"Other" material stiffness in RAM SS

Question

"Other" material stiffness in RAM SS

Whiffle (Structural)

(OP)

8 May 08 14:13

I'm doing a 1 story steel structure with CMU shear walls on 1 side of the building, and a steel braced frame on the other side of the building.

I'm trying to check the lateral load distribution between my shear walls and braced frame.

I've modeled the CMU shear walls with the "other" material using the properties of the masonry. Then I changed the shear walls to "concrete" with all the same CMU properties and a cracked factor of 1.0, and the lateral load distribution between my shear walls and braced frame changed. (I did not touch the braced frame)

I've tried changing the cracked factor to 0.35 and 0.70, but I still can't replicate the results I got from using the "other" material. Does anyone have any suggestions?

strguy11 (Structural) · Answer 1 · 2008-05-12 21:17:23

I think you have to look at the E values as well. I think RAM internally calculates the E. Did you account for this??

Unless you are using RAM V 12, Ram models the diaphragms as rigid. Make sure you really have a rigid diaphragm before using RAM. The new version 12 has a "psuedo rigid" diaphragm that you can use to get loads based on a trib analysis.

1mitchsklar1 (Structural) · Answer 2 · 2008-05-16 07:50:24

forget the E,.35, .7 and concrete. Put the masonry wall in as required (with appropriate prop) and change it to lateral. In Ram Frame set up frame numbers and you will be able to see the load distribution.

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"Other" material stiffness in RAM SS