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Old 07-03-2013, 01:43 PM   #11
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Yet!
Was the welder also a structural engineer?
One does not have to be a structural engineer to fabricate and build a hitch or know what the frame will take. Experience is a wonderful teacher. Have seen plenty of "degreed engineers" that were great with the paper and dumber than a fence post with practical application. Just what I've observed over the years. Kansas City sky walk was a prime example.

Bottom line, it is foolish to add a bike rack to the rear of a "lite wt" camper bumper. You are asking for big trouble.
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Old 07-03-2013, 02:14 PM   #12
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I'm not saying you don't need to be careful.

But I've actually READ the report on the KC skywalk. Fault wasn't with the "degreed engineers" who designed it. They specified single (20 ft, as I recall) threaded rods to hang the skywalks. The CONTRACTOR (not a professional engineer, just "experienced," but apprently not experienced enough) decided to use two 10ft rods instead and jury-rigged a connection between them. (I don't recall if they were overbudget and thought two 10 footers was cheaper, or if they couldn't get the 20 footers when they needed them; it was one of those two reasons.) Anyway, it was the connection between the two rods that failed. The original 20 ft rods were plenty strong enough as designed by the engineers.
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Old 07-03-2013, 02:23 PM   #13
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Then try the Tacoma Narrows Bridge! I'm sure there was a design fault there!
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Old 07-03-2013, 02:26 PM   #14
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I would go to a hitch shop and talk to a professional. I'm sure people here may be passionate but a hitch shop will easily come up with a safe solution for you.
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Old 07-03-2013, 02:43 PM   #15
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Ok, you guys sold me. I'm leaving them in the rear bike door for which it was intended! Rockwood 8286ws
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Old 07-03-2013, 02:52 PM   #16
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...The original 20 ft rods were plenty strong enough as designed by the engineers.
There were still engineers over looking the construction that should have caught it. Changes are not made without engr. approval.

Matters not with the discussion at hand. Sorry to have brought it up.
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Old 07-03-2013, 03:25 PM   #17
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Changes are not made without engr. approval.
Not necessarily true. In this case, the design engineers were NOT consulted. You can't trust a contractor any more than you can trust anyone else.

We're all trusting that our hitch designers are doing it right. But you never know. And you never know if the welder putting it together didn't get distracted and end up with a void in his weld, that cracks just as you go over that rough railroad track. Your also trusting that the bike rack is adequate. Same design and construction issues apply.

"You pays your money and you takes your chances!"
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Old 07-03-2013, 03:38 PM   #18
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Correction: Couldn't find the report, but here's what Wikipedia had to say:

Investigators concluded that the basic problem was a lack of proper communication between Jack D. Gillum and Associates [designers] and Havens Steel [contractor]. In particular, the drawings prepared by Jack D. Gillum and Associates were only preliminary sketches but were interpreted by Havens as finalized drawings. Jack D. Gillum and Associates failed to review the initial design thoroughly, and accepted Havens' proposed plan without performing basic calculations that would have revealed its serious intrinsic flaws — in particular, the doubling of the load on the fourth-floor beams.

You can see a pic of what the bad design looked like and how it failed. Bottom line: you're always the mercy of anyone who's been involved, engineer or "experienced" person.

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Old 07-03-2013, 03:38 PM   #19
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Not necessarily true. In this case, the design engineers were NOT consulted...
Design engr's might not have been consulted but there had to be an "engineer" on site during the construction and I find it hard to believe a construction foreman made the decision without consulting the "on site engineer". The foreman may not be the sharpest tack in the pack, but they are not stupid. Did the design engineers not inspect the project when finished? tsk, tsk.
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Old 07-03-2013, 04:10 PM   #20
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anybody can add anything to Wikipedia
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