OpenSees Example 4. Portal Frame

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 Ex4.Portal2D.build.ElasticElement.tcl LibUnits.tcl Notes Effective axial and flexural stiffnesses are defined at the element level elasticBeamColumn elements

Distributed Plasticity Element, Uniaxial Section Files Ex4.Portal2D.build.InelasticSection.tcl LibUnits.tcl 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 Ex4.Portal2D.build.InelasticFiberSection.tcl LibUnits.tcl 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 Ex4.Portal2D.analyze.Static.Push.tcl LibAnalysisStaticParameters.tcl Notes One-directional monotonic displacement-controlled static loading Static Reversed Cyclic Files Ex4.Portal2D.analyze.Static.Cycle.tcl LibAnalysisStaticParameters.tcl LibGeneratePeaks.tcl 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 Ex4.Portal2D.analyze.Dynamic.sine.Uniform.tcl LibAnalysisDynamicParameters.tcl Notes Sine-wave acceleration input Same acceleration input at all nodes restrained in specified direction Dynamic Uniform Earthquake Ground Motion (typical) Files Ex4.Portal2D.analyze.Dynamic.EQ.Uniform.tcl LibAnalysisDynamicParameters.tcl ReadSMDFile.tcl H-E12140.AT2 Notes Earthquake (from file) acceleration input Same acceleration input at all nodes restrained in specified direction Dynamic Multiple-Support Sine-Wave Ground Motion Files Ex4.Portal2D.analyze.Dynamic.sine.multipleSupport.tcl (this file may need to be corrected for displacement input) LibAnalysisDynamicParameters.tcl Notes Sine-wave displacement input Different displacements are specified at particular nodes in specified directions Dynamic Multiple-Support Earthquake Ground Motion Files Ex4.Portal2D.analyze.Dynamic.EQ.multipleSupport.tcl (this file needs to be corrected for displacement input) LibAnalysisDynamicParameters.tcl ReadSMDFile.tcl H-E12140.DT2 (Displacement recording) Notes Earthquake (from file) displacement input Different displacements are specified at particular nodes in specified directions Dynamic Bidirectional Earthquake Ground Motion (typical) Files Ex4.Portal2D.analyze.Dynamic.EQ.bidirect.tcl LibAnalysisDynamicParameters.tcl ReadSMDFile.tcl (need to modify ReadSMDFile.tcl for displacement data) H-E12140.AT2 H-E01140.AT2 (acceleration recording in perpendicular direction) 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

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