Zachary Otten's Activities

Rhythmic Activity on Floors in RAM Concept

Zachary Otten — Mon, 03 Oct 2022 21:25:35 GMT

I have previously used RAM Concept to analyze slabs for footfall vibration criteria. Is there a guide to using RAM Concept to analyze slabs for rhythmic group loads such as aerobics, dancing, jumping exercises, etc? The slab is a flat plate concrete slab.

RAM Frame Diaphragm Stiffness Clarification

Zachary Otten — Mon, 28 Feb 2022 14:43:42 GMT

I am working on a structure that has a flooring system of 3/4" concrete board spanning between cold-form metal joists at 16" O.C. The joists span up to 20' between wide-flange moment and braced frames. In an effort to simplify the modeling for this multi-story, large structure that is changing through design, I have omitted the joists and spanned the floor in the direction of the joists. My problem is that the floor system is being analyzed as semi-rigid, and the out of plane (vertical) deflections for lateral wind and seismic loads have been very large, 25" - 30". One solution is to model the joists as lateral members, but this will be very time consuming. Is it possible to make this deflection more realistic? I looked into the "Story Diaphragm" option in RAM Frame that includes out of plan stiffness for semi-rigid diaphragms with one-way decks for lateral and gravity load cases, and while this creates the result I expected, I am not sure what the program is doing since the span is still 20' and there are no gravity members joists that I would expect to be able to improve the results to 1/2" of vertical movement. A step that I have considered is using stiffness modifiers to increase the out of plan stiffness, but I am not sure that will lead to the desired outcome and how that may affect other results.

Are Superimposed Dead Loads added to the Mass?

Zachary Otten — Wed, 25 Jul 2018 14:47:07 GMT

Are superimposed dead loads applied in the forms of line, area, and point loads added to the mass in RAM Frame automatically or does the user need to add the dead load into the "Dead Load" AND "Mass Dead Load" dialog?

The following links only describe storage, snow, etc.

https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/3037/ram-ss-gravity-loads-faq

https://communities.bentley.com/products/ram-staad/w/structural_analysis_and_design__wiki/17968/ram-frame-masses

RAM Response Modification Factor

Zachary Otten — Mon, 26 Mar 2018 18:17:52 GMT

When using RAM Frame for a seismic analysis, is it possible to set the response modification factor to a certain value such as 3 in the event that you are using Seismic Force-Resisting System H in ASCE 7-10 Table 12.2-1 which is for "STEEL SYSTEMS NOT SPECIFICALLY DETAILED FOR SEISMIC RESISTANCE, EXCLUDING CANTILEVER COLUMN SYSTEMS." We would like to use 3 instead of the calculated 3.5 given by the program.

Skewed beams not picking up load from slab

Zachary Otten — Fri, 10 Nov 2017 13:21:00 GMT

I have a slab edge following a skewed angle. The slab distributes load to the member running perpendicular to the deck span but not to the skewed beam. Is this a glitch or are there special techniques to distribute loads to skewed beams. I noticed that the skewed beam is picking up the load from the slab overhang.

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Fri, 10 Nov 2017 03:05:04 GMT

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