OpenSees Example 4. Portal Frame

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Introduction

This is a great example! To all the demonstrations that Example 3 has done, Example 4 adds the use of previously-defined Tcl procedures (a procedure is a Tcl command that is created by the proc command) or scripts. This example also introduces new kinds of static and dynamic analyses.


Input

Model Building

The following tasks are performed when building the model

  • define units
  • define model
  • define recorders for output
  • define & apply gravity

Elastic Element



Files


Notes

  • Effective axial and flexural stiffnesses are defined at the element level
  • elasticBeamColumn elements

Distributed Plasticity Element, Uniaxial Section



Files


Notes

  • Axial and flexural stiffnesses/strength are defined independently at the section level
  • uniaxial inelastic section (moment-curvature)
  • nonlinear beam-column elements

Distributed Plasticity Element, Fiber Section



Files


Notes

  • The section is broken down into fibers where uniaxial materials are defined independently.
  • The program calculates flexural and axial stiffnesses/strength by integrating strains across the section.
  • fiber section
  • nonlinear beam-column elements


Lateral-Load Analysis

The following tasks are performed in the analysis

  • define lateral-load parameters
  • analyze

Static

Static Pushover


Files


Notes

  • One-directional monotonic displacement-controlled static loading

Static Reversed Cyclic


Files


Notes

  • One-directional displacement-controlled static loading
  • Displacement cycles are imposed in positive and negative direction

Dynamic EQ Ground Motion

Dynamic Uniform Sine-Wave Ground Motion


Files


Notes

  • Sine-wave acceleration input
  • Same acceleration input at all nodes restrained in specified direction

Dynamic Uniform Earthquake Ground Motion (typical)


Files


Notes

  • Earthquake (from file) acceleration input
  • Same acceleration input at all nodes restrained in specified direction

Dynamic Multiple-Support Sine-Wave Ground Motion


Files


Notes

  • Sine-wave displacement input
  • Different displacements are specified at particular nodes in specified directions

Dynamic Multiple-Support Earthquake Ground Motion


Files


Notes

  • Earthquake (from file) displacement input
  • Different displacements are specified at particular nodes in specified directions

Dynamic Bidirectional Earthquake Ground Motion (typical)


Files


Notes

  • Earthquake (from file) acceleration input
  • Different ground motion in two directions
  • Same acceleration input at all nodes restrained in specified direction

Run

The model and analysis combinations for this example are numerous. The following are an small subset, for demonstration purposes:

  • To run Elastic Mode, Static Pushover Analysis:
puts " -------------Elastic Model -------------"
puts " -------------Static Pushover Analysis -------------"
source Ex4.Portal2D.build.ElasticElement.tcl
source Ex4.Portal2D.analyze.Static.Push.tcl
  • To run Uniaxial Inelastic Section, Nonlinear Model, Uniform Earthquake Excitation
puts " -------------Uniaxial Inelastic Section, Nonlinear Model -------------"
puts " -------------Uniform Earthquake Excitation -------------"
source Ex4.Portal2D.build.InelasticSection.tcl 
source Ex4.Portal2D.analyze.Dynamic.EQ.Uniform.tcl
  • To run Uniaxial Inelastic Material, Fiber Section, Nonlinear Model, Dynamic Bidirectional Earthquake Ground Motion
puts " -------------Uniaxial Inelastic Material, Fiber Section, Nonlinear Model -------------"
puts " -------------Dynamic Bidirectional Earthquake Ground Motion  -------------"
source Ex4.Portal2D.build.InelasticFiberSection.tcl
source Ex4.Portal2D.analyze.Dynamic.EQ.bidirect.tcl


Notes


Return to OpenSees Examples Manual -- Structural Models & Analyses

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