I JSRD - I nternational Jour nal for Scientifi c Re se arch & Deve lopment| Vol. 3, I ss ue 11, 201 6 | I SSN ( onli ne): 2321-0 613 All rights reserved by www.ijsrd.com389 Linear Static Analysis of Regular Space Frame with & without Fixed Base Ms. Akshaya Ghalimath 1 Mr. Mantesh A.Hatti 2 Ms. Sheetal More 3 Ms. Chaitrali Jamadar 4 1,2,3,4 Department of CivilEngineering 1,2,3,4 A.G. Patil Institutes, Solapur, Solapur University Abstract—Due to present increase in the world population people in this world tends to occupy available location present in any zone, which also includes zones falling in the high seismic zone categories. Commonly designers consider the building to be fixed at their bases. Flexibility of the soil causes the decrease in stiffness resulting increasing in the natural period of the structure. Such increases in the natural periods, changes the seismic response of structure hence it may be an important issue for design consideration. The present st udy provides systematic guideline for determining the natural periods of frame buildings due to the effect of soil-flexibility and identification of spring stiffness for linear building story and various influential parameters such as period, displacement, base shear and column forces have identified for both fixed and flexible base has to be studied for bare frame for all types of soils. Key words:Bare Frame, Fixed Base, Flexible Base, Base Shear, Period, Displacement, Axial Forces In Column I.I NTRODUCTIONPresently and majority existing of reinforced cement concrete structure has been a tremendous increase in the amount of tall stories in modern localities and the structures do not need the current seismic requirement as they are primarily designed for gravity loads only. Since the structure being tall and slender are subjected to seismic and wind load, if the structure is not stiff enough to resist the loads and vibration cause. Therefore it is important for these structures to resist lateral forces along with vertical forces. As waves from an earthquake a reach a structure, they produce motion in the structure. T his motion depends on the structure vibration characteristics and the layout of the structure. For the structure to reach to the motion, it needs to overcome its own inertia force, which results in an interaction between the structure and the soil. The extent to which the structural response changes the characteristics of earthquake motions observe at the foundation level depends on the relative mass and stiffness properties of the soil and the structure. Thus the physical properties of the foundation medium are an important factor in the earthquake response of the structure supported on it. The process in which the response of soil influences the motion of the structure and the motion of the structure influence the response of the soil is termed as soil structure interaction. In the analysis work one model of R.C.C. Space Frame G+ 10 floors are made to know the realistic behavior of building during earthquake. A.Bare Frame: The in-plane stiffness of masonry infill wall is not taken into account in bare frame. Bare frame will deflect under horizontal loads by bending in columns and beams .Non- structural components such as masonry that are subjected to seismic forces are not normally within the design scope of the structural engineer, whose responsibility is to provide the seismic safety of the building. Fig. 1:Bare Frame II.THEORETICAL FORMULATIONA.Objective The main objective of this work is to carry out the effect of bases, types of soil on the seismic behavior of R.C.C. building with linear static analysis method. B.Methods of Seismic Analysis Following Flow chart shows seismic analysis methods used for Seismic evaluation: Fig. 2: Seismic Analysis Methods 1)Linear Static Analysis Equivalent static analysis is the indirect method of considering the effect of ground motion and there is incorporation of dynamic properties of the structure in terms of fundamental period, response reduction factor, soil type, seismic zone and importance factor. Equivalent static analysis were carried out for all the models under the action of Dead load (DL), Live load (LL) and earthquake load (EQ) for different load combination as per IS 1893-2002. This method is limited to regular type of structure whose response is governed by first mode of vibration. As per IS 1893-2002 regular structure up to 40m in height in zone IV and V and up to 90m in zone II and III can be analyzed by Time History and Response Spectrum analysis. 2)SMRF: Special Moment-Resisting Frame, It is a moment- resisting frame specially detailed to provide ductile behavior and comply with the requirements given in IS 4326 or IS13920 or SP6.For the analysis and design purpose one model has been considered namely as bare frame (S.M.R.F frame).
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Linear Static Analysis of Regular Space Frame with & Without Fixed Base
Due to present increase in the world population people in this world tends to occupy available location present in any zone, which also includes zones falling in the high seismic zone categories. Commonly designers consider the building to be fixed at their bases. Flexibility of the soil causes the decrease in stiffness resulting increasing in the natural period of the structure. Such increases in the natural periods, changes the seismic response of structure hence it may be an important issue for design consideration. The present study provides systematic guideline for determining the natural periods of frame buildings due to the effect of soil-flexibility and identification of spring stiffness for linear building story and various influential parameters such as period, displacement, base shear and column forces have identified for both fixed and flexible base has to be studied for bare frame for all types of soils.
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7/21/2019 Linear Static Analysis of Regular Space Frame with & Without Fixed Base
1,2,3,4Department of Civil Engineering1,2,3,4A.G. Patil Institutes, Solapur, Solapur University
Abstract — Due to present increase in the world population
people in this world tends to occupy available location
present in any zone, which also includes zones falling in the
high seismic zone categories. Commonly designers considerthe building to be fixed at their bases. Flexibility of the soil
causes the decrease in stiffness resulting increasing in the
natural period of the structure. Such increases in the natural
periods, changes the seismic response of structure hence it
may be an important issue for design consideration. The
present study provides systematic guideline for determining
the natural periods of frame buildings due to the effect of
soil-flexibility and identification of spring stiffness for linear
building story and various influential parameters such as
period, displacement, base shear and column forces haveidentified for both fixed and flexible base has to be studiedfor bare frame for all types of soils.
Key words: Bare Frame, Fixed Base, Flexible Base, Base
Shear, Period, Displacement, Axial Forces In Column
I. I NTRODUCTION
Presently and majority existing of reinforced cement
concrete structure has been a tremendous increase in the
amount of tall stories in modern localities and the structures
do not need the current seismic requirement as they are
primarily designed for gravity loads only. Since the structure
being tall and slender are subjected to seismic and wind
load, if the structure is not stiff enough to resist the loadsand vibration cause. Therefore it is important for these
structures to resist lateral forces along with vertical forces.
As waves from an earthquake a reach a structure, they
produce motion in the structure. This motion depends on the
structure vibration characteristics and the layout of the
structure. For the structure to reach to the motion, it needs to
overcome its own inertia force, which results in an
interaction between the structure and the soil. The extent to
which the structural response changes the characteristics ofearthquake motions observe at the foundation level depends
on the relative mass and stiffness properties of the soil and
the structure. Thus the physical properties of the foundation
medium are an important factor in the earthquake responseof the structure supported on it. The process in which the
response of soil influences the motion of the structure and
the motion of the structure influence the response of the soil
is termed as soil structure interaction.
In the analysis work one model of R.C.C. Space
Frame G+ 10 floors are made to know the realistic behavior
of building during earthquake.
A. Bare Frame:
The in-plane stiffness of masonry infill wall is not taken into
account in bare frame. Bare frame will deflect under
horizontal loads by bending in columns and beams .Non-
structural components such as masonry that are subjected toseismic forces are not normally within the design scope of
the structural engineer, whose responsibility is to provide
the seismic safety of the building.
Fig. 1: Bare Frame
II. THEORETICAL FORMULATION
A. Objective
The main objective of this work is to carry out the effect of bases, types of soil on the seismic behavior of R.C.C.
building with linear static analysis method.
B. Methods of Seismic Analysis
Following Flow chart shows seismic analysis methods used
for Seismic evaluation:
Fig. 2: Seismic Analysis Methods
1) Linear Static Analysis
Equivalent static analysis is the indirect method of
considering the effect of ground motion and there is
incorporation of dynamic properties of the structure in terms
of fundamental period, response reduction factor, soil type,
seismic zone and importance factor. Equivalent static
analysis were carried out for all the models under the action
of Dead load (DL), Live load (LL) and earthquake load
(EQ) for different load combination as per IS 1893-2002.This method is limited to regular type of structure whose
response is governed by first mode of vibration. As per IS
1893-2002 regular structure up to 40m in height in zone IV
and V and up to 90m in zone II and III can be analyzed by
Time History and Response Spectrum analysis.
2) SMRF:Special Moment-Resisting Frame, It is a moment- resisting
frame specially detailed to provide ductile behavior and
comply with the requirements given in IS 4326 or IS13920
or SP6.For the analysis and design purpose one model has
been considered namely as bare frame (S.M.R.F frame).
7/21/2019 Linear Static Analysis of Regular Space Frame with & Without Fixed Base