How can I model continuous foundations?

In RAM Structural System, a continuous foundation can be modeled under walls or columns. Like all foundations, start on the lowest framed level, it is not required to make a separate foundation level in the program. On that level place the foundation using Layout - Foundation - Continuous - Add.

When placing a continuous foundation the user must start and end the foundation at a column or wall end point. If other columns along the foundation are slightly off the center line they can still be considered in the foundation design so long as they fall within the set tolerance.

One problem is when there are too many snaps turned on. When placing continuous foundation, we suggest turning off all snap modes except columns and walls to prevent accidentally snapping to other items on the layout. 

Another problem has to do with walls that are segmented or step down. The program is limited to designing continuous foundations that start where a line of walls starts and end where the line of walls ends. The user cannot place a foundation under part of the length of a wall, even if the wall is segmented. 

Note, the Modeler - Datacheck will give a warning if nothing at all is modeled below the wall (wall 5 above) but this warning can be ignored. The analysis in Ram Frame (or Ram Concrete) will correctly assume a point of support under the wall regardless. You can confirm the vertical reactions under the wall in those modules. 

What other limitations are there for Continuous Footing Design?

1. As noted in the Foundation [FAQ], continuous footings that intersect will each be designed for the full corner reactions. This is especially limiting for long wall footings that intersect.
2. Where door openings exist the foundation module does not consider them, the program only checks sections beyond the wall ends. This could be unconservative for large door openings.
3. Continuous foundation design does not consider out-of-plane moments or moments due to load eccentricity. In-plane shear forces also do not have any effect. Only vertical loads and in-plane moments are considered.

See Also

RAM SS - Foundation [FAQ]