DOI : 10.17577/IJERTV5IS040365
- Open Access
- Total Downloads : 288
- Authors : M. Mohana Ram
- Paper ID : IJERTV5IS040365
- Volume & Issue : Volume 05, Issue 04 (April 2016)
- DOI : http://dx.doi.org/10.17577/IJERTV5IS040365
- Published (First Online): 07-04-2016
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Comparisons of the Different Bracing System with Lateral and Transverse Loading on 2D Steel Frame
M. Mohana Ram
PG Student, Department of Civil Engineering,
Sri Vidya College of Engineering & Technology, Virudhunagar.
Abstract This paper is for identifying the effective bracing system for different kind of loading system like lateral loading and transverse loading of the 2D steel frame. In this paper basic types of bracing are analysed with an example models and compared.
Keywords Bracing, Chevron, X-Cross, Inverted Chevron, Diagonal, 2D Frame, Lateral and Transverse loading
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INTRODUCTION
Most of the times engineers are miss match the bracing type for the steel structure. This is caused due to the miss understand the behaviour of the bracing system and its type, which is used in the steel structure, some bracing are done to resist the lateral loads and some are done to resist the transverse load. Identifying the real need of bracing and providing the required bracing type for a steel structure will make the structure as efficient one. This comparative study will help engineers to choose the correct type of bracing type which will required for different loading type, like lateral and transverse.
In these type of bracing the most commonly used bracing type are first four only, so in this paper first four types are used for the comparison.
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BRACING
Bracing the frame in a steel structure is very important; it will resist the heavy lateral load like wind and earthquake forces. Primarily bracing is done to resist the lateral loads but also sometimes when there is heavy transverse load in steel beam; bracing is also done to resist the transverse load so that bays length can be increased, other words column to column distance can be increased. The foremost purpose of bracing in the steel structure is to increase the ductility of the steel structure, so that the structure can stretch without breaking suddenly.
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TYPES OF BRACING
There are many types of bracing are done for steel structures, but the mostly used types of bracings are mentioned as follows:
-
Single Diagonal Bracing
-
X Cross Bracing
-
Chevron Bracing
-
Inverted Chevron Or V Bracing
-
A Chevron Bracing
-
Braced Chevron Bracing
-
Braced Single Bracing
-
Knee Bracing
-
K Bracing
Fig.1. Types of Basic Bracing
-
-
DESIGN DATA
These are the data taken account for the analysis of the 2D frame.
-
Frame Details:
-
Frame Span 3 M
-
Frame Height 3 M
-
Support Condition Pinned
-
-
Material Property:
-
Members Used ISJB 150 (For Column, Beam, Bracing)
-
Material Used Steel
-
Minimum Yield Stress 250000 Kn/M2
-
Minimum Tensile Stress 410000 Kn/M2
-
Effective Yield Stress 275000 Kn/M2
-
Effective Tensile Stress 451000 Kn/M2
-
Modulus of Elasticity, E -2.100E+08 Kn/M2
-
Poisson Ratio 0.3
-
Co-efficient of Thermal Expansion, A 1.170E-05 1/C
-
-
LOAD DETAILS:
Frames are loaded transversely and laterally as separately, with Dead load of 2KN/M of Uniformly Distributed load (UDL). Self- Weight is not considered for analysis, only dead load is considered.
All bracing are symmetrical in model, expect the single diagonal bracing. So Lateral loading is done, in single diagonal bracing, on both sides separately, so that effect way of bracing can be identified in single diagonal bracing.
-
COMPARISION
Comparisons have been done for various outputs for both Lateral and Transverse Loading of the frame. Compared output are Support reaction on X and Z axis of the frame, Joint Displacement on X and Z axis, Joint rotation, Support rotation, Shear force and Bending Moment of the frame which is loaded.
Support Rotation For Transverse Loading
8.00E-04
6.00E-04
4.00E-04
2.00E-04
0.00E+00
-2.00E-04
-4.00E-04
-6.00E-04
-8.00E-04
Support Rotation For Transverse Loading
8.00E-04
6.00E-04
4.00E-04
2.00E-04
0.00E+00
-2.00E-04
-4.00E-04
-6.00E-04
-8.00E-04
Conven tional
Conven tional
Support 1 -5.80E-05 -3.90E-05 -0.000383 -0.000109 -0.000654
Support 2 5.80E-05 3.90E-05 0.000293 0.000455 0.000654
Support 3 0.000383
Support 1 -5.80E-05 -3.90E-05 -0.000383 -0.000109 -0.000654
Support 2 5.80E-05 3.90E-05 0.000293 0.000455 0.000654
Support 3 0.000383
X – Chevro "V"
Cross n Bracin g
X – Chevro "V"
Cross n Bracin g
Single Diagon al
Single Diagon al
Support Rotation In Radian
Support Rotation In Radian
Table 2 Support Rotation Comparison for Transverse Loading
Support Reaction For Transverse Loading
3.5
3
Support Reaction Force in Kn
Support Reaction Force in Kn
2.5
2
Rotation in Radian
Rotation in Radian
1.5
Joint 1 0.000762 0.000164 0.000779 0.001103 0.001336
Joint 2 -0.000762 2.64E-19 -0.000779 -0.000876 -0.001336
Joint 3 -0.000164
Joint 1 0.000762 0.000164 0.000779 0.001103 0.001336
Joint 2 -0.000762 2.64E-19 -0.000779 -0.000876 -0.001336
Joint 3 -0.000164
X-Cross
X-Cross
Chevro "V"
Chevro "V"
n Bracing
n Bracing
Single Conven Diagon
al tional
Single Conven Diagon
al tional
Table 1 Joint Rotation Comparison for Transverse Loading
1
0.5
0
-0.5
-1
-1.5
Support 1 X-Axis
Support 1 Z-Axis
Support 2 X-Axis
Support 2 Z-Axis
Support 3 X-Axis
Support 3 Z-Axis
X-Cross Chevron
"V"
l
0.893
0.901
0.175
0.2
0.299
3
3
1.694
3
3
-0.893
-0.901
-5.00E-16
-0.2
-0.299
3
3
2.613
3
3
-0.175
1.694
l
0.893
0.901
0.175
0.2
0.299
3
3
1.694
3
3
-0.893
-0.901
-5.00E-16
-0.2
-0.299
3
3
2.613
3
3
-0.175
1.694
Bracing
Joint Rotation For Transverse Loading
0.0015
0.001
0.0005
0
-0.0005
-0.001
-0.0015
Joint Rotation For Transverse Loading
0.0015
0.001
0.0005
0
-0.0005
-0.001
-0.0015
Single Diagona
Convent ional
Table 3 Support Reaction Comparison for Transverse Loading
Shear Force For Transverse Loading
Joint Displacement For Transverse Loading
8.00E-05
6.00E-05
4.00E-05
2.00E-05
0.00E+00
-2.00E-05
-4.00E-05
-6.00E-05
5
0
5
0
0
0
1
1
-5
-5
2
Distance In Meter
2
Distance In Meter
3
3
4
4
X-Cross "V" Bracing
Conventional
X-Cross "V" Bracing
Conventional
Chevron
Single Diagonal
Chevron
Single Diagonal
Displacement In Meter
Displacement In Meter
Axis Title
Axis Title
Shear Force For Transverse Loading
Joint Displacement For Transverse Loading
8.00E-05
6.00E-05
4.00E-05
2.00E-05
0.00E+00
-2.00E-05
-4.00E-05
-6.00E-05
X-Cross Chevron "V"
Bracing
X-Cross Chevron "V"
Bracing
Single Diagona l
Single Diagona l
Convent ional
Convent ional
Table 6 Shear Force Comparison for Transverse Loading On Beam
X-Axis
X-Axis
Joint 1
Joint 1
Joint 2
Joint 2
Member
Joint 1 -2.16E-06 4.37E-07 -1.32E-06 5.70E-05 2.37E-06
Joint 1 -2.16E-06 4.37E-07 -1.32E-06 5.70E-05 2.37E-06
Z-Axis -3.40E-05 -2.00E-05 -2.70E-05 -4.60E-05 -4.80E-05
Z-Axis -3.40E-05 -2.00E-05 -2.70E-05 -4.60E-05 -4.80E-05
X-Axis 2.16E-06
0 1.32E-06 5.00E-05 -2.37E-06
X-Axis 2.16E-06
0 1.32E-06 5.00E-05 -2.37E-06
Joint 2 -3.40E-05 -3.80E-05 -2.70E-05 -4.80E-05 -4.80E-05
Joint 2 -3.40E-05 -3.80E-05 -2.70E-05 -4.80E-05 -4.80E-05
Z-Axis
Joint 3
Z-Axis
Joint 3
X-Axis
Joint 3 Z-Axis
X-Axis
Joint 3 Z-Axis
-4.37E-07
-4.37E-07
-2.00E-05
-2.00E-05
Table 4 Joint Displacement Comparison for Transverse Loading
Bending Moment For Transverse Loading
5
4
3
Bending Moment In Kn.M
Bending Moment In Kn.M
2
1
0
-1
-2
-3
-4
0
0.5
1
1.5
2
2.5
3
Conventional
-0.9
0.352
1.102
1.352
1.102
0.352
-0.9
Single Diagonal
-0.9
0.296
0.996
1.196
0.897
0.097
-1.2
"V" Bracing
-1.15
0.102
0.852
1.102
0.852
0.102
-1.15
Chevron
-0.13
0.257
0.142
-0.47
0.142
0.257
-0.13
X-Cross
-1.16
0.094
0.844
1.094
0.844
0.094
-1.16
0
0.5
1
1.5
2
2.5
3
Conventional
-0.9
0.352
1.102
1.352
1.102
0.352
-0.9
Single Diagonal
-0.9
0.296
0.996
1.196
0.897
0.097
-1.2
"V" Bracing
-1.15
0.102
0.852
1.102
0.852
0.102
-1.15
Chevron
-0.13
0.257
0.142
-0.47
0.142
0.257
-0.13
X-Cross
-1.16
0.094
0.844
1.094
0.844
0.094
-1.16
-5 Distance In Meter
X-Cross Chevron
"V" Bracing Single Diagonal Conventional
Table 5 Bending Moment Comparison for Transverse Loading On Loaded Beam Member
Joint Rotation For Lateral Loading
Joint 1
Joint 2
Joint 3
X-Cross
-0.00084
-2.30E-05
Chevron
-0.00078
3.80E-05
1.30E-05
"V" Bracing
-0.00096
0.000203
Single Diagonal Towards Load
-0.00114
7.10E-05
Single Diagonal Against Load
-0.00106
2.66E-04
Conventional
0.000141
0.00024
Joint 1
Joint 2
Joint 3
X-Cross
-0.00084
-2.30E-05
Chevron
-0.00078
3.80E-05
1.30E-05
"V" Bracing
-0.00096
0.000203
Single Diagonal Towards Load
-0.00114
7.10E-05
Single Diagonal Against Load
-0.00106
2.66E-04
Conventional
0.000141
0.00024
0.0004
0.0002
Rotation In Radian
Rotation In Radian
0
-0.0002
-0.0004
-0.0006
-0.0008
-0.001
-0.0012
-0.0014
Table 7 – Joint Rotation Comparison for Lateral Loading
Support Rotation For Lateral Loading
Rotation In Radian
Rotation In Radian
Joint 1
Joint 2
Joint 3
X-Cros
0.00128
0.00022
Chevron
0.00115
5.80E-05
"V" Bracing
0.00229
0.00029
1.70E-05
Single Diagonal Towards Load
0.00139
6.10E-05
Single Diagonal Against Load
0.00234
0.00023
Conventional
0.00091
0.000774
Joint 1
Joint 2
Joint 3
X-Cross
0.00128
0.00022
Chevron
0.00115
5.80E-05
"V" Bracing
0.00229
0.00029
1.70E-05
Single Diagonal Towards Load
0.00139
6.10E-05
Single Diagonal Against Load
0.00234
0.00023
Conventional
0.00091
0.000774
0.0025
0.002
0.0015
0.001
0.0005
0
Table 8 Support Rotation Comparison for Lateral Loading
Support Reaction Force In Kn
Support Reaction Force In Kn
X-
Cross
Chevro n
"V"
Bracin g
Single Diagon al Towar ds Load
Single Diagon al Agains t Load
Conve ntional
Support 1 X-Axis
-4.106
-4.519
-2.488
-6.002
-2.507
-4.353
Support 1 Z-Axis
-3
-3
-3.098
-3
-3
-3
Support 2 X-Axis
-1.894
-1.481
-3.54
0.0015
-3.493
-1.647
Support 2 Z-Axis
3
3
0.197
3
3
3
Support 3 Z-Axis
0.028
Support 3 Z-Axis2
2.902
X-
Cross
Chevro n
"V"
Bracin g
Single Diagon al Towar ds Load
Single Diagon al Agains t Load
Conve ntional
Support 1 X-Axis
-4.106
-4.519
-2.488
-6.002
-2.507
-4.353
Support 1 Z-Axis
-3
-3
-3.098
-3
-3
-3
Support 2 X-Axis
-1.894
-1.481
-3.54
0.0015
-3.493
-1.647
Support 2 Z-Axis
3
3
0.197
3
3
3
Support 3 Z-Axis
0.028
Support 3 Z-Axis2
2.902
Support Reaction For Lateral Loading 4
3
2
1
0
-1
-2
-3
-4
-5
-6
-7
8
Bending Moment In Kn.M
Bending Moment In Kn.M
6
4
2
0
-2
-4
-6
-8
-10
Bending Moment For Lateral Loading
-12
0
1.5
3
Conventional
0
-4.2801
-4.0603
Single Diagonal 1.11E-16
-1.5109
1.4782
Single Diaglonal Towards Load
0.8655
-1.3207
0.993
"V" Bracing
-1.11E-16
-1.4822
1.5355
Chevron
0.8905
-1.1876
1.2343
X-Cross
0.7821
-1.2282
1.2609
-12
0
1.5
3
Conventional
0
-4.2801
-4.0603
Single Diagonal 1.11E-16
-1.5109
1.4782
Single Diaglonal Towards Load
0.8655
-1.3207
0.993
"V" Bracing
-1.11E-16
-1.4822
1.5355
Chevron
0.8905
-1.1876
1.2343
X-Cross
0.7821
-1.2282
1.2609
Against Load
X-Cross Chevron "V" Bracing
Joint Displacement In Meter
Joint Displacement In Meter
Table 9 Support Reaction Comparison for Lateral Loading
Joint Displacement For Lateral Loading
0.002
0.0015
0.001
0.0005
0
-0.0005
-0.001
-0.0015
-0.002
Joint Displacement For Lateral Loading
0.002
0.0015
0.001
0.0005
0
-0.0005
-0.001
-0.0015
-0.002
Conve ntiona l
Conve ntiona l
X-Axis 0.0001 0.00018 0.00026 0.00024 0.00021 0.0018
X-Axis 0.0001 0.00018 0.00026 0.00024 0.00021 0.0018
Joint 1 2.10E-0 -1.80E- 4.60E-0 -7.62E- 4.80E-0 1.00E-0
Joint 1 2.10E-0 -1.80E- 4.60E-0 -7.62E- 4.80E-0 1.00E-0
Joint 2 8.50E-0 0.00015 0.00023 0.00019 0.00021 -0.0018
Joint 2 8.50E-0 0.00015 0.00023 0.00019 0.00021 -0.0018
Joint 2 -2.00E- 1.10E-0 -4.60E- -4.80E- 5.73E-0 -1.00E-
Joint 2 -2.00E- 1.10E-0 -4.60E- -4.80E- 5.73E-0 -1.00E-
Type -11 Bending Moment Comparison fr Lateral Loading On Loaded Column Member
Shear Force For Lateral Loading
0
1.5
3
Conventional
4.353
1.353
-1.647
Single Diagonal Against Load
2.507
-0.493
-3.493
Single Diagonal Towards Load
2.958
-0.042
-3.042
"V" Bracing
2.488
-0.512
-3.512
Chevron
2.885
-0.115
-3.115
X-Cross
2.841
-0.159
-3.159
0
1.5
3
Conventional
4.353
1.353
-1.647
Single Diagonal Against Load
2.507
-0.493
-3.493
Single Diagonal Towards Load
2.958
-0.042
-3.042
"V" Bracing
2.488
-0.512
-3.512
Chevron
2.885
-0.115
-3.115
X-Cross
2.841
-0.159
-3.159
20
15
Axis Title
Axis Title
10
5
0
-5
-10
-15
-20
X-Cross Chevron
"V" Bracing Single Diagonal Towards Load
Single
Diago X- Chevr "V" nal Cross on Braci Towar
ng ds
Load
Single
Diago X- Chevr "V" nal Cross on Braci Towar
ng ds
Load
Single Diago nal Again st Load
Single Diago nal Again st Load
Joint 1
Joint 1
Z-Axis
Z-Axis
X-Axis
X-Axis
Z-Axis
Joint 3
Z-Axis
Joint 3
X-Axis
Joint 3 Z-Axis
X-Axis
Joint 3 Z-Axis
0.00015
0.00015
Single Diagonal Against Load
Conventional
-9.02E-
-9.02E-
Table 10 Joint Displacement Comparison for Lateral Loading
Type 12 – Shear Force Comparison For lateral Loading On Loaded Column member
-
RESULT
Its very clear from the comparison, which for Transverse Loading Chevron Bracing is effective and for Lateral Loading X Cross Bracing is effective.
-
CONCLUSION
Now this comparative study will help engineers to choose the correct type of bracing type which will required for different loading type like lateral and transverse.
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-
Roger L. Brokenbrough, Frederick S. Mersith, Structural Steel Designers Handbook, Third Edition, ISNB-0-07-008782-2.
-
Dr.P.Dayaratnam, Design of Steel Structure, S.Chand & Company Pvt. Ltd, Second Edition.
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S.D.Rajan, Introduction to Structural Analysis & Design, Wiley India Pvt. Ltd, ISBN-10:8126541369
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Dr.R.Vaidyanathan, Structural Analysis Vol I, Lakshmi Publication, Third Edition (2007), ISBN-10:8131807819
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S.S.Bhavikatti, Structural Analysis Vol I, S.Chand & Company Ltd, Fourth Edition (Oct 2010), ISBN-10:8125942696.