OpenSees Example 7. 3D Frame, 3-story 3-bayX 3-bayZ, Reinforced-Concrete Section & Steel W-Section: Difference between revisions

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As is shown in this example, the reinforced-concrete model using the nonlinearBeamColumn element has difficulties converging at very large lateral deformations.  
As is shown in this example, the reinforced-concrete model using the nonlinearBeamColumn element has difficulties converging at very large lateral deformations.  
A second model is, therefore, included in this example, which uses the Opensees [[Beam With Hinges Element]] element to model the columns. This element is able to achieve convergence at such high lateral-drift levels.
A second model is, therefore, included in this example, which uses the Opensees [[Beam With Hinges Element]] element to model the columns. This element is able to achieve convergence at such high lateral-drift levels.
 
This example also demonstrates the use of pre-packaged display procedures.




Revision as of 21:24, 11 November 2009

Introduction

This example is the first example in a 3D space. The frame in this examples is a 3-story, 3-bay frame in both directions. The columns (elements parallel to Y-direction), beams (elements parallel to X-direction), and girders (elements parallel to Z-direction), are all defined at the section level, one section of each of these types of elements. The sections can either be elastic sections (useful to check elastic properties) or fiber sections. As in the previous frame examples, both reinforced-concrete and steel W-sections are demonstrated in this example. As is shown in this example, the reinforced-concrete model using the nonlinearBeamColumn element has difficulties converging at very large lateral deformations. A second model is, therefore, included in this example, which uses the Opensees Beam With Hinges Element element to model the columns. This element is able to achieve convergence at such high lateral-drift levels. This example also demonstrates the use of pre-packaged display procedures.


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

FiberSection -- Standard AISC W-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.
  • Standard AISC W-section
FiberSection -- Reinforced Concrete 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.
  • Rectangular Reinforced-Concrete Section


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 Ex7.Frame3D.build.ElasticSection.tcl
source Ex7.Frame3D.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 Ex7.Frame3D.build.InelasticSection.tcl 
source Ex7.Frame3D.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 Ex7.Frame3D.build.InelasticFiberSection.tcl
source Ex7.Frame3D.analyze.Dynamic.EQ.bidirect.tcl


Notes

Return to OpenSees Examples Manual -- Structural Models & Analyses

Return to OpenSees User

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