OT JT joists

[JRGse]

We are currently reviewing the load capacity of existing mezzanine steel joists. We have the existing building drawings that indicate the building was built in 1955 and the mezz joists are #145 OT JT spaced 24"o/c. Field measurements indicate that the joists have 1.25"x1.25"x.1875" angles for the top chord and 0.5" bars for the bottom chord.

I have never see this type of designation for steel bar joists. Does anyone have information on these joists? Review of the 60 year SJI manual does not show any joists series with this designation.

Thanks for the help.

 

[jike]

Most likely, the #145 stands for a 14" steel joist. The OT probably is a typo and should be OW (open web).

It probably is the same as a SJ145 or SJ145W as listed in the old SJI manual.

 

[JAE]

If you get the SJI historical catalogue, they have the 145 joist listed for that time period. The OT JT probably is the engineer's abbreviation for Open Truss Joist.

Do a Google search for Steel Joist Institute and you can order the catalogue there. It is an essential tool if you do many projects with older joists.