OpenSees Example 6. generic 2D Frame, N-story N-bay, Reinforced-Concrete Section & Steel W-Section

Introduction

• This example utilizes Tcl variable-substitution and array-management tools to optimize the building of the numerical model of a generic 2D frame.
• The number of stories and the number of bays are set as variables, and can, therefore, be changed.
• While this input file requires careful programming, chances of error are reduced because nodes and elements do not have to be defined individually and manually.
• While the number of bays is limited to 9 (this can be changed by modifying the node-numbering scheme), there is no limit to the number of stories.

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 Ex6.genericFrame2D.build.ElasticSection.tcl LibUnits.tcl DisplayPlane.tcl DisplayModel2D.tcl Notes Effective axial and flexural stiffnesses are defined at the element level elasticBeamColumn elements	Distributed Plasticity Element, Uniaxial Section Files Ex6.genericFrame2D.build.InelasticSection.tcl LibUnits.tcl DisplayPlane.tcl DisplayModel2D.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 FiberSection -- Standard AISC W-Section Files Ex6.genericFrame2D.build.InelasticFiberWSection.tcl LibUnits.tcl Wsection.tcl DisplayPlane.tcl DisplayModel2D.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. Standard AISC W-section FiberSection -- Reinforced Concrete Section Files Ex6.genericFrame2D.build.InelasticFiberRCSection.tcl LibUnits.tcl LibMaterialsRC.tcl BuildRCrectSection.tcl DisplayPlane.tcl DisplayModel2D.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. Rectangular Reinforced-Concrete Section

Lateral-Load Analysis

The following tasks are performed in the analysis

• define lateral-load parameters
• analyze

Static Static Pushover Files Ex6.genericFrame2D.analyze.Static.Push.tcl LibAnalysisStaticParameters.tcl Notes One-directional monotonic displacement-controlled static loading Static Reversed Cyclic Files Ex6.genericFrame2D.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 Ex6.genericFrame2D.analyze.Dynamic.sine.multipleSupport.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 Ex6.genericFrame2D.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 Ex6.genericFrame2D.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 Ex6.genericFrame2D.analyze.Dynamic.EQ.multipleSupport.tcl (this file needs to be corrected for displacement input) LibAnalysisDynamicParameters.tcl ReadSMDFileDisp.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 Ex6.genericFrame2D.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 Ex6.genericFrame2D.build.ElasticSection.tcl
source Ex6.genericFrame2D.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 Ex6.genericFrame2D.build.InelasticSection.tcl 
source Ex6.genericFrame2D.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 Ex6.genericFrame2D.build.InelasticFiberSection.tcl
source Ex6.genericFrame2D.analyze.Dynamic.EQ.bidirect.tcl

Notes

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