View source for Force-Based Beam-Column Element

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This command is used to construct a force beam element object, which is based on the non-iterative (or iterative) force formulation, and considers the spread of plasticity along the element.

{| 
| style="background:yellow; color:black; width:800px" | '''element forceBeamColumn $eleTag $iNode $jNode $numIntgrPts $secTag $transfTag <-mass $massDens> <-iter $maxIters $tol> <-integration $intType>'''
|}

To change the sections along the element length, the following form of command may be used:

{| 
| style="background:yellow; color:black; width:800px" | '''element forceBeamColumn $eleTag $iNode $jNode $numIntgrPts -sections $secTag1 $secTag2 ... $transfTag <-mass $massDens> <-iter $maxIters $tol> <-integration $intType>'''
|}


Alternative command (kept for backward compatability) is:

{| 
| style="background:yellow; color:black; width:800px" | '''element nonlinearBeamColumn $eleTag $iNode $jNode $numIntgrPts $secTag $transfTag <-mass $massDens> <-iter $maxIters $tol> <-integration $intType>'''
|}


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{|
|  style="width:150px" | '''$eleTag''' || unique element object tag
|-
|'''$iNode $jNode''' || end nodes
|-
| '''$numIntgrPts''' || number of integration points along the element.
|-
| '''$secTag''' || identifier for previously-defined section object
|-
| '''$secTag1 $secTag2 ...''' || $numIntgrPts identifiers of previously-defined section object
|-
| '''$transfTag''' || identifier for previously-defined coordinate-transformation (CrdTransf) object
|-
| '''$massDens''' || element mass density (per unit length), from which a lumped-mass matrix is formed (optional, default=0.0)
|-
| '''$maxIters''' || maximum number of iterations to undertake to satisfy element compatibility (optional, default=1)
|-
| '''$tol''' ||tolerance for satisfaction of element compatibility (optional, default=10-16)
|-
| '''$intType''' || numerical integration type, options are Lobotto, Legendre, Radau, NewtonCotes, Trapezoidal (optional, default= Lobotto)
|}


NOTE:

#The default integration along the element is based on Gauss-Lobatto quadrature rule (two integration points at the element ends).
#The default element is prismatic, i.e. the beam is represented by the section model identified by $secTag at each integration point.
#The -iter switch enables the iterative form of the flexibility formulation. Note that the iterative form can improve the rate of global convergence at the expense of more local element computation.
#The valid response elements that an element of this type will respond to are:
## force or globalForce
## localForce
## basicForce
## section $sectionTag $arg1 $arg2 ...
## basicDeformation
## plasticDeformation
## inflectionPoint
## tangentDrift
## integrationPoints
## integrationWeights
#Here is a link to the source code to obtain information about the location and weight of the Gauss-Lobatto integration points [http://opensees.berkeley.edu/WebSVN/filedetails.php?repname=OpenSees&path=%2Ftrunk%2FSRC%2Felement%2FforceBeamColumn%2FLobattoBeamIntegration.cpp]


EXAMPLE:

element forceBeamColumn 1 2 4 5 8 9; # force beam column element added with tag 1 between nodes 2 and 4 that has 5 integration points, each using section 8, and the element uses geometric transformation 9


FURTHER DOCUMENTATION ON INTEGRATION OPTIONS:

[[image:IntegrationTypes.pdf]]

REFERENCES:

*Neuenhofer, Ansgar, FC Filippou. Geometrically Nonlinear Flexibility-Based Frame Finite Element. ASCE Journal of Structural Engineering, Vol. 124, No. 6, June, 1998. ISSN 0733-9445/98/0006-0704-0711. Paper 16537. pp. 704-711.

*Neuenhofer, Ansgar, FC Filippou. Evaluation of Nonlinear Frame Finite-Element Models. ASCE Journal of Structural Engineering, Vol. 123, No. 7, July, 1997. ISSN 0733-9445/97/0007-0958-0966. Paper No. 14157. pp. 958-966.

*Neuenhofer, Ansgar, FC Filippou. ERRATA -- Geometrically Nonlinear Flexibility-Based Frame Finite Element. ASCE Journal of Structural Engineering, Vol. 124, No. 6, June, 1998. ISSN 0733-9445/98/0006-0704-0711. Paper 16537. pp. 704-711.

*Taucer, Fabio F, E Spacone, FC Filippou. A Fiber Beam-Column Element for Seismic Response Analysis of Reinforced Concrete Structures. Report No. UCB/EERC-91/17. Earthquake Engineering Research Center, College of Engineering, University of California, Berkeley. December 1991.

*Spacone, Enrico, V Ciampi, FC Filippou. A Beam Element for Seismic Damage Analysis. Report No. UCB/EERC-92/07. Earthquake Engineering Research Center, College of Engineering, University of California, Berkeley. August 1992.


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Code Developed by: <span style="color:blue"> Micheal H. Scott, Oregon State University </span>