I want to support a roof top tent consisting of a fiberglass shell 57"W x 91"L x 12"H. It weighs 120 lbs. Assume the weight is evenly distributed, although the walls of the shell will be slightly heavier.

Assume a 240-lb adult incl bedding will lie in the center stretched out 74". When the adult sits up, his head- to-torso-to-hip weight line will be approximately 30" from one end of the tent.

The support for this shell will be crossways spanning 57 1/2". IOW, the outer perimeter sides of the shell will rest on the four feet on each side that the cross members attach to. I plan to put cross members at 9" (under the head), 30" (under the hips), 50" (undert the knees), and 79" (under the feet). The cross members will attach to bolts in 2 C-channels running lengthways built in to the bottom of the shell.

I own some 6063 aluminum tubing, 1" square, 1/8" wall, and would like to re-purpose it for this project.

QUESTION: If I bond 2 pieces of the 1" tubing side-by-side using 3M panel bond epoxy, and cut no holes for bolts, will that assembly be strong enough for the 57" span? This will result in a cross member 1"H x 2"W. There will be 4 of them, as I said; but the critical one will be #2 that runs under the sitting-up adult.

Thank you for taking the time to make the calculations.