huangyhg

design literature on hip roofs
can someone point me to where i can find design techniques for wood framed hip roofs? i refer to hip roofs that have no ceiling joists or cross ties, providing a cathedral type of look.
i'm sure the hips will produce a thrust at the lower support corners. but i'm unsure to what happens to the reactions from the hip at the top of the ridge.
also if there's a continuous ridge, can the rafters at either side be designed as a 3 hinged arch? of course, this will also exert thrusts on the tie beam below.
any suggestions on finding calculated examples will be welcomed.
find a job or post a job opening
on my previous job i specified bent steel beam (not really bent, just welded in an angle).
never, but never question engineer's judgement
this project is an old residence (1956) with a hand framed hip roof. problem is the new owner wanted a cathedral look and during remodeling the contractor saw no problem in removing all the ceiling joists (that basically act as tension ties)and gave the owner what he wanted. i had done the structural engineering for a 2-story addition. of course, during a site visit i saw what had been done and almost had a cow.but the contractor (not an engineer) keeps reassuring the owner that i'm exaggerating and is not a big deal...any thoughts?
i think the contractor and owner are both morons, and they may well come to that realisation in the next big wind storm or snow storm.
the thrust has to be resolved by some means. just follow the load path.
dgpe....if the walls can't handle the thrust, you will have to have collar ties/beams. if i can dig one up, i have photos of a similar failure...this one due to excess collar tie spacing and no ceiling joists.
before jump into conclusion, i suggest to look into this matter from another angle. if you are asked by the client to come up a solution to make the existing roof the cathedral type, what would you do? i think you will be glad to take on this challenge rather than an outright answer "no".
once you have came up your own solution, then you can back check, and point out the problems with the non-engineered works with confidence. two specific areas i would look into - the roof geometry and
i have a pretty good idea of how to design it (if from scratch). but on an existing roof, how can you handle the reaction from the hip rafter at the top of the ridge without ripping whats remaining of the roof to take care of this load? other than that, it's a matter of detailing the proper connections between
i'm not sure how the removal of the ceiling joists has affected the hip to ridge connection. wouldn't that connection have always been subject to thrust from the hip?
"it's a matter of detailing the proper connections between members and using the proper connector to transfer the thrust ..."
i think that's the key. in a beam-column (rigid bent), as long as the joint is capable of handling the moment carried over by the
the concept works well for a simple rectangular hip structure, but can get real complicated real fast when the rectangularity is lost, as is with most architectural designs.
mike mccann
mmc engineering
if there is a really bad problem, you will be able to see it almost immediately in the walls. put a level on the walls to see if they are still plumb. i have seen this many times when people try to add a loft even on a gable roof.
a gable roof can be a little more forgiving because the ridge can act [somewhat] as a beam. but with a hip roof, you should be able to see movement at the top of the walls pretty quickly - especially near the center of the wide portion of the house.
i agree with hokie that both the contractor and the owner are morons if they don't think there is a huge potential for a problem.

__________________
借用达朗贝尔的名言：前进吧，你会得到信心!
[url="http://www.dimcax.com"]几何尺寸与公差标准[/url]