Discovering OpenSees -- Force-based Element vs. Displacement-based Element

• Discovering_OpenSees
  • OpenSees on NEEShub
  • Getting Started with OpenSees
  • Modeling Diaphragms in 2D
  • OpenSees & Output
  • Force-based Element vs. Displacement-based Element
  • Adding your own code to OpenSees

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The two most commonly used OpenSees elements for modeling beam-column elements are force-based element (FBE) and displacement-based element (DBE). Although OpenSees command for defining these two elements has the same arguments, a beam-column element needs to be modeled differently using these two elements to achieve a comparable level of accuracy. The intent of this seminar is to show users how to properly model beam-column elements with both FBE and DBE. The theory behind these two elements along with two examples will be presented to users to enhance their understanding of the elements and assure their correct application. This seminar covers:

• Introduction
• Theory of force-based element
• Theory of displacement-based element
• Example 1 – steel beam (made up configuration that highlights modeling differences between FBE and DBE elements)
• Example 2 – practical example (bridge RC column)
• Summary and conclusions

PPT presentation of the seminar can be found here:

• FBE vs. DBE

Video of the seminar can be found here:

• FBE vs. DBE

OpenSees files used to demonstrate the effect of rigid constraints can be found here:

• The main file that is to be sourced from the OpenSees interpreter:
  • ConventionalColumn_Cyclic.tcl
• Supporting files to be stored in the same folder with the main file:
  • LibUnits.tcl (define system of units)
  • singlecycle.tcl (procedure for writing one cycle of displacement history)
  • leh415.xls (experimental force-displacement response)