Also, to avoid torque on the one beam, it would be best to use a long piece of unistrut and extend it in the opposite direction of the 'over-hang', and attach it, so it would be attached to two beams.
> On Apr 4, 2014, at 7:31 PM, Brad Casterline <[email protected]> wrote: > > Required Section Modulus for cantilevered will be the force (pounds) times > the distance (inches), divided by the stress (15,000). The force is the > weight of the water-filled pipe plus 250. The distance is 4" in this case. > Not hanging at 15' just means the force will be less, i.e, if you have these > unistrut at 7'-6", the weight will be half that if they were 15'-0, but you > still have to add 250 lbs to get the force. Please post your results so we > can all look at them, and be prepared to be criticized for not hiring a > structural engineer. The 4x thing you mentioned will also be cleared up > because with regular trapeze it is half the force times half the distance. > Brad Casterline > >> On Apr 4, 2014, at 6:56 PM, "Jerry Van Kolken" <[email protected]> wrote: >> >> I have a retrofit project where I structure will not allow us to install >> beam clamps. The existing hangers are unistrut clamp to the beams and >> extended 4" out to allow rod a ring to be attached. I would like to use a >> similar assembly but I don't know how to calculate the loading to determine >> the size of the unistrut. I've heard some stuff about 4x the section modulus >> based on the trapezes table in NFPA. >> >> >> >> I was also wondering if there is a adjust the section modulus if you are not >> planning on hanging at 15'-0"? >> >> >> >> >> >> Jerry Van Kolken >> >> Millennium Fire Protection Corp. >> >> 101 Copperwood Way, Suite H >> >> Oceanside, CA 92058 >> >> (760) 722-2722 FX 722-2730 >> >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
