Calculation of symmetrical duopitch ridge beam

[Wiseel]

Hi all,

I'd like to ask if anyone could offer any advice as to how to approach bending calculations for a prefabricated duopitch roof ridge beam; basically a ^ shaped beam, supported at either end. I assume that maximum bending would occur at the ridge point, not exactly sure how to get there... Any help would be much appreciated.

Thanks

Wiseel

 

[hardbutmild]

Could you provide more information? What is the material - concrete, timber or steel? Is the bottom part of the beam straight or is it the constant height element placed at an angle?

 

[BAretired]

It would be very unusual to have a ^ shaped ridge beam. Normally, the ridge beam is horizontal with the roof sloping down on each side. Please clarify.

If we are to believe your post, bending moment of a ^ shaped beam under gravity load would be identical to a straight beam, assuming the supports are pin and roller. If both supports are pinned, the beam will be an arch with reduced bending but additional compression.

 

[SWComposites]

by "bending calculations" do you mean stiffness or strength?
and by "maximum bending" do you mean the maximum stress in the cross section? if yes, then you just need to find the neutral axis and moment of inertia about that axis, then axial stress = Mc/I.

 

[phamENG]

It's just a beam. wl^2/8 where l is the distance between supports.

Pay attention to stability, especially at the peak.

There's a fine homebuilding article in it showcasing a design design by one of our members.

 

[hardbutmild]

It's just a beam

If the height of the beam is constant. If however bottom of the beam is straight, specific checks must be made.