This document presents the development of a deteriorating hysteresis model for cold-formed steel shear wall panels (CFS SWP) based on their physical and mechanical characteristics. The model has been implemented in the Opensees software and validated against experimental results, demonstrating good correlation in shear strength and energy dissipation. Key findings include successful integration of the model as a user-defined material in C++ and its applicability in simulating lateral response under various loading conditions.

1. Deteriorating Hysteresis Model for Cold-Formed Steel Shear Wall Panel Based on Physical and Mechanical Characteristics
OpenSeesDays Portugal 2014 – 4 July 2014
Smail Kechidi*, Nourdine Bourahla
University of Blida 1, Algeria.
*email: kechidi@hotmail.fr
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2. Outline of Presentation Introduction to Cold-Formed Steel Framing system Hysteresis model development Model validation Summary & Conclusions
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OpenSeesDays Portugal 2014 – OPD 2014

3. 3/22
Advantages : Lightness, Recycling, Easy Erection, etc.
Shear Wall Panel (SWP)
Cold Formed Steel framing (CFS) system
OpenSeesDays Portugal 2014 – OPD 2014

4. Other components:
Hold-down
Anchor rods (7/8”)
Shear bolts (3/4”)
Intermediate stud
Steel sheathing
Bottom track
Chord stud
Blocking
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OpenSeesDays Portugal 2014 – OPD 2014
Cold Formed Steel framing (CFS) system
• Steel sheathing/CFS frame shear wall panel

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PGA: 0.25
Max. displacement: 24.0 mm
OpenSeesDays Portugal 2014 – OPD 2014
Cold Formed Steel framing (CFS) system
• CFS shear wall panel behaviour

6. Objectives
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 Development of a smooth hysteresis model for CFS SWP with parameters expressed explicitly in terms of SWP physical and mechanical characteristics
 Hysteresis model implementation into OpenSees using a DLL named CFSSWP
 Model validation through experimental test results
OpenSeesDays Portugal 2014 – OPD 2014

7. Hysteresis model CFSSWP
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CFSSWP deteriorating model can be used to simulate the CFS SWP lateral response when subjected to quasi-static or dynamic loading.
OpenSeesDays Portugal 2014 – OPD 2014

8. Hysteresis model CFSSWP
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Analytical methods for assessing the maximum lateral shear strength capacity of CFS SWP
 Martinez (2007) for Wood sheathed CFS SWP
 Yanari N. and Yu C. (2013) for Steel sheathed CFS SWP
• Backbone curve
OpenSeesDays Portugal 2014 – OPD 2014

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Comparison between monotonic test measurements and numerical model results
OpenSeesDays Portugal 2014 – OPD 2014
B-Spline Algorithm
Hysteresis model CFSSWP
Wood sheathed SWP
Steel sheathed SWP

10. Hysteresis model CFSSWP
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• Hysteresis criteria
OpenSeesDays Portugal 2014 – OPD 2014
Monotone cubic spline Algorithm

11. Hysteresis model CFSSWP
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Comparison between monotonic and cyclic lateral response of CFS SWP
OpenSeesDays Portugal 2014 – OPD 2014
Wood sheathed SWP
Steel sheathed SWP

12. Hysteresis model CFSSWP
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Sc : Screw spacing (mm) ;
H et W : Height and Width of the CFSS SWP (mm), respectively.
OpenSeesDays Portugal 2014 – OPD 2014
• Deterioration criteria

13. Hysteresis model CFSSWP
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• Deterioration criteria
OpenSeesDays Portugal 2014 – OPD 2014

14. C++ script of CFSSWP Hysteresis Model (CFSSWP.h)
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OpenSeesDays Portugal 2014 – OPD 2014

15. C++ script of CFSSWP Hysteresis Model (CFSSWP.cpp)
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OpenSeesDays Portugal 2014 – OPD 2014

16. Hysteresis model validation
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OpenSeesDays Portugal 2014 – OPD 2014
• Modelling of the CFS SWP

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OpenSeesDays Portugal 2014 – OPD 2014
Hysteresis model validation
• Loading protocol

18. Numerical results
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Comparison between test measurements and numerical model results of wood sheathed SWP
Specimen
H/W ratio (mm)
Wood type
Sheathing thickness (mm)
Screw spacing (mm)
Screw number
32
2440/2440
CSP
12.5
102
98
OpenSeesDays Portugal 2014 – OPD 2014

19. Numerical results
19/22
Comparison between test measurements and numerical model results of steel sheathed SWP
Specimen
H/W (mm)
ts (mm)
Fus (MPa)
Fys (MPa)
tf (mm)
Fus (MPa)
Fys (MPa)
Sc (mm)
Vs (N)
3C-a
2440/1220
0.46
391
342
0.87
395
300
150
1560
OpenSeesDays Portugal 2014 – OPD 2014

20. Conclusion
20/22
 Hysteresis model has been developed where its parameters are related to the physical and mechanical characteristics of CFS SWP.
 The model has been integrated into finite element software OpenSees as a user-defined uniaxial material using a DLL written in C++ programming language named CFSSWP.
 The efficiency of the modeling tip and the accuracy of the proposed model have been proved by an acceptable correlation rate between the experimental and the analytical results in terms of shear strength-lateral displacement relationship, as well as the cumulative energy dissipation.
• Conclusions
OpenSeesDays Portugal 2014 – OPD 2014

21. Acknowledgment
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Mr. Omar Bourahla (USTHB University, Algeria) Dr. Iman Shamim (McGill University, Canada) Mr. Ribeiro Filipe (Nova University of Lisbon, Portugal)
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Thank you for your attention
OpenSeesDays Portugal 2014 – OPD 2014
Questions !