CastFuse

This command is used to construct a CastFuse uniaxial material. The CastFuse material simulates the hysteretic response a cast yielding fuse (CSF) for concentrically braced frames. The details of a CSF-brace are discussed in Gray et al. [1,2]. Isotropic hardening is modeled with the rules developed by Filippou et al. [3].

uniaxialMaterial Cast $matTag $n $bo $h $fy $E $L $b $Ro
        $cR1 $cR2 <$a1 $a2 $a3 $a4>

matTag

integer tag identifying material

n

Number of yield fingers of the CSF-brace

bo

Width of an individual yielding finger at its base of the CSF-brace

h

Thickness of an individual yielding finger

fy

Yield strength of the steel material of the yielding finger

E

Modulus of elasticity of the steel material of the yielding finger

L

Height of an individual yielding finger

b

Strain hardening ratio

Ro

Parameter that controls the Bauschinger effect. Recommended Values for $Ro=between 10 to 30

cR1

Parameter that controls the Bauschinger effect. Recommended Value $cR1=0.925

cR2

Parameter that controls the Bauschinger effect. Recommended Value $cR2=0.150

a1

isotropic hardening parameter, increase of compression yield envelope as proportion of yield strength after a plastic deformation of $a2*(P<sub>p</sub>/K<sub>p</sub>)

a2

isotropic hardening parameter (see explanation under $a1). (optional default = 1.0)

a3

isotropic hardening parameter, increase of tension yield envelope as proportion of yield strength after a plastic deformation of $a4*(P<sub>p</sub>/K<sub>p</sub>)

a4

isotropic hardening parameter (see explanation under $a3). (optional default = 1.0)


Gray et al. [1] showed that the monotonic backbone curve of a CSF-brace with known properties (n, b<sub>o</sub>, h, L, fy, E) after yielding can be expressed as a close-form solution that is given by,

P = P<sub>p</sub>/cos(2d/L), in which d is the axial deformation of the brace at increment i and P<sub>p</sub> is the yield strength of the CSF-brace and is given by the following expression

P<sub>p</sub> = nb<sub>o</sub>h<sup>2</sup>f<sub>y</sub>/4L

The elastic stiffness of the CSF-brace is given by,

K<sub>p</sub> = nb<sub>o</sub>Eh<sup>3</sup>f<sub>y</sub>/6L<sup>3</sup>


Examples:


References:

[1]

Gray, M.G., Christopoulos, C., Packer, J.A., (2010). “Cast Steel Yielding Fuse for Concentrically Braced Frames,” Proceedings of the 9th U.S. National and 10th Canadian Conference on Earthquake Engineering, July 25-29, 2010, Toronto, Ontario, Canada, paper No. 595.

[2]

Gray, M.G., Christopoulos, C., Packer, J.A., Lignos, D.G. (2012). “Development, Validation and Modeling of the New Cast Steel Yielding Brace System,” Proceedings ASCE Structures Congress, March 29th-31st, Chicago, IL, USA, SEI institute.

[3]

Filippou, F. C., Popov, E. P., Bertero, V. V. (1983). “Effects of Bond Deterioration on Hysteretic Behavior of Reinforced Concrete Joints,” Report EERC 83-19, Earthquake Engineering Research Center, University of California, Berkeley.

Code Developed by : by Dr. Dimitrios G. Lignos, (McGill University)

Back to top