Ive seen the local farm machinery manufacturer slide from their No.1 position in silage trailers. They used to build a very robust silage trailer in the 80s and 90s by using the next size up in C channel that their competitor used. But they stuck with the mindset of using big beams. An apprentice was once told to stop beveling square tubing for weld penetration, farmers want to see heavy welds in sight, and when its full penetration, farmers dont see that...
In the short term, bigger is better, but when products and manufacturers get time tested, proper engineering wins over sheer dimensions.
Made me wince. I cut my teeth at a drafting table working for Chicago Bridge & Iron. Every weld got bevels. CBI standards only permitted the most rudimentary weld symbols, all welds got a cross section drawing explicitly showing the bevels, depth, flat in the center, and a sacrificial pass in the center before the final pass outside and inside. Then again a 1" plate was thin for what we were doing.
About this time a platform collapsed in a hotel, in Missouri I believe. Revelers were dancing on a platform about the 3rd story that had another platform hanging from it on the 1st or 2nd above street level.
There were many construction goofs vs the architect's drawings. Square "tube" was made by welding two channels together. Simple surface weld, no beveling, certainly not full penetration. This failed, but might not have. The problem was something like a 40' rod was to be used, with a threaded section in the middle, the nut on these threads to hold the middle platform. A rod like that is crazy to procure, maybe get one threaded full length but 40'?
So without engineering approval the contractor purchased (2) 21' rods (for each of about 6 locations), threaded each end. Then put 2 holes through the now-square channel, right through the seams. One hole held the support rod from above, the other hole held the platform below. Now the square beam and it's lousy welds was carrying the load of 2 platforms. Nut pulled through, platform collapsed, killing many.
Had the contractor used a turnbuckle to extend the rod rather than use 2 holes in the beam he might have gotten away with it. The seams in the beam from making square out of two channels was also fishy.
