Was wondering what other Engineer's are using for supported floor (2nd floor, 3rd floor, etc.) live loads for the 21st century classroom concept in current school design. With older schools it was 40 psf classroom, 80 psf corridor's, 100 psf for stairs. Those areas were fairly well delineated...
Just some additional information that did not seem pertinent at the time I replied the first time - Vulcraft also provided the min. panel size for the particular truss depth
joist depth/ panel size
10"/1'-7" 12"/1'-7" 14"/1'-7" 16"/2'-0" 18" Rod/2'-0" 18" Crimp/4'-0" 20"...
About 10 years ago I asked Vulcraft basically the same questions and got the following:
Joist depth/Minimum Base Length
10"/5'-2" 12"/5'-6" 14"/5'-10" 16"/7'-0" 18" rod/7'-4" 18" crimp/9'-4"
20" rod/7'-8" 20" crimp/9'-10" 22"/10'-6" 24"/11'-0" 26"/11'-0"...
I was told this once but never tried it - If the CMU is exposed on the outside and you have access to a hose, spray water on it. The grouted cells will turn darker than the ungrouted.
The best that I can tell, prior to 1946 - A9 is the only steel indicated w/ an allowable tensile stress of 18 ksi.
Starting with the 1946 (until 1949) spec, it changed to A7 (the allowable stress stayed at 18 ksi) and says "except that joists or parts of joists formed of strip or sheet steel...
Don't know if it is available on line - but here is the info FYI
Design chart used was dated 1929, updated to 1948 (the chart updated to 1952 is the same except the 14' span goes up to 179 plf and the 15' span goes to 156 plf)
SJ82
8" deep Mr = 52,500"# Allowable End Reaction 1,900#...
CAN you do it? I would have to say yes - with the concerns and detailing that JAE has described.
However - If there is a requirement or concern about wind uplift or diaphragm shear capacity, I would think that attachment from the bottom would not offer the same capacities as attachment from...
My guess is that it would depend upon the contract, the pre-caster and the capabilities of that pre-caster. I worked as a design engineer for a precast manufacturer in Ft. Worth for about 2 years. We did mostly prestressed/precast parking garages but site requirements sometimes forced us to...
As relates to embedding the columns into the footing: In Chapter 5, Section 5.12 (P.5-18)in the 2nd edition (red book) of the PCI Handbook for Precast and Prestressed Concrete(its been a while since I left the industry) there are 2 design examples for structural steel haunches - steel "W" and...
The only system that I was aware of (and there are probably others) was the Butler Delta System.
Check out Thread507-273628 in this forum where it is discussed.
Good Luck!!
If you can get hold of a copy of "Steel Structures, Design and Behavior" by Salmon and Johnson. Chapter 8 will pretty much tell you more than you want to know. My copy is copyrighted 1971 so newer editions might be formated slightly different.
I have a Design Handbook (Light Gage Structural Steel Framing System Design Handbook) published by the Light Gage Structural Institute dated about 1991. In it, they give design values for various light gage sections considering three different beam span conditions (2 span, 4 span and 6 span)...
Have used 11-7/8" LVL's @ 12"o.c. up to about 25' before - spacing and/or final depth would depend upon lateral and gravity loads. I wouldn't think the actual analysis and design methods would be different from a 2x6 or 2x4 wall as long as you complied with bending, lateral deflection...
