The IBC code is clear as long as there is a structural ridge beam with posts no thrust will occur at the exterior walls. Therefore no heel connection design is required. Is this because of plate action of the plywood. Any tips will be greatly appreciated. When I place the snow load perpendicular along the slope of the rafter and not along the horizontal thrust forces occur. This is easily verified with Ram Advanse.
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Structural Ridge Rafter Thrust 8
- Thread starter cap4000
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Understood. But there is a 30kn Fx reaction in this link from wind perpendicular to the beam. This is verified with Ram Advanse with a pin and roller support condition. Snow or wind lets say it the same magnitude.
If we are talking about applying wind to the inclined member then yes I agree there will be a horizontal reaction (sorry if this is what you were talking about the whole time). Because in the example shown in the link the wind only acts perpendicular to the inclined member and there is no axial component.
EIT
EIT
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Sum of Moments = 0
Sum Vertical Forces = 0
Sum of Horizontal Forces = 0
Six of one = 1/2 dozen of another (in terms of quantity, unless dealing with a Baker in which case 6 of one will in fact equal 6.5 of other, but in either case I would suggest the sum of the vertical forces is still zero whether the Baker has eaten the 13th roll or not).
Sum Vertical Forces = 0
Sum of Horizontal Forces = 0
Six of one = 1/2 dozen of another (in terms of quantity, unless dealing with a Baker in which case 6 of one will in fact equal 6.5 of other, but in either case I would suggest the sum of the vertical forces is still zero whether the Baker has eaten the 13th roll or not).
Toad: Can I have a doughnut?
Cap4000: Can I suggest to throw out the Ram analysis on this? Do it by hand. In 5 minutes or less using either method you will have your answer which, if you like, submit all the calcs for verification here. There will be zero thrust from snow and you will have a lateral force component from wind. 2 separate calculations -very simple -very straight forward. That is unless your supports are different from a global x/y cardinal direction or you are doing something with them to make them settle or move etc. but even so that can be dealt with.
______________
MAP
Cap4000: Can I suggest to throw out the Ram analysis on this? Do it by hand. In 5 minutes or less using either method you will have your answer which, if you like, submit all the calcs for verification here. There will be zero thrust from snow and you will have a lateral force component from wind. 2 separate calculations -very simple -very straight forward. That is unless your supports are different from a global x/y cardinal direction or you are doing something with them to make them settle or move etc. but even so that can be dealt with.
______________
MAP
woodman88
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- Oct 23, 2009
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cap4000 - To use the "sloping beam method" per Figure 2.6b (your attachment page 16 of 81) you can not ignore the axial (parallel to the beam) component of the snow. The wind condition not having a axial (parallel to the beam) component gives a horizontal reaction. In the "sloping beam method" the 1242 lb parallel to the beam axial force shown has a vertical and horizontal component. The 2484 lb perpendicular to the beam force also has a vertical and horizontal component. These horizontal components, when added together, equal zero.
And because these horizontal components equal zero we can ignore them and use the horizontal plane method. Which does not break the snow load into parallel and axial components.
BAretired - It has been HOT and HUMID here in the Phoenix area. I apologize for letting it get to me to the point that I left the “working engineering methods” that is the purpose of this forum to wander down the paths (and being less than polite about it) of the theoretically and technical explanations which are not part of this forum.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
And because these horizontal components equal zero we can ignore them and use the horizontal plane method. Which does not break the snow load into parallel and axial components.
BAretired - It has been HOT and HUMID here in the Phoenix area. I apologize for letting it get to me to the point that I left the “working engineering methods” that is the purpose of this forum to wander down the paths (and being less than polite about it) of the theoretically and technical explanations which are not part of this forum.
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
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