Example Description
This example uses a simply supported beam on elastic foundation to test this model frame line spring assignment. The beam is 36 inches wide by 36 inches deep, 15 feet long and the soil subgrade modulus is 800 k/ft3. A 500 kip vertical load is applied at the center of the beam and the self weight of the beam is ignored. The moment and deflection at the center of the beam are compared with independent results calculated using formulas presented in Timoshenko 1956.
The model is made up of two frame objects each 7.5 feet long. Three separate models are created. The models are identical, except for the discretization of the two frame objects. Models A, B and C discretize each frame object into 1, 4 and 100 frame elements respectively.
Important Note: Only bending deformations are considered in the analysis. Shear and axial deformations are ignored. In this model, this is achieved by setting the property modification factor for area to 1,000 and setting the property modification factor for shear area to 0.
Tested Features
- Frame line spring assignments
- Static analysis of beam on elastic foundation
- Automatic frame subdivision
App
Object Link: https://openbrim.org/objid8sqk2m0z0u9jgo83sqsrfp.project
Library
Object Link: https://openbrim.org/objidsiz6u2scfqgqn0uzb0vkp.libobj
Model | #Elms. | Output Parameter | OpenBrIM | SAP2000 | Independent | Percent Difference (SAP2000 vs Independent) | Percent Difference (OpenBrIM vs Independent) |
|---|---|---|---|---|---|---|---|
B | 4 | Uz (jt 2) in | -0.08933 | -0.08933 | -0.08933 | 0% | 0% |
| My (jt 2) k-in | 17,434.50164 | 17,634 | 17,698 | -0.36% | 0% | ||
C | 100 | Uz (jt 2) in | −0.08933 | -0.08933 | -0.08933 | 0% | 0% |
| My (jt 2) k-in | 17,698 | 17,698 | 17,698 | 0% | 0% |
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