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Message No. 11117, Started by nickzen2u on 05/01/03
 Fire truck, truss dynamics question I am a fireman in the city of Chicago and work on a Truck Co. The Truck has a telescoping ladder of parallel trusses joined by the rungs. I have received conflicting advice as to how best to position the tip. One school of thought has the tip softly resting on the roof, and thereby reduceing the load. The other has the tip a few inches above the roof, so as to not unbalence the forces in opposition in the trusses. Which is more important, the structure (a truss) or the manner of support (a cantilever convertd to mixed support by resting the tip) ? This is not a purely academic question, the tip is load rated for 250 lbs, which is what I weigh with all my gear. The rescue of a 200 person seems problematic!
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Follow-up Messages (14)
 Thank you Neil Moran and acroduster, sorry for the tardy post, busy getting... No. 11156, Posted by nickzen2u on 05/08/03, 09:07 PST. I should point out that 250# was the normal load for older ladders, and cur... No. 11151, Posted by tomhays@comcast.net on 05/07/03, 11:39 PST. only 250 lbs? and I thought you firefighters were just a bunch of dumm d... No. 11150, Posted by gerdb on 05/06/03, 21:28 PST. Being a Firefighter myself, and a Driver/operator, I have found in my "ques... No. 11149, Posted by tomhays@comcast.net on 05/06/03, 17:57 PST. I agree wholeheartedly on all points. Thanks for the prompt response. No. 11147, Posted by acroduster1 on 05/06/03, 04:03 PST. Your quite right acroduster, I take on board your comments. But please bear... No. 11145, Posted by neil moran on 05/05/03, 12:32 PST. A few comments on this thread: 1. It seems odd that the rating on the t... No. 11140, Posted by acroduster on 05/05/03, 05:39 PST. I find all of this very interesting even solid beams on a crane may experi... No. 11133, Posted by gerdb on 05/03/03, 19:23 PST. Hello nickzen2u There is more than one aspect to consider here - 1) L... No. 11130, Posted by neil moran on 05/02/03, 12:43 PST. Whew! For a moment there I thought I wasn't going to get my USDA recommend... No. 11129, Posted by rolschwarz on 05/02/03, 12:25 PST. Thank you, Rolschwarz The love of life and dedication of my profession de... No. 11127, Posted by nickzen2u on 05/02/03, 07:36 PST. I would think that one wouldn't want to put additional stress on a building... No. 11126, Posted by rolschwarz on 05/02/03, 05:45 PST. Thank you, Rorschach I am of the same opinion based on the beam mechanics... No. 11124, Posted by nickzen2u on 05/01/03, 21:41 PST. it would seem to me that lightly resting on the structure would be the best... No. 11122, Posted by rorschach on 05/01/03, 19:39 PST.