<?xml version="1.0" encoding="utf-8"?>
<html>
{{Test Problem
name = Line and area springs |
description = Demonstration of line and area springs. |
keyword = spring; line spring; area spring |
program = SAP2000 |
version = na |
status = done |
id = ok/springs - line and area}} |
Overview
When [line spring] or [area springs] are assigned to an object, SAP2000 automatically generates equivalent joint springs at each joint created by [migration1d:automeshing] of such object. Stiffness of these joint springs is determined from the stiffness of the line or area spring assigned to the object and the tributary area for each joint spring (joint springs supporting interior joints are stiffer than the joint springs supporting corner joints). Since the contact pressure would be proportional to the deformation of these joint springs or to the displacement of joints to which these joint springs are attached, you can obtain the contact pressure by multiplying the displacements (that can be readily output both graphically and in a tabular format) by a constant related to the spring stiffness. I have attached a simple model that illustrates this. Below are few more comments and screenshots from the attached model that you may find useful.
In the attached model, I would recommend you to review UZ displacements for "SPRING-LOAD" load case. You will find that the displacements are consistent with the applied loads and stiffness assigned to the area and line springs.
Screenshots
Link/Support Property Data - Explanation of "Factors For Line, Area and Solid Springs"
Area spring and automesh assignment to an area object
Display of equivalent joint springs created by the program to represent line and area springs assigned to an object
Using "View > Set Display Options > Show Analysis Model" menu command, you can display the equivalent joint springs created by the program for an area spring → 
Attachments
File | filename = Springs line and area V12.0.0.zip | title = Springs line and area V12.0.0.zip(Zipped SDB file, 12 kB)
</html>