs