Tony Montana

Which one is stronger,going to last longer and is one more expensive then the other(material itself)?

Chris Sunkin

The answer is... that depends. Pound for pound in equivalent material, I-beam is stronger. Can't say as I've ever seen an I-beam steel trailer though.

crb76

C-channels are the bomb. The dont flex and ride much smoother than I beam. The weld helps. Go with 8inch cross members on C-channel versus 6 and it is that much stronger.

Tony Montana

Talking about aluminum

CigDaze

Chris said it: It depends.

Given an I-Beam and a C-beam having equivalent overall dimensions and wall thicknesses (same cross-sectional areas), they will be equally "strong" in tension, compression, shear and even short-beam bending when the bending is applied relative to each respective horizontal neutral plane when looking at them as a "C" and an "I" - this is due to the two beams possessing identical moments of inertia. The I-Beam will be more stable though, and will be superior in long-beam bending when flange crippling and column buckling overtake pure "strength" as the failure mode.

However, when bending them transversely to the above stated case, bending along a horizontal plane when looking at the beams as a "U" and an "H", the "U" will be much stronger as it will have a larger moment of inertia.

Also, a "C" or a "U" will be stronger in torsion than will an "I" or an "H"