View source for OpenSees Example 2a. Elastic Cantilever Column with variables

==Introduction==
The objective of this example is to demonstrate the use of variables in defining the OpenSees input.

While the structural model is the same, there are two lateral-load cases:

==Input==

{| style="margin:0; background:none;" 
<!--        Column 1   image     -->
| style="margin:0; width:25%; border:1px solid #ddcef2; background:#white; vertical-align:top; " |
{| style="width:100%; vertical-align:top;background:#white;"
<h3>Static Pushover</h3>
----
|-
| style="color:#000;" | <div>
[[File:Example2a_Push.GIF|link=OpenSees Example 2a. Elastic Cantilever Column with variables]]
----
<strong>Files</strong>
*[[Media:Ex2a.Canti2D.ElasticElement.Push.tcl|Ex2a.Canti2D.ElasticElement.Push.tcl]]
</div>
|}
<!--        Column 2        -->
| style="margin:0; width:25%; border:1px solid #ddcef2; background:#white; vertical-align:top; " |
{| style="width:100%; vertical-align:top;background:#white;"
<h3>Dynamic EQ Ground Motion</h3>
----
|-
| style="color:#000;" | <div>
[[File:Example2a_EQ.GIF|link=OpenSees Example 2a. Elastic Cantilever Column with variables]]
----
<strong>Files</strong>
*[[Media:Ex2a.Canti2D.ElasticElement.EQ.tcl|Ex2a.Canti2D.ElasticElement.EQ.tcl]]
*[[Media:BM68elc.zip|BM68elc.acc]] (ground-motion file)
</div>
|}

|}

==Run==
*To run Static Pushover analysis:
<blockquote><source lang="Tcl">
source Ex2a.Canti2D.ElasticElement.Push.tcl
</source> </blockquote>

*To run EQ ground-motion analysis (BM68elc.acc needs to be downloaded into the same directory):
<blockquote><source lang="Tcl">
source Ex2a.Canti2D.ElasticElement.EQ.tcl
</source> </blockquote>

==Notes==
In this example, all input values for Example 1a are replaced by variables. 

For example, the following series of commands from Example 1a:

<blockquote><source lang="Tcl">
# define GEOMETRY 
# nodal coordinates:
node 1 0 0; 
# node#, X Y
node 2 0 432
</source> </blockquote>

was replace with the following series of commands in Example 2a:
<blockquote>
<source lang="Tcl">
# define GEOMETRY 
set LCol 432; # column length
# nodal coordinates:
node 1 0 0; 
# node#, X, Y
node 2 0 $LCol 
</source> 
</blockquote>
While the use of variables may seem more time consuming in the simple examples, it is very effective in large examples. The following is a list of some of the advantages of using variables:

*Reduced error and easier error checking because values are defined one time only. 
*Easy to change values of model parameters
*Reduced amount of documentation within a file




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Return to [[OpenSees Examples Manual -- Structural Models & Analyses]]

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