static linear and non linear (pushover) analysis of rc building on sloping grounds on medium soils...

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International Journal of Civil Engineering and Technology (IJCIET)Volume 8, Issue 1, January 2017, pp.

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ISSN Print: 0976-6308 and ISSN Online: 0976

© IAEME Publication Scopus

STATIC LINEAR AND NO

ANALYSIS OF RC BUILD

ON MEDIUM SOILS

PG Student, Civil Engineering Department, K L University, A.P, India

Professor, Civil Engineering Department, K L University, A.P, India

ABSTRACT

OBJECTIVE: This paper Deals with the

to uneven constructions undergo extra harm than their common counterpart

seismic design codes, & limitation

compulsory. METHODS/ANALYSIS

within twist influence ability,

Altitude irregularity has been observed in the direction of reason story failure due to non

distribute of demand-to-supply ratios

resting on the additional hand, reason non

columns. In this paper the structure chosen for study is a

building. The building which

mathematical models for the same are generated in

structural fundamentals, M40 G

be rigid. Seismic loads were considere

a 4 to7 storey RC structure with typical ground slope choosing

building that which produce less torsion effect for set

configuration in horizontal &

also used that which resist during earthquake and building that which produce less torsion effect

for setback - step back with irregular

Key words: Setback-Step Back,

Base Shear, Target Displacement,

Cite this Article: N.V. Mohanakrishna and CH. Hanumantha Rao, Static Linear and Non Linear

(Pushover) Analysis of RC Building On Sloping Grounds On Medium Soils In Different Zones

International Journal of Civil Engineering and Technology

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International Journal of Civil Engineering and Technology (IJCIET) , pp. 811–820, Article ID: IJCIET_08_01_095

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6308 and ISSN Online: 0976-6316

Scopus Indexed

STATIC LINEAR AND NON LINEAR (PUSHOVER)

ANALYSIS OF RC BUILDING ON SLOPING GROUNDS

ON MEDIUM SOILS IN DIFFERENT ZONES

N.V. Mohanakrishna


CH. Hanumantha Rao


This paper Deals with the seismic activity field investigation

undergo extra harm than their common counterpart

limitations on top of sudden changes within mass &

METHODS/ANALYSIS: Irregularity within sizes pressures sharing about rigidity, &

twist influence ability, as mass irregularity is likely to pressure compulsory require

ltitude irregularity has been observed in the direction of reason story failure due to non

supply ratios the length about length of the elevation. Plan irregularity,

resting on the additional hand, reason non-uniform demand-to-capacity ratios bounded by the

columns. In this paper the structure chosen for study is a 4 to 7 storey commercial complex

which is located in seismic zone III, IV, & V on Medium soil sites

mathematical models for the same are generated in ETABS software

0 Grade of material is used. The floor Diaphragms are unspecified to

eismic loads were considered acting along either of the 2 major directions. Using ETABS

storey RC structure with typical ground slope choosing angle range

building that which produce less torsion effect for set-back & step

vertical direction is modeled and analyzed. “And isolated bearing is


step back with irregular configuration.

Back, Static Linear Analysis, Static Nonlinear (PUSHOVER

Displacement, Hinge Status, Isolated Bearing.

N.V. Mohanakrishna and CH. Hanumantha Rao, Static Linear and Non Linear

(Pushover) Analysis of RC Building On Sloping Grounds On Medium Soils In Different Zones

International Journal of Civil Engineering and Technology, 8(1), 2017, pp.


[email protected]

&IType=1

N LINEAR (PUSHOVER)

SLOPING GROUNDS

IN DIFFERENT ZONES



c activity field investigations often verify so as

undergo extra harm than their common counterparts. This is known in

s on top of sudden changes within mass & rigidity are

sharing about rigidity, &

s mass irregularity is likely to pressure compulsory required.

ltitude irregularity has been observed in the direction of reason story failure due to non-uniform

e elevation. Plan irregularity,

capacity ratios bounded by the

4 to 7 storey commercial complex

on Medium soil sites. 3D

ETABS software. FINDINGS: For all

iaphragms are unspecified to

directions. Using ETABS

angle range between 00 and 40

0

back & step-back with irregular

vertical direction is modeled and analyzed. “And isolated bearing is


PUSHOVER) Analysis,

N.V. Mohanakrishna and CH. Hanumantha Rao, Static Linear and Non Linear

(Pushover) Analysis of RC Building On Sloping Grounds On Medium Soils In Different Zones.

, 8(1), 2017, pp. 811–820.


N.V. Mohanakrishna and CH. Hanumantha Rao

http://www.iaeme.com/IJCIET/index.asp 812 [email protected]

1. INTRODUCTION

In many parts of India it is a regular practice to construct building on hill slopes, whether there is a natural

hill sloping terrain. The building on the sloping terrain undergoes severe torsion under earthquake

hazardous excitation due to significant variation in the elevation of ground floor columns. To make the

decision on the safety, adequacy or to assess the actual behavior of the structures, sophisticated analytical

methods are needed. Static Non linear (Pushover) Analysis has become a popular method during the last

some decades for the seismic assessment of structure. Pushover (Non Linear) Analysis preserves

performed as force controlled or displacement-controlled. During force-controlled Pushover (Non Linear)

method, Full Load arrangement is used while précised, which is force controlled method, must survive to

use at what time the Load is previously recognized. Also, in force-controlled pushover (Non Linear)

method a few mathematical troubles so as to pressure exactness about outcome take place as Aim

displacement perhaps be linked by means of a extremely minute constructive (positive) otherwise yet a

unconstructive (Negative) Horizontal rigidity for the cause that about development of techniques & P-∆

things. It is the chosen tool for evaluation of seismic presentation of structures by the main rehabilitation

guiding principles and codes for the reason so as to it is theoretically and computationally easy & allows

tracing series about elastic & breakdown on top of part & structural phase fine as growth about the whole

ability curve about structure. In this isolated bearings are used in which the seismic separation system is to

decouple Building construction starting the destructive mechanism about seismic activity entered

movement that is, on the way to avoid super-structure about Building starting interesting i.e., fascinating

seismic activity power. The whole super-structure have to be supported on divide isolators whose vibrant

characteristics be selected towards separate Ground movement. A few separators are too designed to merge

considerable vibration. Displacement & elasticity are determined next to the level of the isolation

strategies, & super-structure behaves extremely a large amount similar to a rigid body.

The equivalent static method doesn’t consider the ir-regular effects in the building and since it depends

only on empirical formula the results obtained will be abnormal in comparison to response spectrum

method. By Ravikumar C M1, Babu Narayan K, Sujith, Venkat Reddy D1.The performance of STEP back

building during seismic excitation could prove more. Vulnerable than other configurations of buildings.

B.G. Birajdar1, S.S. Nalawade2. The natural period decreases as the stiffness of the building increases and

thereby leading to increase in base shear. From analysis, it is found that time period for bare frame model

is almost 90 to 135 percent more, when compared to other models. By Prashant D1, Dr. Jagadish Kori G2.

1.1 Background

Nonlinear static (pushover) Analysis has been superior in excess of the history 20 years & has now

develop into the most selected Analysis technique for Design & seismic presentation estimation purposes

because this put into practice is comparatively simple & considers post- elastic performance. On the other

hand, this technique includes confident approximations & simplifications due to which some amount of

variation is always possible to survive i.e., to exists in the seismic demand estimation of pushover analysis.

1.2Concept of pushover analysis

A Pushover (Non Linear) Analysis is presented by been subjected a construction to a monotonically rising

prototype of tangential load, on behalf of Inertial Forces which would exist skilled through construction

when subject towards the ground quaking. Beneath incrementally rising weights a variety of structured

fundamentals can yield in sequence accordingly. At each event, the constructions experience a defeat in

rigidity. By means of Pushover (Non Linear) analysis, a excellence non-linear Force Displacement

connection be able to determined.

Unlike Forces Distributions can be used to symbolize the Earthquake loads strength. If a Pushover

(Non Linear) Analysis is in conditions about Response Demand vs. Capacity. Whether Demand curvature

intersects capacity envelope lock to stretchy range, (Figure a), subsequent to that construction has a high-

quality confrontation. Whether the Demand Curve intersect the Capacity Curve by means of minute

Static Linear and Non Linear (Pushover) Analysis


preserve about strength & deformation capacity, (fig: b)

construction resolve act badly throu

Retrofitted to keep away from the

1.3. PLASTIC HINGES

Plastic hinges are failure points at which the rotation reaches infinity, there by which the struc

fails resulting in structural collapse. In this

direction of location this hinges in earth

PLASTIC HINGE occurrence intended for 3

dislocation Levels. Hinging Patterns be situated

to pattern intended for 3 Building be fairly parallel

Beam Ends & Base Columns about Lower Stories, after that Propagates in the direction of higher Stories &

carry on by means of elasticity about

occurs on proceedings ‘B’, ‘IO’ &

there inadequate.(As per FIG: 3)

Figure 1 Configuration of plastic Hinges in Building at

Figure 2 Hinges Patterns Five Story Building Intended For Dissimilar Dislocation Levels

n Linear (Pushover) Analysis of RC Building On Sloping Grounds On Medium Soils In

Different Zones


preserve about strength & deformation capacity, (fig: b), after that it be able to

construction resolve act badly throughout the compulsory seismic excitation &

prospect main injure otherwise fall down.

Plastic hinges are failure points at which the rotation reaches infinity, there by which the struc

fails resulting in structural collapse. In this Non-linear (pushover) Static Analysis the objective is

direction of location this hinges in earthquake retaining structural members for different incremental loads

occurrence intended for 3 Building mechanism has be

Hinging Patterns be situated in fig 2, 3 & 4. Relationship about

uilding be fairly parallel. PLASTIC HINGES occurrences Starts by means of


about center middle columns inside higher stories.

n proceedings ‘B’, ‘IO’ & ‘LS’ correspondingly, quantity about harm inside 3

Configuration of plastic Hinges in Building at what time it is subjected to Pushover

Mechanisms

Hinges Patterns Five Story Building Intended For Dissimilar Dislocation Levels

Building On Sloping Grounds On Medium Soils In

[email protected]

, after that it be able to done so as to that

he compulsory seismic excitation & need on the way to

Plastic hinges are failure points at which the rotation reaches infinity, there by which the structural member

nalysis the objective is in the

quake retaining structural members for different incremental loads.

uilding mechanism has being obtaining on dissimilar

about fig 2, 3 & 4 reveal so as

GES occurrences Starts by means of


center middle columns inside higher stories. Other than as elasticity

quantity about harm inside 3 Buildings are be

what time it is subjected to Pushover Plastic Hinge

Hinges Patterns Five Story Building Intended For Dissimilar Dislocation Levels



Figure 3 Buildings on sloping grounds with different sloping angles

1.4. BASE ISOLATION

It is too recognized as Seismic Base Isolation, be single about trendiest means of caring the building from

Earthquake forces. It’s be the group about structural fundamentals whose be supposed to considerably de-

couple a super-structure as of Its sub-structure hidden on top of quaking Ground therefore caring a

Building or non-Building structures reliability.

1.5. DESCRIPTION OF STRUCTURES

The structure chosen is of type setback –step back which is 4 to 7-storied with distinct hill slopes varying

from 00 to 40

0 degrees. The occurrence of abrupt lessening of the lateral dimension of the building at exact

levels of the elevation. This building class is known as ‘setback and step back building’. The structure

substance in which is chosen subjected to less torsion effect. (As per TABLE-2) & (As per FIG-4).

Table 1 Types of Seismic Analysis Methods

Type Usual name Dynamic Effects Material Non-linearity

Linear static Similarly Static No No

Static Linear Dynamic Response Spectrum Yes No

Non-Linear Static Pushover Analysis No Yes

Non-Linear Dynamic Time History Yes Yes

2. OBJECTIVES

The purpose about job is on the way to learn linear & nonlinear (PUSHOVER) action and performance

of building frame on sloping ground depending on various hill slopes of medium soil & number of stories.

The objective is as follows:

1. To learn the difference of Base shear, Displacement, Drifts w.r.t variation in various hill slopes of medium

soil.

2. To learn the Target displacement, Performance i.e., Plastic hinge formation in various hilly slopes. And

finding the angle that subjected to less torsion & which is safe in increasing the height of building.

3. An isolated bearing is used to reduce the earthquake effect on the building & finding hinges when it is

subjected to pushover (Non Linear) analysis.

4-BAY 00 4-BAY 16.32

0 4-BAY 21.58

0

4-BAY 26.560

4-BAY 31.560

Static Linear and Non Linear (Pushover) Analysis of RC Building On Sloping Grounds On Medium Soils In

Different Zones


3. METHODOLOGY

3.1. SCOPE ABOUT CURRENT STUDY

In the current study, the frame is modeling & analyzed of the RCC frame beneath the gravity & earthquake

loads & applying pushover (Non Linear) analysis using ETABS software. From this we can study load

deformation curves, the target displacement & hinges formation at different stages.

Analysis & Design together pressure seismic activity presentation about Buildings. Understanding the

seismic performance is achievable not more than all the way through appropriate Analyses about Building

so as to captures every one of behavioral proceedings likely inside the Buildings throughout Earth-quakes.

In addition to calculating seismic performance it is likely simply throughout realistic design so as to ensure

every behavioral event measured inside the building throughout Analysis. Designed for a innovative

building, design must duplicate Analysis performed, & for assessing an obtaining Building, Analysis must

assess design performed.

3.2. Structure Earth quake analysis

• Linear Static method

• Linear dynamic method

o Response Spectrum method

o Time history method

• Nonlinear Static (Pushover analysis) method

• Nonlinear dynamic method

As per IS-1893:2002, Methods Adopted are

• Equivalent Static Lateral Force (or) Seismic Coefficient technique

• Response Spectrum technique

• Time history technique

3.3. ANALYSIS METHODS

Static Analysis Techniques be generally classifies because of Linear Static & non-linear (PUSHOVER)

Static Analysis. In linear static analysis will make the effect of the superior modes of shaking & the real

sharing of forces in the elastic range i.e., Which Response of Buildings are unspecified while linear

stretchy way .This Analysis be passed elsewhere at the same time as per IS: 1893-2002(Part-1) Non-linear

Static (PUSHOVER) Analysis be an development in excess of Linear Static & Linear Dynamic Analysis in

the sense i.e., It allow the in-elastic performance about construction. The non-linear (PUSHOVER)

Analysis about construction be Iterative technique .This is Depends on top of concluding dislocation,

while efficient damp depending on top of hysteric force defeat owing towards in-elastic deformation ‘h’

inside twist depending on the concluding dislocation. This makes the Analysis method Iterative. Trouble

inside result is face close to final loads, while rigidity Matrix on This end becoming harmful specific

owing towards unsteadiness about construction becoming a device. SOFTWARE obtainable towards

performing non-linear (PUSHOVER) Static Analysis as ETABS, (Extended Three Dimensional Building

System) & structural analysis program limited constituent Program so as to Works by means of

multifaceted Geometry & monitor deformations on every hinge towards conclude final de-formation. It has

fitted default intended for ACI-318 substance property and ATC40 & FEMA-273 Hinge property. Too It

have being ability intended for inputting every substance otherwise Hinge Property. E-TABS deal by

means of Buildings simply. The Analysis in E-TABS Involves subsequent 4 steps:

N.V. Mohanakrishna and C


Step. 1. Modeling, 2.Linear static A

Chart explains the Curve force v/s.

1. End (A) correspond in the direction of unload

2. End (B) represent elasticity about

3. Ordinate on (C) correspond in the direction of supposed force and A

direction of de-formation on Which important force

4. Drop as of (C) in the direction of

direction of horizontal weights

5. Remaining conflict as of (D)

Gravity weights. Away from end

Longer be there continued.

4. RESULTS AND DISCUSSI

(As per FIGURES—4, 5, 6,7, &8 and TABLE

4-BAY when we use only fixed supports

Figure



Modeling, 2.Linear static Analysis, 3.Designing, 4.PUSHOVER (Non Line

/s. deformation

in the direction of unloading situation.

about constituent.

Ordinate on (C) correspond in the direction of supposed force and Abscissa on (C) correspond in the

formation on Which important force dreadful conditions begin.

in the direction of (D) represent primary breakdown about constituent and conflict in the

horizontal weights outside end (C) be more often than not undependable.

) in the direction of (E) allow Frame fundamentals in the direction of maintain

way from end (E), greatest Deformation ability, Gravity weight

RESULTS AND DISCUSSIONS

5, 6,7, &8 and TABLE—3) DRIFTS

BAY when we use only fixed supports 4-bay when we are using isolated bearing

igure 4 Results From Linear Static Analysis

[email protected]

4.PUSHOVER (Non Linear) Analysis.

scissa on (C) correspond in the

dreadful conditions begin.

represent primary breakdown about constituent and conflict in the

be more often than not undependable.

rame fundamentals in the direction of maintain

, Gravity weight be able to rejection

bay when we are using isolated bearing

Static Linear and Non Linear (Pushover) Analysis


Figure 5 4

Figure 6: 4

Figure 7 Pushover Curve In X

n Linear (Pushover) Analysis of RC Building On Sloping Grounds On Medium Soils In

Different Zones


4 Bay Displacements When We Use Fixed Supports

4 Bay Displacements When We Use Isolated Bearings

Pushover Curve In X- Direction Figure 8 Hinge Performances

Building On Sloping Grounds On Medium Soils In

[email protected]

Bay Displacements When We Use Fixed Supports

Bay Displacements When We Use Isolated Bearings

Hinge Performances Of Structures



Table 2 Complete information about Buildings

Common particulars about Building

Number about Story 4 to 7

Storey Height Floor to Floor Height=3.5mts

Plinth Height=1.75mts

Frame system of Building OMRF

Model of concrete Floors Rigid

Building use Commercial Building

Foundation type Stepped

Seismic Zone III , IV , V

Type of soil MEDIUM SOIL

Material Properties

Concrete Grade M40

Steel Grade 500 N/mm2

Young’s Modulus E of M40 5000√fck

Concrete Density 25 KN/cub-m

Poison’s ratio of concrete 0.2

Density of Brick masonary 20 KN/m3

Construction members

Slab thickness 0.15mts

All Beam size For 4 storied=0.23*0.45 m

For 5 storied=0.30*0.45 m

All Column size For 4 storied=0.23*0.50 m

For 5 storied=0.30*0.50 m

Wall Thickness full Brick Wall=00.23 m

half Brick Wall=00.115 mt

Unspecified lifeless weight Intensities

Floor Finish (FF) 1.5KN/cub-m

Live load 3KN/cub-m

earthquake (LL) top of slab like per section 7.3.1. & 7.3.2. about IS: 189- (part-1)-2002

Top load 00 kn/Sq-mt

Bottom load 00.25 x 3.0 = 00.75 kN/Sq-m

EARTHQUAKE PARAMETERS

Time period T 0.09h/√d

Impedence factor 1

Sa/g 1/T,2.50

Reduction Factor 3

Load cases for Non-Linear (Pushover) Analysis

(Non

Linear)

Pushover

cases

NAMES LOADS Controlling

through

Forces &

Displacements

1 Gravity DL+0.25LL

2 PUSH X EQ X

3 PUSH Y EQ Y Displacements

Static Linear and Non Linear (Pushover) Analysis of RC Building On Sloping Grounds On Medium Soils In

Different Zones


• The Forces in X-direction is more successful than in Y-direction.

• The Displacement is more in the Medium Soils than in Rock soils.

• In the medium type soils 6th storey is the peak storey for resistance by using isolated bearings.

• The storey drift in any storey should be a minimum partial load factor of 1shall not exceed 0.006 times the

storey height.

• In the 4th storey when the structure was in the normal condition the maximum target displacement(117mm)

and the maximum base shear (533.36kn) has been decreased when the isolated bearings are introduced to

the structure , hence the maximum target displacement (108mm) and maximum base shear (531kn).

• In the 5th storey when the structure was in the normal condition the maximum target displacement (129mm)

and the maximum base shear (681kn) has been decreased when the isolated bearings are introduced to the

structure , hence the maximum target displacement (119mm) and maximum base shear (680.05kn).

5. CONCLUSIONS

1. The performance of RCC frames was investigated by means of the (Non Linear) pushover analysis.

2. From this analysis the observations are as the angle of slope increases base shear increases and displacement

decreases.

3. The base shear acts more in longitudinal direction than in transverse direction.

4. These observations are reduced i.e., displacement, drifts and the large forces it can resist when we are using

isolated bearings at supports at it varies upto nearly 10%.

5. From this we observed that for 16.32, 21.58, 26.56, 31.56 degrees are safe upto 5- bay .But as the bay

increases more no of hinges are to be formed and subjected to collapse region.

REFERENCES

[1] ATC-40: Seismic Evaluation and Retrofit of Concrete Buildings.

[2] FEMA-356: Pre-standard and Commentary for the Seismic Rehabilitation of the Buildings.

[3] Nonlinear static pushover analysis of irregular space frame structure , Govind M1, Kiran K. Shetty2, K.

Anil Hegde3 1M. Tech Final Year (Structures), Department of civil engineering, M.I.T Manipal,

Karnataka, India 2Associate Professor (senior scale), Department of civil engineering, M.I.T Manipal

Karnataka, India 3Senior Structural Consultant, Vimal Anil Structural Consultants, Mangalore,

Karnataka, India

[4] Seismic Analysis of Buildings Resting on Sloping Ground with Varying Number of Bays and Hill

Slopes. Dr. S. A. Halkude1, Mr. M. G. Kalyanshetti2, Mr. V. D. Ingle3 (Civil Engg. Dept. W. I. T.

Solapur, University, India)

[5] Pushover analysis of unsymmetrical framed structures on sloping Ground 1n. Jitendra babu, 2k.V.G.D

balaji & 3s.S.S.V gopalaraju 1Assistant professor, k l university, Guntur, India 2professor, Gitam

university, Visakhapatnam - 530 045, Andhra Pradesh, India 3professor & head Gitam university,

Hyderabad, India

[6] Effect of Irregular Configurations on Seismic Vulnerability of RC Buildings Ravikumar C M1,*, Babu

Narayan K S1, Sujith B V2, Venkat Reddy D1 1Department of Civil Engineering, National Institute of

Technology, Surathkal, 575025, India 2Department of Studies in Civil Engineering, U.B.D.T College of

Engineering, Davangere, 577004, India [email protected], [email protected]

[7] Seismic analysis of buildings resting on sloping Ground by B.GBirajdar1, S.S.Nalawade2.

[8] Effects of plastic hinge properties in nonlinear analysis of reinforced concrete buildings by Mehmet

Intel, Hayri Baytan Ozmen. Dept of Civil Engineering Pamukkale University.

[9] Pankaj Agarwal –Earthquake Resistant Design Of Structure A.K.Chopra-Dynamics of Structures



[10] Numerical Analysis of Seismic Elastomeric Isolation Bearing in the Base-Isolated Building by M.

Jabbareh Asl, M. M. Rahman, A. Karbakhsh from Islamic Azad University, Kerman Branch, Kerman,

Iran

[11] IS1893-2002 Part1; Criteria for Earthquake Resistant Design of structures

[12] IS456-2000; Plain & Reinforced Concrete Code of Practice.