RAMSS Wind Loads [FAQ]
| Applies To | |||
| Product(s): | RAM Structural System | ||
| Version(s): | Any | ||
| Environment: | N/A | ||
| Area: | N/A | ||
| Subarea: | N/A | ||
| Original Author: | Bentley Technical Support Group | ||
How is the wind typically applied to the model?
The slab edge determines the exposure (Ram Frame – Loads – Exposure) and we assume some kind of vertically spanning cladding transfers the loads to the diaphragms. The program calculates a total force based on total exposure, considering one windward surface and one leeward surface per diaphragm. Where the wind may hit more area, user defined loads should be used.
How are the wind pressures viewed?
You can see the total force using Process – Results – Applied Story Forces, or Report the “Loads and Applied Forces” to see the intermediate wind pressure calculations. The Report – “Exposure Boundaries” is useful for visualizing the exposed surfaces of the model.
Is wind uplift considered?
No, the program only applies the total horizontal force for each story or diaphragm. Uplift loads are not yet considered.
While there is no good work around for this limitation some users apply negative magnitude Live Loads in order to check the beams (or foundations) for uplift. It's important to note that the program still sees this as a Live load and factors it accordingly, so some adjustments in the magnitude of the applied load or customization of the load combinations might be required.
How does sloped framing affect the wind loads?
The program currently applies the wind loads based on the simple rectangular area of the structure defined by the story data. Adjustments in the column and wall elevations do not affect the total applied wind loads at this time.
Use the Report - "Exposure Boundaries" to see a visualization of the exposed wind surfaces whenever there is some concern over the height or tributary width being used to calculate total story forces.
Can wind loads on open structures be generated?
No, when the program generates wind loads it always assumes the structure is fully clad all the way down to the ground level with one complete windward and leeward surface.
For any other condition and where rigid diaphragms exist, "User defined story forces" should be used(these.Userdefinedstoryforces are defined in RAM Frame under loadsLoads - loadcases)LoadCasesbyselecting"Userdefinedstoryforces"fromthedropdownmenutotherightofthetoggleforwindloads. When there is no rigid diaphragm use "Nodal loads." (Nodallateralloadsare defined in the Modeler in the Elevation view)view.
The program generated wind loads are not completely accurate for any of the following situations :below.
- open structures,
- partially exposed structures,
- structures with multiple windward surfaces (e.g. a "U" shaped plan),
- structures with a stepping foundation.
- upperportionofastructuremodeledinatwo-stagelateralanalysiswithlowerportionomitted
See Also
Structural Product TechNotes And FAQs
External Links
Bentley Technical Support KnowledgeBase
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