How can I evaluate an existing composite beam?

Using the Process - View/Update command, select the beam in the model. Change the selected member size, set the stud number to the desired value and click Analyze. Then click Update Database when finished.

If the existing stud count is insufficient to achieve 25% composite action (or the code minimum), go to Criteria - Stud Criteria and for the last option, select to "Use Composite section properties".

Note: the program will never optimize a member with less than 25% composite action (US codes), but you can reduce the number of studs and evaluate this way.

Can I lock or freeze all the beam designs?

Yes, once the designs are correct, use the Process - Freeze Design command to freeze the designs for some or all of the beams. This is often a good idea once construction documents for the project have been released.

The same command can be found in other modules, too.

Why are my composite beams being designed as non-composite members?

Beams that have been defined as composite, may be designed as non-composite for the following reasons:

• Non-composite deck
• Opening or exposed beam 
• Cantilever 
• No load

Non-composite deck: Composite beams will be designed as non-composite if the deck on both sides of the beam is non-composite for any portion of the beam span.

Opening or exposed beam: A beam that spans through an opening or penetration or for which there is a portion supporting no deck, such as an inset beam, will be designed as non-composite. Some times it is desired to design inset beams as composite. In order to do this, you can add a short beam from the column to the perimeter beams at an angle (say 45 degrees). Then define the slab edge so that it follows along these short beams, going out and around the perimeter column. That way, the entire beam is covered by the deck and it can be designed as composite (see below).

Cantilever: If the negative bending moment at the support of a cantilever beam is greater than twice the positive moment of the back span, the beam will be designed as non-composite. When a cantilever beam is designed compositely, the program determined number of studs should all be placed in the back-span. Note, for some codes no negative moment is allowed for composite beam design and in those cases a cantilever will always result in non-composite design.

No Load: If there is no load on the beam it will be designed as non-composite. This is sometimes a result of accidentally orienting the deck in the wrong direction such that the infill beams are not loaded.

Note: once a beam has been designed as a non-composite member, the composite flag for the beam will be set to non-composite. You have to go back to the Modeler and use the Layout - Beams - Change properties command to turn it back into a composite member.

Why is the unbraced length reported less than the maximum unbraced length?

The program evaluates bending for each of the various unbraced segments of a beam along with the maximum moments in that segment. The design might be controlled by a shorter unbraced segment with larger moments, or it might be controlled by a longer unbraced segment with smaller moments.

The design report shows the critical condition and indicates where from the left end the critical case occurs.

Can I turn off the pattern loading on beam cantilevers?

Regretfully, not at this time. Live loads are always considered to act on the cantilever only, on the back-span only, or on the entire beam, whichever condition provides the most conservative design for shear, bending and deflection. This is true even for snow loads which can be overly conservative. [[RAM Steel Beam Pattern Loading]] has further details.

Only dead loads are not subject to patterning.

Can I customize the load combinations used in RAM Steel Beam?

Regretfully, not at this time. The load combinations used in RAM Steel are internal to the program and cannot be modified.

See Section 10.3.11 in the RAM Steel Beam Manual for a list of combinations used for each design code.

Note that floor live load and snow or roof live loads are combined and applied as a single live load. Some building codes, such as IBC, permit a reduction (0.75 factor) for combinations including two or more transient loads. RAM Steel uses the combination 1.0 DL + 1.0 LL (effectively, 1.0 DL + 1.0 LL + 1.0 SL). Using the reduction noted above, a load combination of 1.0 DL + 0.75 LL + 0.75 SL is permitted. If the IBC is selected for the code for load combination generation in RAM Frame, 1.0 DL + 0.75 LL + 0.75 SL and not 1.0 DL + 1.0 LL + 1.0 SL. This can cause some design differences for beams designed in RAM Steel Beam versus RAM Frame. 

Can I override the unbraced length of a steel gravity beam?

In cases where you want the unbraced length to be reduced you can add brace points in the Modeler using Layout - Beams - Brace points. Alternatively adding additional short beams framing into the beam in question will brace the top and bottom flange at those locations. Use joists where you want only the top flange braced.

In cases where you want the program to use a longer unbraced length, for example where a beam is set higher than the deck in reality, set the Criteria - Design Criteria - Unbraced length so that neither deck perpendicular nor parallel to the beam braces the top flange. Since it's a global criteria it will affect all beams, however, so you might have to set the criteria this way and check the one beam, freeze the design, and then check the rest using the preferred criteria.

Alternatively, you could add a long penetration (Modeler - Layout - Slab - Slab Penetrations) along the beam covering most of the span.

How can I use a section that does not appear in the View/Update list?

The sections listed in the Steel Beam View/Update dialog box are based on those in the Steel Beam Design Table. See RAM Table Editing for details.

See Also

[[RAM SS - Steel Beam Deflection and Camber]]

[[structural_analysis_and_design__wiki:RAMSS Design Fy or Py|RAMSS Design Fy or Py]]