A-03 (Beam on Grade) |
  
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A-03 (Beam on Grade) |
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Objective
To verify the behavior of the line spring
Problem Description
A 300 in beam is supported on an elastic foundation and subjected to a point force of -40,000 lb at the middle as shown below [Ref 1]:
Material properties: E = 29,000 ksi, ν = 0.3
Section properties: Iz =125.8 in4, A = 1 in2
Elastic line spring constant: Ky = 1500 lb / in2
Finite Element Model
20 beam elements
Model type: 2D Frame
Results
The displacement and moment at the middle of the span are given in [Ref 1].
Units: displacement – in; moment – kip-in
@ middle of the span |
ENERCALC 3D |
[Ref 1] |
Displacement Dy |
-0.239 |
-0.238 |
Moment Mz |
544.44 |
547 |
Comments
1. The results given by ENERCALC 3D are very close to the referenced values.
2. Line springs may be replaced by equivalent nodal springs or even truss elements with appropriate section properties as indicated in [Ref 1].
Reference
[1]. McGuire, Gallagher and Ziemian, “Matrix Structural Analysis” 2nd Edition, pp87, John Wiley & Sons, Inc., 2000
