03-04-2015, 09:14 PM
Okay, just to provide anyone reading this thread who maybe making a future model or real structure I will provide the following theory for you to understand what is going on and why.
If you look at Steve's drawing, good drawing btw, you will notice that the green braces point upwards to support the upper corners of the doors, this is because gravity is trying to drag down the weight of the door at these points and timber is much stronger in compression [pushing] than it is in tension [pulling], so the diagonal brace transfers the weight to the hinge side of the door frame and the hinges transfer the weight of the door to the structure.
Also by placing the braces diagonally you end up creating triangular shapes which are very strong and help to resist the "racking" created by gravity and other forces. If you look back at the photos of the roof trusses you will notice that they create a series of triangular shapes within the truss triangle and they are designed to strengthen the truss and share the loadings.
You could place the braces in tension as you do with a wire brace, but then you are trying to work against gravity and it is trying to constantly open up the joints. By having the brace in compression [pushing] gravity is working to keep the joint closed, so less stress on the joint.
You will also find that hinges at the top and middle of a door frame will spread due to the weight of a heavy door and this will cause the tops of doors to rub against the door jamb if single or each other in the case of a pair like shown. The easiest fix [if possible] is to swap top and bottom hinges instead of planning doors or checking hinges, failing that swap the hinges for new ones. Many tradies/carpenters dont realise that this is the solution as they only look at the rub point not the true cause. Logical cause and effect analysis is not a strong suit with many tradies and other people.
What BR60103 is also correct as people make mistakes and/or improvised solutions. I have seen panel doors hung upside down with the long panel down because someone thought they "looked better that way", even though the fat kick rail was now at the head. It happens, go figure.
I hope this helps with your modelling or even with real doors at home.
Mark
If you look at Steve's drawing, good drawing btw, you will notice that the green braces point upwards to support the upper corners of the doors, this is because gravity is trying to drag down the weight of the door at these points and timber is much stronger in compression [pushing] than it is in tension [pulling], so the diagonal brace transfers the weight to the hinge side of the door frame and the hinges transfer the weight of the door to the structure.
Also by placing the braces diagonally you end up creating triangular shapes which are very strong and help to resist the "racking" created by gravity and other forces. If you look back at the photos of the roof trusses you will notice that they create a series of triangular shapes within the truss triangle and they are designed to strengthen the truss and share the loadings.
You could place the braces in tension as you do with a wire brace, but then you are trying to work against gravity and it is trying to constantly open up the joints. By having the brace in compression [pushing] gravity is working to keep the joint closed, so less stress on the joint.
You will also find that hinges at the top and middle of a door frame will spread due to the weight of a heavy door and this will cause the tops of doors to rub against the door jamb if single or each other in the case of a pair like shown. The easiest fix [if possible] is to swap top and bottom hinges instead of planning doors or checking hinges, failing that swap the hinges for new ones. Many tradies/carpenters dont realise that this is the solution as they only look at the rub point not the true cause. Logical cause and effect analysis is not a strong suit with many tradies and other people.
What BR60103 is also correct as people make mistakes and/or improvised solutions. I have seen panel doors hung upside down with the long panel down because someone thought they "looked better that way", even though the fat kick rail was now at the head. It happens, go figure.
I hope this helps with your modelling or even with real doors at home.
Mark
Fake It till you Make It, then Fake It some More