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Heavy bar grating multiple span loading capacity of bar grating bolted down with clip 1

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mikeDP

Structural
Mar 24, 2020
1
from previous post seems like.

Once20036 (Structural)4 Apr 17 21:11
Why not call the manufacturer?
The ability of decking to handle negative flexure will vary based on the specifics of the deck.
The deck we typically specify has bearing bars in one direct, and small rounds in the other direction. These rounds will brace the compression side of the bearing bars for positive flexure, but not negative flexure. Like the cantilever beam over a column/inflection point bracing question that comes up routinely, if you're using this type of deck you`ll have a huge unbraced length for the compression (bottom) flange, and hence very little capacity.

once20036 is the only one who knows anything.
like so often today you call and no one knows anything. they have no idea what unbraced length is. world is getting scary.


Need help multiple span grating large grating 5"x 1/4" 3'-6" spans three span.
reference, bearing bar and unbraced lengths. heavy loads. and need help anchoring down to steel with a clip.
 
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What manufacturer did you call? Bar grating isn't exactly tough to manufacture - there's bound to be some numbskulls in the business. But then you have your McNichols and Nucor/Fisher & Ludlow types with competent engineering staff responsible for custom in house designs.

How are your loads applied? What kind of load are they? What kind of help do you need anchoring it down?
 
mikeDP said:
...large grating 5"x 1/4" 3'-6" spans three span.
...need help anchoring down to steel with a clip.

Grating that is 5" x 1/4" is covered by ANSI / NAAMM Standard MBG 532-19, "Heavy Duty Metal Bar Grating Manual".

Page 8 covers anchorage requirements, including the following statement:
"All gratings are to be anchored firmly to their supports by positive means."
Only two types are anchorage are covered, "Welded Anchorage" and "Welded Lugs". Welded lugs on grating are anchored to supports using studs or bolts.

My interpretation of the standard is that clips (as used with lighter grating) do not meet the requirement of "positive means".

[idea]
 
IKG is a grating manufacturer that I know employs some PE's. You might try them. Typically a grating of that size, especially if on continuous spans, would require welding or use of fastener plates welded between main bars and then bolted down.
 
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