RAM Concept Loading [FAQ]

 Applies To 
 Product(s):RAM Concept
 Area: Modeling
 Original Author:Bentley Technical Support Group

Is pattern loading possible?

Yes, but the user must graphically define the load patterns. Refer to the program manual for further details:

Are area loads additive?

Yes, the program considers the cumulative total of overlapping surface loads.

Note, it is possible to assign loads with negative magnitude which sometimes makes surface load modeling simpler.

Also note, this is opposite to the behavior of surface loads in RAM Structural System where only the top load counts. When you import surface loads from RAM SS into Concept, they are automatically adjusted to be equivalent.

Is self-weight considered?

In Ram Concept Self-weight of the slab mesh is always considered. The weight of the columns and walls above the slab may optionally be considered using the Criteria - Calc options command and checking the General option to "Include supports above slab in self-dead loading"

Just above this is an option to "Create viewable self-dead loading". When this option is on, the Layer - Loading - Self-Dead Loading will include graphics and text for the applied self dead loading once the Calc All process is complete. This can be very slow and somewhat difficult to read due to the amount of data however, so this option is off by default. 

The Calc Log reports the total self-weight as does the Estimate.

How are lateral loads with elevation treated?

Every point, line and surface load in Concept has a property for "Elevation above slab surface" that can place the load above (positive elevation) or below (negative elevation) the slab surface. 

These elevated loads are connected to the slab centroid with vertical rigid links analogous to a stiff flagpole. For an elevated line load it's a series of such links connecting the load to the slab.

Can I make a line load that's triangular or non-uniform?

Yes, when entering the magnitude of the line load, enter two values separated by a comma. For example, if you enter the following properties:

The load you create will linearly vary from 2 k/ft at the first point to 1 k/ft at the end.

You can similarly enter surface loads that slope using three magnitude values separated by commas. Then apply the surface load to any polygon. The first value is associated with the first selected point, the second with the second, the third with the third, and any subsequent point values are calculated based on the slope. 

Why do I get a Analysis Error that says, "Rule Set "Service Design" is being used by load combinations that appear to have load factors set for different purposes.  This is likely an error."

Ram Concept has a hard coded set of load factors for each design code and for each rule set. You can find more about the default load factors in the manual in chapters 54-64 in the second sub-sections for "default load combinations."

When the load combinations are manually altered by the user and the load factors are changed, or when new combinations are added that do not use the expected load factors, then such an error will occur.

If the changes are intentional then the warning can be ignored.

To reset the load combinations to program presets use the Criteria menu option - Rebuild Load Combos...


We recommend saving the file, printing out the current load combinations, then using the Rebuild Load Combinations tool to reset values and finally compare the values when deciding what is best.

Why don't I see any Live Load Reduction?

Refer to the program manual, Chapter 27 "Using Live Load Reduction" and Chapter 52, “Live Load Reduction Notes” for further details.

There are 4 main requirements for Live Load reduction to occur in Ram Concept.

1. A code for LL Reduction must be selected under Criteria - Calc options. There is not a one-to-one association of the design codes and the codes for Live Load reduction, so the program defaults this to "None".

2. The loading type where the loads are modeled must be of a "Reducible" type (including some storage and parking types):

3. The Design Strips, Design Sections, Columns, Walls, and/or Punching Checks which are to have reductions applied must have the Max Live Load Reduction % set to a value greater than 0. When using Specified LLR Parameters, they must also have non zero values for LLR Levels, Trib. Area and Influence area.

4. Finally, Ram Concept does not perform Live Load Reduction on Mat Foundations (as determined by the presence of area springs in the model). 

As noted in Chapter 52, “Live Load Reduction Notes”, the program only applies live load reduction when combinations of loads are at work. The results for individual load cases are given before any reduction has taken place.

In concrete structures, the determination of tributary area and influence area can be rather complicated. Refer to section 52.2 and 52.3 for details on how Ram Concept performs these calculations for Columns, Walls, Punching Checks, Design Strips and individual Design Sections.

See Also

RAM Concept Lateral Self Equilibrium Analysis

Product TechNotes and FAQs

Structural Product TechNotes And FAQs