# Basic Examples Manual
The objective of this primer is to provide new users of OpenSees
(Open System for Earthquake Engineering Simulation) familiar structural
engineering examples as a convenient method for learning how to use the
software.
To conduct a simulation in OpenSees, the user creates an input file
(a script). A script is just a series of commands that instruct the
interpreter what to do. In the case of OpenSees, the commands either
create objects or invoke methods (procedures) on those objects. In
OpenSees there are 3 types of objects the user must create:
- Modeling: The user first creates a ModelBuilder object which defines
the type of model, and commands available for building the model. With a
ModelBuilder defined the user then creates the Element, Node,
LoadPattern and Constraint objects that define the model. In this primer
the use of the basic ModelBuilder will be demonstrated.
- Analysis: After the user has defined the model, the next step is to
create the Analysis object for analyzing the model. This may be a simple
static linear analysis or a transient non-linear analysis. In OpenSees,
an Analysis object is composed of several component objects and these
define the type of analysis that is performed. The component objects
consist of the following: SolutionAlgorithm, Integrator,
ConstraintHandler, DOF Numberer, SystemOfEqn, Solver, and
ConvergenceTest. This approach provides a great deal of flexibility in
how an analysis is conducted, but requires knowledge on behalf of the
user as to what the different options provide.
- Output Specification: Once the model and analysis have been defined,
the user must specify what is to be monitored during the analysis.
OpenSees by default will producde no output. The outputs specified could
for example be the displacement history at a node or internal stress
state at some material point in an element element. The user typically
creates Recorder objects to store what the user wants to examine, though
the user can also use the tcl puts command.
In each of the following examples, tcl scripts are used to create
model, analysis and a recorder objects. After these objects have been
created, the analysis is performed. The analyses performed on these
models consist of simple static gravity analysis and pushover analysis
and transient analysis of models subjected to earthquake excitation. The
examples are not meant to be completely realistic, but they are
representative of typical structures. They are intended to remain s
- Truss
Example
- Moment
Curvature Example
-
Reinforced Concrete Portal Frame Example
- Reinforced Concrete Portal Gravity Analysis
- Reinforced Concrete Portal Pushover Analysis
- Reinforced Concrete Portal Earthquake
Analysis
- Elastic Frame
Example
- Steel Frame
Example
- Simply supported beam modeled with two dimensional
solid elements
- Time History Analysis of a 2D Elastic Cantilever
Column
- Eigen analysis of a two-story shear frame
- Eigen analysis of a two-storey one-bay frame