seismic analysis of structures presentation

1. SEISMIC ANALYSIS OF SYMMETRIC AND
UNSYMMETRIC BUILDINGS IN PLAN.
Dr. V.P.S.S.M’s
PADMABHOOSHAN VASANTRAODADA PATIL
INSTITUTE OF TECHNOLOGY, BUDHGAON.
Roll no. Name
36 Sourabh Pradipkumar Patil.
37 Shreejay Suresh mane.
66 Sagar Gyanba Lokare.
45 Vijay Vishnu Khatake.
69 Prajwal Sanjay Parashkar.
PRESENTED BY -
PROJECT GUIDE –
MR.A.A.KUSANALE SIR

2. ABSTRACT
• Structural analysis is mainly used for finding out the behaviour of a structure
when subjected to some loading.
• Earthquakes, in which many reinforced concrete structures have been
severely damaged or collapsed, indicated the need for evaluate and increase
the Seismic performance of buildings.
• Buildings with symmetry and asymmetry in plan, geometry, strength, stiffness.
• Structural design of buildings for seismic loads is very important for structural
safety during major ground motions.
• Analysis of major earthquakes have shown that the irregular distribution of
mass, stiffness and strengths i.e. unsymmetrical buildings may cause serious
damage in structural systems.

3. INTRODUCTION
• Earthquake is a natural disaster occurred due to sudden and transient
motion of the earth’s surface.
• It is very important to modify the seismic behaviour of existing structures.
• Seismological data from many earthquakes were collected and analysed to
make seismic zones and understand the phenomena of earthquakes.
• To study the seismic effects of infill on symmetrical and asymmetrical
models, seismic analysis is performed using linear dynamic (Response
spectrum method), nonlinear static methods (Pushover analysis), equivalent
static analysis and Time History Analysis (Non-linear dynamic analysis).

4. • Loads are considered for analysis –
a) Dead Load (IS 875 Part 1:1987)
b) Live Load (IS 875 Part 2:1987)
c) Earthquake Loads by Seismic Coefficient Method (IS 1893 Part I:2002)
• Structural design of buildings for seismic loads is very important for structural
safety during earthquakes.
• In IS 1893 – 2002 (Part 1) parameters mentioned below to evaluate seismic
output parameters in form of design are seismic coefficient, base shear,
storey shear and mass participation factor.

5. LITERATURE REVIEW
1. Seismic Analysis Of asymmetry In Plan Buildings(Dr. Z.
Ladrinovic and R. J. Folic) (2008) –
• In this paper, author explained Buildings with an asymmetric
distribution of stiffness and strength in plan undergo coupled lateral
and torsional motions during earthquakes.
2. Desale Sachin , Jondhale Rohini , Sabale Ganesh (2011) -
• The aim of this paper is to study the seismic behavior of building of
symmetrical and asymmetrical structure using STAAD Pro.
• The author explains that the seismic rehabilitation of concrete structures in
high seismicity areas is a matter of growing concern, so damage qualification
of buildings must be identified and an acceptable level of safety must be
determined.

6. 3. Dr. S. D. Bhole, Sabahat J. Ansari(2015) –
• Three building models for L-shaped and T-shaped building are considered
for study, which are constructed on medium soil in seismic zone Ш of India
(as per IS: 1893-2002[9]), one symmetric and 3 asymmetric in stiffness
distribution.
4. Sayantika Saha(2015) –
• In this paper the effort is made to study the effect of eccentricity between
centre of mass (CM) and centre of stiffness (CR) and the effect of stiffness
of shear walls on the performance of the symmetric and unsymmetric
buildings during earthquake.
5. B K Raghuprasad, Vinay S, Amarnath.(2016) –
• In this Paper, A 11 storey building with eccentricity same on all the floors
(uniform eccentricity) and the other with eccentricity varying over the floors
have been subjected to EL-Centro 1940 N-S component ground motion input
and the responses like spectral displacement, spectral acceleration, spectral
velocity are obtained is there considerable difference between the two.

7. • The effect of sloping ground on columns which have varying height are
studied, the plan layout considered is same for hilly terrain and plains .
6. Non linear response of two way asymmetrical multi storey
building under bi-axial excitation. (Nishant K. Kumar, Rajul K.
Gajjar.)(2014) –
• Time history analysis has been carried out using SAP2000 after validating a
preliminary model.
• Three building plans, with eccentricity along each of x and z directions in plan
and a third with eccentricity in both the orthogonal direction, have been
studied.
7. Seismic analysis of structure (T. k. Datta) (2010):
• The author studied of collected seismological data and it has helped in the
rational design of structures to withstand earthquakes.
• The author has used Modal Analysis Using the Substructure Technique to
analyse the seismic forces on frame of building.

8. To study the comparison between symmetrical and unsymmetrical
building subjected to seismic forces.
AIM :-
OBJECTIVES :-
1. To study the seismic parameters of building structure.
2. Defining a problem statement for symmetric buildings.
3. Creating a model of symmetric building on software and analysis of symmetric
building subjected to seismic forces.
4. Defining a problem statement for unsymmetrical building.
5. Creating a model of unsymmetrical building on softwareand analysis of
unsymmetrical building subjected to seismic forces.
6. Comparison between symmetrical and unsymmetrical building subjected to
earthquake.

9. PROPOSED WORK
 Parameters considered while analyzing the symmetrical and unsymmetrical
buildings :-
 Type of earthquake excitations.
 Period of vibration of structure.
 Importance of structure.
 Type of seismic zone.
 Materials used in construction.
 Structural symmetry.
For this we have to define a sample problem and apply various seismic parameters
on the sample building with the help of software .

10. PROPOSED METHODOLOGY
METHODS OF
STRUCTURAL
ANALYSIS.
Equivalent
static analysis.
Response
spectrum
analysis.
Non-linear
static analysis.
Time History
Analysis

11. EQUIVALENT STATIC ANALYSIS
 Equivalent static analysis can work well for low to medium-rise buildings.
 This method is to be done with an estimation of base shear load and its distribution
on each story calculated by using formulas given in the code.
 Equivalent static analysis is restricted only to a single mode of vibration of the
structure.
 Then the displacement demand of model must be checked with code limitation.
RESPONSE SPECTRUM ANALYSIS.
 This method is favored by earthquake engineers for a number of reasons –
1. It allows a clear understanding of the contributions of different modes of vibration to
the overall seismic response of structures.
2. It offers a simplified method for finding the design forces for the members of
structures for earthquake forces.
3. It is also useful in the approximate evaluation of the reliability and safety of
structures under earthquake forces.

12. NON-LINEAR STATIC ANALYSIS
1. Non-linear static analysis is also referred as pushover analysis. It is the method used
to determine the ultimate load and deflection capability of the structure.
2. Local non linear effects such as flexural hinge at the member joints , are modeled
and the structure is deformed or pushed until enough to develop a collapse
mechanism or until the plastic deformation limit is reached.
3. The pushover concept can be illustrated easily with cantilever beam.
TIME HISTORY ANALYSIS
 It is an analysis of the dynamic response of the structure at each increment of time,
when its base is subjected to a specific ground motion time history.
 The steps involved in time history analysis are as follows:
• Calculation of Modal matrix and effective force vector
• Obtaining of Displacement response in normal and physical coordinate
• Calculation of maximum response.

13. PROBLEM STATEMENT
SYMMETRICAL BUILDING :-
Type of frame: SMRF
Seismic zone: 2
Number of story: 8(G+7)
Floor height: 3.2m
Spacing between frames-
4M along X-Axis
4m along Y-Axis
Materials Used: M20 grade concrete,
Fe 415 grade steel.
Density of Concrete:25 kg/m3.
Type of soil: Hard.
Live Load: 6 KN/m2.
DIFFERENT SHAPES OF BUILDIG
TAKEN FOR ANALYASIS:
Rectangular
C
Plus
L
T
I

14. RECTANGULAR STRUCTURE
 Beam-
0.35m x 0.65m (1st, 2nd floor)
0.3m x 0.65m (Remaining Floors.)
 Column-
0.6m x 0.6m (1st, 2nd, 3rd floor)
0.5m x 0.5m (4th, 5th, 6th floor)
0.4m x 0.4m (7th, 8th floor)
 Beam-
0.23m x 0.4m (All Floors)
 Column-
0.6m x 0.55m (1st , 2nd floor)
0.65m x 0.55m (3rd floor)
0.55m x 0.45m (4th, 5th, 6th floor)
0.45m x 0.35m (7th , 8th floor)
C SHAPED STRUCTURE

15. PLUS SHAPED STRUCTURE
 Beam-
0.23m x 0.4m (All Floors)
 Column-
0.6m x 0.55m (1st , 2nd floor)
0.65m x 0.55m (3rd floor)
0.55m x 0.45m (4th, 5th, 6th floor)
0.45m x 0.35m (7th , 8th floor)
 Beam-
0.23m x 0.4m
 Column-
0.6m x 0.55m (1st , 2nd floor)
0.65m x 0.55m (3rd floor)
0.55m x 0.45m (4th, 5th, 6th floor)
0.45m x 0.35m (7th , 8th floor)
L SHAPED STRUCTURE

16. T SHAPED STRUCTURES
 Beam-
0.23m x 0.4m
 Column-
0.6m x 0.55m (1st , 2nd floor)
0.65m x 0.55m (3rd floor)
0.55m x 0.45m (4th, 5th, 6th floor)
0.45m x 0.35m (7th , 8th floor)
 Beam-
0.23m x 0.4m
 Column-
0.6m x 0.55m (1st , 2nd floor)
0.65m x 0.55m (3rd floor)
0.55m x 0.45m (4th, 5th, 6th
floor)
0.45m x 0.35m (7th , 8th floor)
I SHAPED STRUCTURES

17. FLOOR Rectangular Shape Building
STIFFNESS
Other Shape Building
STIFFNESS
1 349534.1 363760.9
2 1414882 1472471
3 1414882 1472471
4 682331.4 683013.7
5 682331.4 683013.7
6 682331.4 683013.7
7 279482.9 251780.3
8 279482.9 251780.3
FLOOR Rectangular Shape Building
MASS ( IN KN )
Other Shape Building
MASS ( IN KN )
1 2925.245 2920.908
2 2284.954 2297.284
3 2284.954 2297.284
4 2248.02 2249.42
5 2196.052 2205.896
6 2196.052 2205.896
7 2174.796 2170.832
8 1926.792 1932.368
Floor wise mass and stiffness of structure
Table no. 1: Masses for rectangular and other shaped buildings.
Table no. 2: Stiffness For Rectangular And Other Shaped Buildings.

18. FASCILITIES AVAILABLE
FOLLOWING FASCILITIES ARE AVAILABLE IN
COLLEGE FOR THE PROJECT WORK :-
1. Central library.
2. Departmental library.
3. Computer lab with internet connection.
4. Computer lab
5. Research paper and journals.

19. SCHEDULE OF
PROJECT.
SEM 1.
Collection of data.
Study of earthquake related
parameters.
Problem statement for both type of
buildings.
Submission of synopsis.
SEM 2.
Software model of symmetrical and
unsymmetrical buildings.
Analysis of both the buildings
subjected to seismic forces.
Comparison between symmetrical
and unsymmetrical building.
Submission of project.

20. REFFERANCES
1. Improved seismic design of structural frames by optimization of equivalent
lateral load pattern .- M. Shahrouzi, A.A. Rahemi.
2. Dorde Ladinovic, ― Nonlinear seismic analysis of asymmetric in plan
building‖ by FACTA UNIVERSITATIS: Architecture and Civil Engineering Vol.
6, No 1, pp. 25 – 35, 2008
3. Raghu Prasad B K and Saibaba S, ―Influence of shape in plan of building
on the inelastic earthquake response‖, Proceeding of 8th European
conference on earthquake engineering, Libson, Portugal, pp 17-24,
September 7-12,1986.
4. Pralobh S. Gaikwad and Kanhaiya K. Tolani, Review Paper on Dynamic
Analysis of Building , International Journal of Current Engineering and
Technology E-ISSN 2277 – 4106, P-ISSN 2347 – 5161.
5. IS 1893: 2002, “Indian Standard criteria for earthquake resistant design of
structures, Part 1 General provisions and buildings”, Draft of Fifth Revision,
Bureau of Indian Standards, New Delhi, 2002.