Objectives: In this paper, Modelling of G+5 Building with four bay is done in STAAD.Pro considering live load, dead load, to get the weight of structure. The contact between the super-structure and sub-structure are studied by modelling the soil in a simple way to capture the overall response of the system. Methods/Analysis: After modeling of building in STAAD.Pro is done, Foundation design is calculated and the obtained support reactions from STAAD.Pro are applied in PLAXIS, a finite element software to find the vertical settlement (Embedded pile foundation and isolated footing) of structure for clayey and sandy soils. Findings: Sandy soil has more bearing capacity compared to clayey soil. It is observed that clayey soil with isolated footing get more vertical settlement compared to the embedded pile, sandy soil with pile foundation get more vertical settlement compared to the isolated footing
2. Comparison of Vertical Settlement in a Multi-Storeyed Building in Different Foundations of Various Soils
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interaction problem becomes more complex when the soil, foundation and structure are to be modelled
with equal rigor. The methods used to solve the soil structure interaction problem are direct approach,
substructure approach. Direct approach is one in which the soil and structure are modelled together in a
single step secretarial for both inertial and kinematic interaction. Inertial interaction progresses in
building of its vibrations be nevolent to base shear and basement moments, which further causes
movements at the foundation comparative to permissible field. While kinematic interface propagates due
to occurrence of rigid foundation elements on or in soil affecting footing motion to diverge from
permissible‐field motions. Substructure approach is the one in which the analysis wrecked down into a
quite a few number of steps that the principal of superposition is used to separate the two primary
reasons of soil structure interaction that is inability of foundation to counterpart the free field
deformation and the effect of dynamic response of structure foundation system on the association of
supporting soil. In the investigation and strategy of engineered structures it was supposed that the
foundation of structure was fixed to a rigid underlying medium. From the last few eras, nevertheless, it
has been documented that Soil Structure Interaction (SSI) changed the response characteristics of a
structural system because of massive and stiff nature of structure and softness of soil. Numerous studies
have performed to study the effect of SSI on vibrant response of structures such as high‐rise structures,
atomic power plants and elevated highways. The subsequent section deliberates the critical review on the
SSI analysis of framed structures sustained on pile foundations.
2. METHODOLOGY (AS PER FIGURE-1 TO 5, TABLE-1 TO 3)
2.1 Winkler Approach:
The Winkler approach, also known as sub grade reaction theory, is the oldest method to predict pile
deflections and bending moments.
EP IP d4
u/d4
z + Q d2
u/dz2
= -w = - pd = - Kh ud …………. (1)
EP Ip d4
u/dz4
+ Qd2
u/dz2
+ Kh ud = 0…………….. (2)
Where, EP = pile modulus of elasticity
Q = axial load on pile
d = pile diameter
Ip = moment of inertia of pile cross section
p = pile containing soil pressure
u = lateral deflection of pile at point X along the length of the pile
Kh = soil lateral sub-grade reaction modulus
2.2 P‐‐‐‐Y Method:
The p‐y approach is used to investigate the reaction of horizontally loaded piles is basically a
modification of the basic Winkler model.
. p/pult= 0.5[y/y50]1/3
Where, pult= ultimate soil resistance per unit length coming on-to the pile
y50= 1+1/2 of the ultimate soil resistance (deflection)
The regular models of the frame consist of all modules that effect the deformability of building,
stiffness, strength and mass. All beams and columns are modeled in STAAD.Pro.
2.3 RCC Frame:
In this project, it is considered that the G+5 building with 4-bay spacing of each is 3m along X and Z
direction. The whole building is modeled in STAAD.Pro, loads considered on the building are given
below.
3. K. Hemalatha Reddy and K. Sai Kala
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Loads: The unit weight of plain concrete is taken as24 KN/m3
and reinforced concrete is taken as
25 KN/m3
.
Maximum support reaction occurs at node 13 as 858.892KN
Pile foundation and isolated footings designs were calculated.
Figure 1 Live Loads
Figure 2 Dead loads
4. Comparison of Vertical Settlement in a Multi-Storeyed Building in Different Foundations of Various Soils
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Figure 3 Plan of Pile Cap
Figure 4 Elevation of Isolated footing
#16 @ 290mm
0.7m EMBED
#12 @ 155mm
125mm CLR TYP
5. K. Hemalatha Reddy and K. Sai Kala
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Figure 5 Mesh Deformation of Clayey Soil
Table 1 Details of RCC frame
Table 2 Details of dead and live loads
Table 3 Applied loads for stress level and strength level
S. No Property Dimensions Grade of concrete
1 Plinth Beam 230 x 300 mm M30
2 Floor Beam 230 x 500 mm M30
3 Column 230 x 450 mm M30
4 Slab 150 mm M30
S. No Type Load
1 External Wall 12 KN/m
2 Internal Wall 6 KN/m
3 Slab Dead Load 4.75 KN/m2
4 Slab Live Load 2 KN/m2
Loads Considered (Service stress level)
LC
Axial
(KN)
Shear X
(KN)
Shear Z
(KN)
Moment X
(KN-m)
Moment Z
(KN-m)
11 454.793 0.000 -1.743 -0.846 0.000
12 682.189 -0.000 -2.615 -1.270 0.000
13 597.140 38.468 -2.675 -1.279 -58.533
14 597.140 -38.468 -2.675 -1.279 58.533
15 381.648 -0.000 22.478 32.788 0.000
16 812.632 -0.000 -27.827 -35.347 0.000
17 597.152 17.335 -2.675 -1.279 -26.258
Loads Considered (Strength Level)
LC
Axial
(KN)
Shear X
(KN)
Shear Z
(KN)
Moment X
(KN-m)
Moment Z
(KN-m)
11 454.793 0.000 -1.743 -0.846 0.000
12 682.189 -0.000 -2.615 -1.270 0.000
13 597.140 38.468 -2.675 -1.279 -58.533
14 597.140 -38.468 -2.675 -1.279 58.533
15 381.648 -0.000 22.478 32.788 0.000
16 812.632 -0.000 -27.827 -35.347 0.000
17 597.152 17.335 -2.675 -1.279 -26.258
6. Comparison of Vertical Settlement in a Multi-Storeyed Building in Different Foundations of Various Soils
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3. RESULTS AND DISCUSSIONS (AS PER FIGURE-6,7,8 AND TABLE-4)
Given load combinations are same for strength level and stress level so obtained strength and stress
values are equal for isolated footing.
3.1 Soil Behavior Results From PLAXIS 2D:
Fig 8 shows the graph for Effective stress for both soils (Clay and sand)in pile foundation and isolated
footing. This clearly indicates that Clayey soil is higher for both type of foundations than for sandy
soil. The effective stress of clayey soil is 23.75% more than sandy soil for isolated footing. The
effective stress of clayey soil is 23.38% more than sandy soil for pile foundation.
Fig 9 shows the graph for Vertical Displacement for both soils (Clay and sand) in pile foundation
and isolated footing. This clearly indicates that Clayey soil is higher for both type of foundations than
for sandy soil. The Vertical Displacement of clayey soil is 24.28% more than sandy soil for isolated
footing. The Vertical Displacement of clayey soil is 22.36% more than sandy soil for pile foundation.
Figure 6 Mesh Deformation of Sandy Soil
Figure 7 Effective stress for both soils (Clay and sand)
7. K. Hemalatha Reddy and K. Sai Kala
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Figure 8 Vertical Displacement of both soils (Clay and sand).
Table 4 Total Vertical displacement of Foundation with clayey and Sandy Soils
Soil Type Foundation Vertical Displacement (mm) Stresses KN/m2
Clayey
Isolated 33.02 33.93
Pile 32.46 34
Sandy
Isolated 25 25.87
Pile 25.2 26.05
4. CONCLUSIONS
In this paper, clayey soil and sandy soil in isolated footing and pile foundation are compared for
vertical displacement and effective stress respectively.
4.1 Vertical Displacement:
1. It is observed that the vertical displacement of clayey soil is 24.28% more than sandy soil for isolated
footing.
2. The vertical displacement of clayey soil is 22.36% more than sandy soil for pile foundation.
3. It is also observed that vertical displacement for isolated footing got 1.69% more than pile foundation in
clayey soil.
4. Vertical Displacement for Isolated footing is0.79% less than pile foundation in sandy soil.
4.2 Effective Stress:
1. It is observed that the effective stress of clayey soil is 23.75% more than sandy soil for isolated footing.
2. The effective stress of clayey soil is 23.38% more than sandy soil for pile foundation.
3. It is also observed that the effective stress for isolated footing got 0.25% less than pile foundation in
clayey soil.
4. Effective stress for isolated footing is0.69% less than pile foundation in sandy soil.
8. Comparison of Vertical Settlement in a Multi-Storeyed Building in Different Foundations of Various Soils
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