RAM Drift Module

[Galambos]

I was wondering if anyone had any experience with the RAM Drift Module. We plan on buying it to use it for 14+ story buildings. Please share your thoughts.

 

[WillisV]

Galambos - that module is based upon a displacement participation factor method (energy based method) developed by Finley Charney at VT which pinpoints which members are contributing most heavily to the drift of a building. These "displacement factors" can be broken down into overall displacement (axial/shear/flexural etc) or shown by each of the different components.

RAM requires the user to setup virtual load cases for each and every direction and story that deflection is to be considered. This seems to be a lot of extra work, and I cannot imagine that it would be extremely useful or efficient as opposed to just the engineering judgement approach of looking at the deflections of the building and increaseing beam then column sizes to control drift - BUT I have never used it so maybe it is great.

 

[Boiler8019]

Dont do it! General consensus here is RAM is on its way out. Look into the real FE programs out there. ETABS for one.

 

[271828]

FWIW, the same displacement participation factor method that WillisV (Hey, are you a VT grad, by chance?) is also included in SAP2000 and ETABS.

I've used this stuff before and have found it to only be marginally better than just using engineering judgment. It CAN be useful, but there are also lots of times when it gives nonsensical answers. There are so many design constraints, like wanting equal depth members, etc., that a lot of engineering judgment is still required.

Strangely enough, I think one can do pretty well by just using all small members in the moment frames for the first try. Look at the strength ratios (all will be no good by a wide margin) to get a very rough idea of what's doing the work. Then bump members up from there, using engineering judgment.

 

[Galambos]

thanks for your comments.

Boiler, ive never heard ram was on its way out. im curious, where does that come from?