In SAFE: What is the suitable design strip's width to calculate wide beam shear in Mat foundat

[mhdhamood]

Dears ;
An important issue that because SAFE is Finite element Program, the values of shear & Moment when averaged to small width the result will be larger than when averaging to large widths. The problem for me: What width shall be used for Vu calculation or Mu ...especially when staggered columns are in the Mat ..
1. Shall the width of strip= frame width when columns at the same line. And for Mu we have to divide for column& middle strips.
2. If staggered columns were found , then what width of strip shall be taken to calculate wide beam shear ..And what also the width to consider Mu.

with best wishes

 

[JoshPlumSE]

Does SAFE not have any help files or web resources to help?

Here is a link to the RISAFoundation help file that discusses the topic a bit. You probably have to scroll down a bit until you get to the "setting the width of of the design strip" sub-topic.

In that help file, we reference three other documents:
1) ACI 318 section 13.2
2) A PTI publication titled "Design Fundamentals of Post-Tensioned Concrete Floor".
3) a NEHRP document GCR 12-917-22 titled Seismic Design of Reinforced Concrete Mat Foundations.

Based on your description, I would think the PTI method (which we call the zero shear transfer method) may be the most appropriate choice for your foundation. But, the choice is really yours based on your engineering judgment.

 

[JoshPlumSE]

Sorry, the direct link doesn't behave nicely with the forum's formatting for some reason. Try the link below and just navigating to the Slab topic and the Slabs - Design Strips sub-topic.

http://www.risa.com/risahelp/risafoundation/Default.htm

 

[mhdhamood]

THAN YOU DEAR VERY VERY VERY MUCH IT WAS VERY USEFULL