I am working on designing a post and beam style, three bay barn and I have confused myself about the horizontal thrust due to the lower bay rafters. I have attached an image of what area I am confused about. I understand the concept of thrust due to two opposing rafters that meet at a roof peak and also understand the effects of a ridge beam.
If the thrust is effectively handled by by the horiz. tie beam is there still thrust that acts on the upper "beam" where the rafter meets it? Also, if there are only horiz. ties every 18feet will the "top plate" of the outer wall see the bending stress due to the thrust from the rafters that are in between the tie locations? Or will the ties completely handle the effects of thrust for the entire roof/wall section?
(https://i878.photobucket.com/albums/ab345/tomostrow/Rafter.jpg)
The horizontal ties are confusing you. Whiteout them for the moment, what have you got? Posts holding up a "structural ridge". The rafter is just hanging from a higher beam and resting on a lower one. There is no thrust here :)
Haha...boy I feel dumb now :). Thanks for setting me straight! I guess if you look at something for too long you can convince yourself of anything!
Isnt that the truth! Often when Im confused about something its something simple that I make difficult. KISS theory is often overlooked!