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Introduction
The examples in this manual are listed in order of simplicity.
NOTE: gravity analysis is always included as part of the model building
Models
The following types of models are represented in these examples:
Elastic Elements
 OpenSees Elastic Beam Column Element
 The elastic, uncoupled, axial and flexural stiffnesses are defined at the element level
 user specifies: E,I,A
Inelastic Elements
 OpenSees ForceBased BeamColumn Element
 Two types of sections
Uniaxial Section
 The inelastic, uncoupled, axial and flexural stiffnesses are defined at the section level
 The OpenSees Uniaxial Section Command is used
 User specifies:
 Axial stiffness A
 Section MomentCurvature characteristics via the OpenSees UniaxialMaterial Command
Fiber Section
 The section is broken down into fibers where uniaxial materials are defined independently.
 The program calculates the coupled flexural and axial stiffnesses/strength by integrating strains across the section
 The OpenSees Fiber Section Command is used
 User specifies
 StressStrain characteristics via the OpenSees UniaxialMaterial Command for all number of materials
 Section geometry via series of Patches and Layers in the fiber section
 Two Section Geometries are presented
 *RC Rectangular Section
 *Standard AISC W section
Lateral Loads
The following types of lateral loads are represented in these examples:
Static Pushover
 Control node is located at the highest floor
 Lateralload distribution is proportional the the mass distribution along the height of the building
 Static analysis
 Two types
Monotonic Pushover
 Onedirectional displacementcontrolled static lateral loading
Reversed Cyclic Pushover
 Onedirectional displacementcontrolled static lateral loading
 Displacement cycles are imposed in positive and negative direction
TimeDependent Dynamic Loads
 Transient analysis
 Four types
Uniform SineWave
 Sinewave acceleration input
 Same acceleration input at all nodes restrained in specified direction
MultipleSupport SineWave
 Sinewave displacement input
 Different displacements are specified at particular nodes in specified directions
Uniform Earthquake
 Earthquake (from file) acceleration input
 Same acceleration input at all nodes restrained in specified direction
MultipleSupport Earthquake
 Earthquake (from file) displacement input
 Different displacements are specified at particular nodes in specified direction
Bidirectional Earthquake
 Different inputs are specified for two directions
 Same acceleration input at all nodes restrained in specified direction
Simulation Process
Each example script does the following:
Build the model
 model dimensions and degreesoffreedom
 nodal coordinates
 nodal constraints  boundary conditions
 nodal masses
 elements and element connectivity
 recorders for output
Define & apply gravity load
 nodal or element load
 staticanalysis parameters (tolerances & load increments)
 analyze
 hold gravity loads constant
 reset time to zero
Define and apply lateral load
 load pattern (nodal loads for static analysis, support ground motion for earthquake)
 lateralanalysis parameters (tolerances & displacement/time increments)
 Static LateralLoad Analysis
 define the displacement increments and displacement path
 Dynamic LateralLoad Analysis
 define the input motion and all associated parameters, such as scaling and input type
 define analysis duration and time increment
 define damping
 analyze
Introductory Examples
The objective of Example 1a and Example 1b is to give an overview of inputfile format in OpenSees using simple scripts.
These scripts do not take advantage of the Tcl scripting capabilities shown in the later examples. However, they do provide starting a place where the input file is similar to that of more familiar FiniteElement Analysis software. Subsequent examples should be used as the basis for user input files.


Objectives

 overview of basic OpenSees input structure
 coordinates, boundary conditions, element connectivity, nodal masses, nodal loads, etc.
 twonode, one element



Analyses

 static pushover
 dynamic earthquakeinput




Objectives

 two element types
 distributed element loads



Analyses

 static pushover
 dynamic earthquakeinput


Simple Examples of NonlinearModels


Objectives

 introduce variable: define & use



Analyses

 static pushover
 dynamic earthquakeinput




Objectives

 first example of nonlinear model, set nonlinearity at section level


Models

 nonlinearBeamColumn element
 uniaxial section


Analyses

 static pushover
 dynamic earthquakeinput




Objectives

 set nonlinearity at material level
 material stressstrain response is assembled into fiber section
 reinforcedconcrete fiber section


Models

 nonlinearBeamColumn element
 uniaxial material
 fiber section (Reinforcedconcrete fiber section)


Analyses

 static pushover
 dynamic earthquakeinput


2D Structural Modeling & Analysis Examples
These examples take advantage of the Tcl scripting language starting from simple variable substitutions in the initial examples, to the more advanced techniques of array management and logical expressions (ifthen statements).


Objectives

 units, defined and used (they will be used in all subsequent examples)
 separate modelbuilding and analysis files
 introduce PDelta effects (or not)


Models

 elastic elements
 inelastic uniaxial section
 fiber section (Reinforcedconcrete fiber section)
 Linear, PDelta or Corotational Transformation


Analyses

 static pushover
 dynamic earthquakeinput




Objectives

 use previouslydefined procedures to simplify input
 introduce more analysis types
 introduce procedure to read database input motion files (data with text in first lines)


Models

 elastic elements
 inelastic uniaxial section
 inelastic fiber section (Reinforcedconcrete fiber section)


Analyses

 static reversed cyclic analysis
 dynamic sinewave input analysis (uniform excitation)
 dynamic earthquakeinput analysis (uniform excitation)
 dynamic sinewave input analysis (multiplesupport excitation)
 dynamic earthquakeinput analysis (multiplesupport excitation)
 dynamic bidirectional earthquakeinput analysis (uniform excitation)




Objectives

 2D frame of fixed geometry: 3story, 3bay
 nodes and elements are defined manually, one by one


Models

 ReinforcedConcrete Section
 Steel WSection
 elastic uniaxial section
 inelastic uniaxial section
 inelastic fiber section


Analyses

 static reversed cyclic analysis
 dynamic sinewave input analysis (uniform excitation)
 dynamic earthquakeinput analysis (uniform excitation)
 dynamic sinewave input analysis (multiplesupport excitation)
 dynamic earthquakeinput analysis (multiplesupport excitation)
 dynamic bidirectional earthquakeinput analysis (uniform excitation)




Objectives

 2D frame geometry of variable geometry ( # stories and # bays are variables)
 node and element definition is automated
 use previouslydefined procedures to view model node numbers and elements, deformed shape, and displacement history, in 2D


Models

 ReinforcedConcrete Section
 Steel WSection
 elastic uniaxial section
 inelastic uniaxial section
 inelastic fiber section


Analyses

 static reversed cyclic analysis
 dynamic sinewave input analysis (uniform excitation)
 dynamic earthquakeinput analysis (uniform excitation)
 dynamic sinewave input analysis (multiplesupport excitation)
 dynamic earthquakeinput analysis (multiplesupport excitation)
 dynamic bidirectional earthquakeinput analysis (uniform excitation)


3D Structural Modeling & Analysis Examples
A few items are new in 3D:
 Additional coordinates need to be considered in defining nodes
 Additional degrees of freedom need to be considered in defining the following:
 nodal constraints (boundary conditions)
 nodal masses
 nodal loads
 The transformation from local element/section coordinates to global system coordinates needs to be specified
 Element loads are specified in local coordinates
 Additional arguments are required for many elements (bending about localy axis) properties
 Element/Section torsional stiffness needs to be considered
 Rigid floor diaphragms need be included for building models


Objectives

 3D frame of fixed geometry
 nodes and elements are manually manually, one by one
 introduce rigid floor diaphragm
 use previouslydefined procedures to view model node numbers and elements, deformed shape, and displacement history, in 3D


Models

 ReinforcedConcrete Section
 Steel WSection
 Elastic or Fiber Section option is a variable within one input file
 rigid diaphragm


Analyses

 static reversed cyclic analysis
 dynamic sinewave input analysis (uniform excitation)
 dynamic earthquakeinput analysis (uniform excitation)
 dynamic sinewave input analysis (multiplesupport excitation)
 dynamic earthquakeinput analysis (multiplesupport excitation)
 dynamic bidirectional earthquakeinput analysis (uniform excitation)




Objectives

 3D frame geometry of variable geometry ( # stories and # bays in X and Z are variables)
 node and element definition is automated
 introduce userinput interface, the user is given the option as to what to view in model


Models

 ReinforcedConcrete Section
 Steel WSection
 Elastic or Fiber Section option is a variable within one input file
 optional rigid diaphragm


Analyses

 static reversed cyclic analysis
 dynamic sinewave input analysis (uniform excitation)
 dynamic earthquakeinput analysis (uniform excitation)
 dynamic sinewave input analysis (multiplesupport excitation)
 dynamic earthquakeinput analysis (multiplesupport excitation)
 dynamic bidirectional earthquakeinput analysis (uniform excitation)


Section Modeling And Analysis Examples


Objectives

 defined section using uniaxial behavior (define momentcurvature curve) or
 define section using uniaxial materials (define stressstrain curve) in fiber section


Models

 Uniaxial Nonlinear section
 Fiber Steel Wsection
 Fiber RC symmetric rectangular unconfinedconcrete section
 Fiber RC symmetric rectangular unconfined & confinedconcrete section
 Fiber RC generalized rectangular section
 Fiber RC generalized circular section


Analyses

 2D static unidirectional momentcurvature analysis
 3D static unidirectional momentcurvature analysis


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