# Section Aggregator
This command is used to construct a SectionAggregator object which aggregates groups previously-defined UniaxialMaterial objects into a single section force-deformation model. Each UniaxialMaterial object represents the section force-deformation response for a particular section degree-of-freedom (dof). There is no interaction between responses in different dof directions. The aggregation can include one previously defined section.
```tcl section Aggregator $secTag $matTag1 $dof1 $matTag2 $dof2 ....... <-section $sectionTag> ```
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unique section tag |
$matTag1 $matTag2 ... |
tag of previously-defined UniaxialMaterial objects |
$dof1 $dof2 ... |
the force-deformation quantity to be modeled by this section object. One of the following section dof may be used: |
P Axial force-deformation |
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Mz Moment-curvature about section local z-axis |
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Vy Shear force-deformation along section local y-axis |
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My Moment-curvature about section local y-axis |
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Vz Shear force-deformation along section local z-axis |
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T Torsion Force-Deformation |
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tag of previously-defined Section object to which the UniaxialMaterial objects are aggregated as additional force-deformation relationships |
EXAMPLE
section Aggregator 2 2 Vy -section 4; # create new section with IDtag 2, taking the existing material tag 2 to represent the shear and adding it to the existing section tag 4, which may be a fiber section where the interaction betweeen axial force and flexure is already considered.
## TheoryRead if you're using moment-curvature in beamWithHinges element to represent moment-rotation, or vice versa
http://earthquakespectra.org/doi/abs/10.1193/1.4000136
Code Developed by: Micheal H. Scott, Oregon State