restrained braces

1. Buckling Restrained Braces
BY
▸R.SIVA NAGARAJU
▸L .TRINATH

2. Contents
▸Introduction
▸Types of braces
▸Why use BRBF
▸Components
▸Characteristics
▸Connections
▸Tests
▸Survey
▸Advantages
▸Reference structures
▸Conclusion

3. Introduction
• The concept of Buckling
Restrained Braces developed
in Japan by NIPPONS STEEL in
1980’s.
• It is designed to allow
1. Cyclic lateral loads on building
2. Earth quake induced loads

4. • 1. Specially Concentrically Braced
(Frame)
• 2. Buckling Restrained Braced
(Frame)
TYPES OF BRACES

5. Specially
Concentrically
Braced frame

6. Buckling
Restrained
Braced frame

7. Why we use BRBF?
• This structure has high stiffness & high
ductility.
• It yields in both compression and tension
• (no buckling).
• It is a safe guard for building under lateral
loadings coming from earthquake forces.
• This can be moulded by using parameters
like storey drift & base shear.

8. COMPONENTS
• 1. Steel core
• 2. Casing
• 3. Debounding material

9. Buckling-
Restrained
Brace:
Steel Core
+
Casing
AA
Section A-A
Steel Core
Debonding material
Casing
Steel jacket
Mortar
Buckling
Restrained
Brace

10. Characteristics
• It prevents the members from
buckling.
• It illustrates the envelope of
hysteresis curve.
• It acts as a back bone of curve.

11. Connections
• 1. Welded
• 2. Pinned
• 3. Bolted

12. Welded
connections

13. Pinned
connections

14. Bolted
connections

15. Literature survey
S. No Title Author Name Journal Published objective
1. Behavior and design of structures with
buckling-restrained braces
Kim, J., et al. ELSEVIER
Vol:26 (2004)
Maximun displacements, story drifts,
story shears.
2. Design of buckling-restrained braced
frames using nonlinear time history
analysis and optimization
Richard, J. B., et
al.
ASCE
Vol: 135 (2009)
Nonlinear time history analysis and
optimiztion compared to equivalent
lateral forces.
3. Application of buckling-restrained
braces in prefabricated reinforced
concrete frame
Hongnan, w., et
al.
Scientific.net
Vol: 351 (2013)
Retrofit of BRB to the old
prefabricated building.
4. Performance of BRBF and Comparing
it with the OCBF
Talebi, E., et al. International
Journal of Civil
Design of BRBFs compared with
OCBFs under earthquake loads.

16. TESTS
1. Brace test
2. Sub-assemblage test

17. Brace test specimen
Uniaxial Loading

18. Subassemblage test specimen
Axial + Rotational Loading

19. Scale Requirements for
Test Specimens
Brace Test Specimen
0.5 [ Pysc ]prototype  [ Pysc ]specimen  1.5 [ Pysc ]prototype
Subassemblage Test Specimen
[ Pysc ]specimen  [ Pysc ]prototype

20. Advantages
• It is easy to erect.
• Mostly used in seismic retro-fittings.
• It is an alternative for Specially
Concentrically Braced Frame.
• When compared to SCBF, BRBF is
economical.

21. University
of
California
dormitory,
Berkeley
seismic
retrofitting

22. Fujita
Corporation
Headquarter:
Tokyo

23. The new
five-level,
parking
structure
at John
Wayne
Airport
(SNA) in
Tustin

24. Rio Tinto
Stadium,
sandy

25. It minimises the Earth Quake intensity On
the structure.
Using BRBF, will be a great step adopted
by the Civil Enginners during Earthquake.
Conclusion

26. THANKS!
Any questions?