Introductory example

Objectives and Characteristics

Model Types

Analysis Types

Example 1a. Elastic Cantilever Column

• overview of basic OpenSees input structure
• coordinates, boundary conditions, element connectivity, nodal masses, nodal loads, etc.
• two-node, one element

• elastic elements

• static pushover analysis
• dynamic earthquake-input analysis

Example 1b. Elastic Portal Frame

• two element types
• distributed element loads

• elastic elements

• static pushover analysis
• dynamic earthquake-input analysis

Simple Nonlinear Analysis Example

Objectives and Characteristics

Model Types

Analysis Types

Example 2a. Elastic Cantilever Column with variables

• introduce variable: define & use

• elastic element

• static pushover analysis
• dynamic earthquake-input analysis

Example 2b. Nonlinear Cantilever Column: Uniaxial Inelastic Section

• first example of nonlinear model, set nonlinearity at section level

• nonlinearBeamColumn element
• uniaxial section

• static pushover analysis
• dynamic earthquake-input analysis

Example 2c. Nonlinear Cantilever Column: Inelastic Uniaxial Materials in Fiber Section

• set nonlinearity at material level
• material stress-strain response is assembled into fiber section
• reinforced-concrete fiber section

• nonlinearBeamColumn element
• uniaxial material
• fiber section (Reinforced-concrete fiber section)

• static pushover analysis
• dynamic earthquake-input analysis

2D Structural Modelling & Analysis Examples

Objectives and Characteristics

Model Types

Analysis Types

Example 3. Cantilever Column with units

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

• elastic elements
• inelastic uniaxial section
• fiber section (Reinforced-concrete fiber section)
• Linear, PDelta or Corotational Transformation

• static pushover analysis
• dynamic earthquake-input analysis (uniform excitation)

Example 4. Portal Frame

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

• elastic elements
• inelastic uniaxial section
• inelastic fiber section (Reinforced-concrete fiber section)

• static pushover analysis
• static reversed cyclic analysis
• dynamic sine-wave input analysis (uniform excitation)
• dynamic earthquake-input analysis (uniform excitation)
• dynamic sine-wave input analysis (multiple-support excitation)
• dynamic earthquake-input analysis (multiple-support excitation)
• dynamic bidirectional earthquake-input analysis (uniform excitation)

Example 5. 2D Frame, 3-story 3-bay, Reinforced-Concrete Section & Steel W-Section

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

• Reinforced-Concrete Section
• Steel W-Section
• elastic uniaxial section
• inelastic uniaxial section
• inelastic fiber section

• static pushover analysis
• static reversed cyclic analysis
• dynamic sine-wave input analysis (uniform excitation)
• dynamic earthquake-input analysis (uniform excitation)
• dynamic sine-wave input analysis (multiple-support excitation)
• dynamic earthquake-input analysis (multiple-support excitation)
• dynamic bidirectional earthquake-input analysis (uniform excitation)

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

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

• Reinforced-Concrete Section
• Steel W-Section
• elastic uniaxial section
• inelastic uniaxial section
• inelastic fiber section

• static pushover analysis
• static reversed cyclic analysis
• dynamic sine-wave input analysis (uniform excitation)
• dynamic earthquake-input analysis (uniform excitation)
• dynamic sine-wave input analysis (multiple-support excitation)
• dynamic earthquake-input analysis (multiple-support excitation)
• dynamic bidirectional earthquake-input analysis (uniform excitation)

3D Structural Modelling & Analysis Examples

Objectives and Characteristics

Model Types

Analysis Types

Example 7. 3D Frame, 3-story 3-bayX 3-bayZ, Reinforced-Concrete Section & Steel W-Section

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

• Reinforced-Concrete Section
• Steel W-Section
• Elastic or Fiber Section option is a variable within one input file
• rigid diaphragm

• static pushover analysis
• static reversed cyclic analysis
• dynamic sine-wave input analysis (uniform excitation)
• dynamic earthquake-input analysis (uniform excitation)
• dynamic sine-wave input analysis (multiple-support excitation)
• dynamic earthquake-input analysis (multiple-support excitation)
• dynamic bidirectional earthquake-input analysis (uniform excitation)

Example 8. generic 3D Frame, NStory NBayX NBayZ, Reinforced-Concrete Section & Steel W-Section

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

• Reinforced-Concrete Section
• Steel W-Section
• Elastic or Fiber Section option is a variable within one input file optional rigid diaphragm
• rigid diaphragm

• static pushover analysis
• static reversed cyclic analysis
• dynamic sine-wave input analysis (uniform excitation)
• dynamic earthquake-input analysis (uniform excitation)
• dynamic sine-wave input analysis (multiple-support excitation)
• dynamic earthquake-input analysis (multiple-support excitation)
• dynamic bidirectional earthquake-input analysis (uniform excitation)

Section Modelling And Analysis

Example 9. Build & Analyze a Section

• defined section using uniaxial behavior (define moment-curvature curve) or
• define section using uniaxial materials (define stress curve) in fiber section

2D & 3D models of sections:

• Uniaxial Nonlinear section
• Fiber Steel W-section
• Fiber RC symmetric rectangular unconfined-concrete section
• Fiber RC symmetric rectangular unconfined & confined-concrete section
• Fiber RC generalized rectangular section
• Fiber RC generalized circular section

• 2D & 3D static unidirectional moment-curvature analysis