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ABSTRACT Stability is a very important concept

for steel structures since most steel structures are

governed by stability limit states. Local instability,

such as compression flange buckling, and member

instability, such as buckling of a column, may lead

the structure to collapse. Therefore, stability

provisions of steel design specifications are

continuously improved to capture the real structure

behavior and so to minimize the destabilizing effects.

Direct Analysis Method (DAM) was first introduced

as an alternative to the Effective Length Method

(ELM). Then in 2010 AISC Specification for

Structural Steel Buildings (AISC 360-10) it became

the default stability design method. To perform a

design based on condition of stability, this analysis

method will be used. The method can be applied for

any type of structural members. This method

provides the accurate results for the design of

structural members like beams. The direct analysis

method includes the required strength and available

strength calculations. The direct analysis method

includes the stability consideration for the structures.

This stability in this method is provided for whole

structure and individually to all elements.

In the present study a G+9 story steel frame

structure was analyzed by using direct analysis

method in STAAD Pro V8i Software. The parameters

like deflection, shear, bending, Drift values are

studied at each individual story for checking the

stability of steel frame structure.

Key words: Stability, Effective Length Method,

Direct analysis method, deflection, shear, bending,

Drift.

1. INTRODUCTION

Stability is a very important concept for steel

structures since most steel structures are governed by

stability limit states. Local instability, such as

compression flange buckling, and member instability,

such as buckling of a column, may lead the structure

to collapse. Therefore, stability provisions of steel

design specifications are continuously improved to

capture the real structure behavior and so to minimize

the destabilizing effects.

Direct Analysis Method (DAM) was first acquainted

as an option with the Effective Length Method

(ELM). At that point in 2010 AISC Specification for

Structural Steel Buildings (AISC 360-10) it turned

into the default strength plan strategy

To get reasonable examination results, the solidness

technique utilized in the investigation is significant

alongside the practical demonstrating of the structure.

With the assistance of cutting edge business

programming, itemized 3-D displaying of structures

is conceivable. In any case, there is as yet a

significant admiration in demonstrating that makes

the auxiliary model far from the genuine structure

conduct: associations.

Steel casings are structured under the presumption

that the pillar to-segment association is either

completely unbending or in a perfect world stuck.

Anyway in actuality, any association is neither

completely unbending nor in a perfect world stuck.

Association unbending nature has an impact on the

inside power conveyance of the framework and

horizontal float of the structure. In this manner,

association unbending nature ought to be

demonstrated with the end goal that it mirrors the

association conduct.

ANALYSIS OF STEEL FRAMES USING DIRECT ANALYSIS METHOD BY

USING STAAD Pro V8i Software

Kasa Navin Kumar1, Gowlla Jyothsna

2

1M.Tech Scholar Department of Civil Engineering Malla Reddy Engineering College, Maisammaguda,

Dulapally,Telangana, India,500100.

2 Assistant Professor Department of Civil Engineering Malla Reddy Engineering College, Maisammaguda,

Dulapally,Telangana, India,500100.

JASC: Journal of Applied Science and Computations

Volume VI, Issue VI, JUNE/2019

ISSN NO: 1076-5131

Page No:1897

Objectives of the study

The following are the main objectives of the project

1. To investigation the seismic conduct of G+9 steel

frame building working by utilizing IS 1893:2002

2. The parameters like deflection, shear, bending,

Drift values are studied at each individual story for

checking the stability of steel frame structure.

3. In the present study a G+9 story steel frame

structure was analyzed by using direct analysis

method in STAAD Pro V8i Software.

4. To examination the structures in STAAD Pro V8i

Software.

2. LITERATURE REVIEW

Ziemian et al [1] investigated eleven two-and-three-

dimensional structural systems to evaluate and

compare ELM and DAM. Also advanced-second

order inelastic analyses were used to assess the

adequacy of all design methods. They concluded that

ELM and DAM provide similar results and for beam-

columns subjected to minor-axis bending DAM is

slightly un conservative.

In the study of Surovek et al [2], an 11-bay single-

story frame was studied to discuss the three design

approaches (Direct Analysis Method, Effective

Length Method and Advanced Analysis) for the

assessment of frame stability. The primary attribute

of this frame was that it is sensitive to initial

imperfection effects.

In his study, Prajzner [3] dealt with the evaluation of

case studies including a portal frame, a leaning

column frame, a multi-story structure, and a multi-

bay frame in order to assess the adequacy of ELM

and DAM.

Surovek et al [4] presented an approach that allows

for the consideration of nonlinear connection using

commonly available elastic analysis software. The

partially restrained frames were analyzed using

Direct Analysis Method. The aim of the proposed

connection approach was to simplify the

consideration non-linear connection response in the

analysis of partially restrained frames.

Kartal et al [5] developed a finite element program

SEMIFEM in FORTRAN language to perform

structural analysis that considers semi-rigid

connections. The aim of their study was to investigate

the effect of semi-rigid connections on the structure

behavior.

The formula suggested by Monforton and Wu [6]

was also adopted by Xu [7] in his study on

calculation of critical buckling loads of semi-rigid

steel frames and by Patodi et al [8] in their study on

first order analysis of plane frames with semi-rigid

connections.

3. METHODOLOGY

Methodology

Direct Analysis Method (DAM) was first introduced

in 2005 version of the AISCB Specification for

Structural Steel Buildings as an alternative method to

the Effective Length Method (ELM) and First-Order

Analysis Method. Then in 2010 version of the

specification, it became the standard stability design

method. DAM has many advantages, such as; it

obtains the analysis results more accurately and

realistic, it is applicable to all type of structures and it

eliminates the calculation of K factor.

ELM neglects initial imperfections and inelasticity

during analysis and underestimates member demand.

To compensate this underestimate, it requires the use

of K factor to decrease the member capacity.

Therefore, in ELM, the forces and capacities obtained

do not reflect the real behavior of the structure. In

DAM, initial imperfections and inelasticity are

considered during the analysis and this eliminates the

need for the K factor. Thus, DAM results in a design

which is very close to the real structure behavior.

DAM is the most applicable method among all

stability methods. It can be used for all types of steel

structures such as braced frames, moment frames and

combined systems without any limitation.

4. MODELING AND ANALYSIS OF

BUILDING

Problem statement

Loads acting on the structure are:

1. Dead Load (DL) and Live load (LL) : As per IS

875 (Part 1) (1987) and IS 875 (Part 2) (1987)



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2. Seismic load (SL) : As per IS 1893 (Part 1)

(2002) Approach

3. DL : Self weight of the structure, Floor load and

Wall loads

4. LL : Live load 3.5 KN/sq.m is considered for

floor weight

5. SL : Zone: V (Z=0.36)

6. Rock/ soil type : Medium Rock and Soil site

factor : 1

7. Response reduction factor : 5

8. Importance factor : 1

9. Damping : 0.05%

The preliminary data as is taken up for this study

Analysis of the building

Assigning materials for building

As after creating the beams and columns we

will assign material to them as we require.

Our design is steel design hence we have

assigned the concrete material to the beams

and columns.

Assigning steel Material to Building

Specifying Supports: The supports are first

created (as we created fixed supports) and

then these are assigned to all the lowermost

nodes of structure where we are going to

design the foundation.

The model with the fixed supports

Assigning dead load

The load coming on framed structure due to

self weight of beams, columns, slabs or

walls. This load will act as uniformly

distributed load over the supporting beams.

Live Load: The live load comes on

structure due to extra necessary things in the

house. There will be different Live Loads

acting in the structure due to different uses



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of building. As here we have used various

types of different live loads in our structure.

Assigning area load to the building

SEISMIC LOAD

In X-Direction

Assigning seismic load in X-Direction in

Staad pro

In Z-Direction

Assigning seismic load in Z-Direction in

Staad Pro

Building model in STAAD Pro Software

G+9 Building in staad Pro

Building Displacement

Building shear diagram



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Building bending diagram

5. RESULTS AND ANALYSIS

Building Deflection

Global Deflection

From the above graph it was observed that the value

of global deflection decreases from story 10 to story

1. Generally due to the effect of fixed support at

bottom story the value of deflection increases from

story 1 to story 10

Local Deflection


of local deflection increases from story 10 story 8

after story 8 the deflection decreases story 2 and

gradually increases to story 1. The variation of

deflection occurs due to the effect of irregularity of

building and loading condition.

Story Shear in X Direction


of story shear in X direction increases from story 10

to story 8 after story 8 the value decreases gradually

to bottom story. Due to the effect of seismic load

action in X direction the value of shear increases

initially and decreases finally.

Story shear in Z Direction

Due to the effect of uniform seismic load the value of

shear in Z direction decreases from story 10 to story

1.



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Story Bending in X Direction


of story bending in X direction increases from story

10 to story 8 after story 8 the value decreases

gradually to bottom story. Due to the effect of

seismic load action in X direction the value of shear

increases initially and decreases finally.

Bending in Z Direction

Due to the effect of uniform seismic load the value of

bending in Z direction decreases from story 10 to

story 1

Story Drift

The value of story drift increases from story 10 to

story 1 due to the effect of axial load the value of

drift increases from story 10 to story 1.

Story Stress in N/mm2

Story stress values decreases from story 10 to story 1

due to the effect of loading condition on building.

CONCLUSIONS

From this study the following conclusions were made

1. DAM is the most applicable method among all

stability methods. It can be used for all types of

steel structures such as braced frames, moment

frames and combined systems without any

limitation.

2. The value of global deflection decreases from

story 10 to story 1. Minimum value was

observed as 1.232mm and maximum value is

5.079mm.

3. The optimal value of local deflection was

observed at story 8 with the value of 0.09mm

and the minimum value was observed at story 2

with 0.044mm deflection

4. The value of story shear and bending in X

direction increases from story 10 to story 8 after

that the value decreases with decrease in the

story number. In case of story shear and bending

in Z direction decreases from story 10 to story 1.

5. From story 10 to story 1 the value of story drift

increases.

6. Stress value decreases from story 10 to story 1.

REFERENCES

1) Ziemian,R.D.,Martinez-Garcia,J.M.,“Frame

StudiestoCompareStabilityProvisionsAppearing

inthe2005AISCSpecification”,StabilityandDuctil

ityofSteelStructures,Lisbon, 2006.

2) Surovek,A.E.,Ziemian,R.D.,“TheDirectAnalysis

Method:BridgingtheGapfromLinearElasticAnaly

sistoAdvancedAnalysisinSteelFrameDesign”,Str

ucturesCongress,NewYork,April 2005.



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3) Prajzner,J.,“EvaluationoftheEffectiveLengthMet

hodandtheDirectAnalysisMethodfortheDesign

ofSteelColumnsinFrameStructures”,Universityof

Maryland, Maryland, 2006.

4) Surovek,A.E.,White,D.W.,Leon,R.T.,“Direct

AnalysisforDesignEvaluationofPartially

Restrained Steel Framing Systems”, Journal of

Structural Engineering, September 2005.

5) Kartal, M.E., Başağa, H.B., Bayraktar, A., Muvafık, M., “Effects of Semi-Rigid Connection

on Structural Response”, Electronic Journal of

Structural Engineering (10), 2010.

6) Monforton, G.R., Wu, T.S., “Matrix Analysis of

Semi-Rigidly Connected Frames”, Journal of

Structural Division, ASCE, 89, ST6, 13-42,

1963.

7) Xu, L., “Critical Buckling Loads of Semi-Rigid

Steel Frames”, University of Waterloo.



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