mennometis
Member
This message is a reply to an archived post by Bill VA on March 23, 2015 at 09:28:08.
The original subject was "Hay Wagon Bed Design".
Well it is my turn and I've decided to go the engineered route to size the main beams. The design bending strength formula you need is (WxL)/(8xZ) to determine the material/dimensions.
W is the load you want to carry
L is the span in inches
Z is the section modulus of the lumber cross section
For example, I am going to use spruce 2x8's which have a section modulus of 13.1 cubic inches. I want to match the capacity of my 3-ton chassis using a 10 ft (120 inch) span. This gives me a design bending strength of 6870 psi.
2x8 #2 spruce has a bending strength of 1050 psi (neglecting adjustment factors) so I'm going to need a total of at least 6 boards.
Reworking the formula for 6 boards (3 per beam) gives me a final capacity of 5502 lb between the front and rear axles.
Then I'm just going to run decking perpendicular to the beams and skirt around with 2x4 to keep them even.
The original subject was "Hay Wagon Bed Design".
Well it is my turn and I've decided to go the engineered route to size the main beams. The design bending strength formula you need is (WxL)/(8xZ) to determine the material/dimensions.
W is the load you want to carry
L is the span in inches
Z is the section modulus of the lumber cross section
For example, I am going to use spruce 2x8's which have a section modulus of 13.1 cubic inches. I want to match the capacity of my 3-ton chassis using a 10 ft (120 inch) span. This gives me a design bending strength of 6870 psi.
2x8 #2 spruce has a bending strength of 1050 psi (neglecting adjustment factors) so I'm going to need a total of at least 6 boards.
Reworking the formula for 6 boards (3 per beam) gives me a final capacity of 5502 lb between the front and rear axles.
Then I'm just going to run decking perpendicular to the beams and skirt around with 2x4 to keep them even.