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. (The current OpenSees display features are limited as their development was halted early on)
Input
Model Building
- The following tasks are performed when building the model
- define units
- define model
- define recorders for output
- define & apply gravity
- The only difference between the two input files is in modelling the element section properties and calculating beam and column weight/mass.
Steel W Section
Files
Notes
- 3D building frame: Steel W sections for both columns and beams. (variable elastic or fiber section)
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RC Section
Files
Notes
- 3D building frame: Reinforced-concrete rectangular sections for both columns and beams. (variable elastic or fiber section)
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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
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Static Reversed Cyclic
Files
Notes
- One-directional displacement-controlled static loading
- Displacement cycles are imposed in positive and negative direction
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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
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Dynamic Uniform Earthquake Ground Motion (typical)
Files
Notes
- Earthquake (from file) acceleration input
- Same acceleration input at all nodes restrained in specified direction
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Dynamic Multiple-Support Sine-Wave Ground Motion
Files
Notes
- Sine-wave displacement input
- Different displacements are specified at particular nodes in specified directions
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Dynamic Multiple-Support Earthquake Ground Motion
Files
Notes
- Earthquake (from file) displacement input
- Different displacements are specified at particular nodes in specified directions
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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
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Run
The model and analysis combinations for this example are numerous. The following are an small subset, for demonstration purposes:
- To run W-Section Model, Static Pushover Analysis:
puts " -------------Elastic Model -------------"
puts " -------------Static Pushover Analysis -------------"
source Ex7.Frame3D.build.Wsec.tcl
source Ex7.Frame3D.analyze.Static.Push.tcl
- To run RC Model, Uniform Earthquake Excitation
puts " -------------Uniaxial Inelastic Section, Nonlinear Model -------------"
puts " -------------Uniform Earthquake Excitation -------------"
source Ex7.Frame3D.build.RCsec.tcl
source Ex7.Frame3D.analyze.Dynamic.EQ.Uniform.tcl
Notes
Return to OpenSees Examples Manual -- Structural Models & Analyses
Return to OpenSees User
