Bar Joists

By tripdls Date 06-28-2007 17:10

I'm wanting to make my own bar joists, but I don't understand the specs. I'm wanting to build 14K6, 14K3, & 10K1 bar joists. I understand that the first numbers are the depth of the joist, which would be 14" & 10". Does the "K" designate the size of the angle iron and rod used? And I know that the last number is the "chord". What does that mean? Does it have to do with the space between the webbings? I could understand the narrower the space the stronger the joist.

By swnorris (****)

Date 06-28-2007 18:46

K usually designates either a rod web joist or a crimped angle web joist.

Chord means the two back to back angles (with gap in between for either rods or crimped angle diagonals) at the tops and bottoms of a joist.

By tripdls Date 06-28-2007 19:12

Okay, so 14K6 means....? Is it a rod web joist or crimped angle web joist? And as far as the chord goes, the "6" is the size of the rod between the back to back angles?

By swnorris (****)

Date 06-28-2007 20:23

It could mean either one, but typically if the joist is less than 20" deep, a rod web is used. If the joist is 20" or greater, a crimped angle web is used. Whether rod or crimped angles are required is based on the load bearing criteria.

No, 6 is not the rod size. 6 is just a designation for load carrying capacity for a given span. Check out Hancock or Vulcraft websites and look at the load tables. I'm not a joist expert. I just know enough to be dangerous.

By JA

Date 06-30-2007 11:12

Yes , the first numbers are depth size,,,,,,,the "K" is a series of joist that had replaced the "H" series in 1986,,,,,,,,there's a "KCS" series joist that fits the need when constant moment and constant shear (special loading conditions) come into play.....

The last number designates cord size (top and bottom back to back Angles),,,,,,,as Mr. Norris had mentioned , its a simple scale created by the SJI with its own strength values,,,,,2 being stronger than 1 ,,,,, 3 being stronger than 2,,,and so forth....

if i were you , I'd figure out what's needed and duplicate it........

By Bob Garner (***)

Date 07-02-2007 19:44

Check out the Steel Joist Institute (SJI), they essentially write the rules on bar joists (steel joists).

By digger doug Date 07-24-2007 17:25

tripdls,
you may find that all of the lit. is just to size what you want for your load.

I see you know what you want, now to build it....

14k6= 14" high, 1 1/2" x 1 1/2" x 3/16" angles on top, .656 dia. web rod (UPSIZE TO 11/16 OR 3/4)
   BOTTOM CHORD= 2 rods .719 dia. (upsize to 3/4)
   pitch of web (distance between "vees") 18"

14k3= angles, 1 1/4" x 1 1/4" x 1/8", web, .594 (upsize to 5/8) bottom chord, 2 rods .531 (9/16)
web pitch 18"

10k2= angles 1" x 1" x 1/8", web .469 (1/2") BOTTOM CHORD, 2 RODS .469 (1/2")
web pitch 14"

end the bottom rods 1/2 pitch from end, bend up to seat, max. seat 5" long

   tnx
   doug