Intamin proves itself yet again

Then and Now . I remember seeing a site with more details on the Shockwave case, can't seem to find it now.
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Never Has Gravity Been So Uplifting.
*** This post was edited by BullGuy 3/4/2003 9:07:40 PM ***

Getting back to Goliath...

That circular weld bridged by the new gussets is at the low point on the ride. Any deflection of the structure at the top of the column translates into magnified force applied directly to that weld at the base of the column. The gussets will stiffen the column at the weld and keep the weld from cracking. Now instead, the column itself will crack just above the gussets, but the hope is that the material is strong enough to prevent that from happening. :)

--Dave Althoff, Jr.

Looking at those before/after pictures of Shockwave, I'm surprised that they actually built them without the extra bracing. Being as unscientific as I am, the bracing just seems like common sense to me...

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My K'Nex Coasters
Sorry, sig out of order. Technician has been called.

I really hate to argue with Rideman, but Dave, you're not 100% correct. What they're doing is not so much increasing stiffness as decreasing stress concentration.

When you have a beam in bending, with a change in cross section, you get a stress concentration. This is an area where peak stresses are much higher than average bending stress in the beam. (actually any stress, but we're dealing with bending here) If you couple this with the relatively hard and brittle metal in a weld, then the effect is magnified. What the gussets are doing is alleviating some of that stress concentration factor, by increasing the effective "radius" of the joint. Stress concentration factor is proportional to radius. The beam won't break above it because that far from the joint, there is no real stress concentration (stress concentration is often approximated as zero more than three radiuses from a feature)

This is also the reason if you tear apart an engine and look at any of the shafts, the features are filleted together, instead of coming to sharp points.

And a nitpick. The force at the bottom of a column is exactly the same as the force at the top. It's the bending moment that increases with distance.

Argue with me all you want, Comatose, particularly when you're right. Remember, I'm not an engineer. I know that stress cracks form at points of inflection (and for a particularly obvious example, this is why aircraft windows are radiused at the corners) and I know that the welds on those columns are an ideal location for cracks to form, particularly close to the ground where the joint is subject to high torque when the train goes by. And I know that reinforcing the joint with the plate gussets should change the loading on the weld enough to fix the problem.

You, on the other hand, can accurately explain why this is the case. Thanks!!

--Dave Althoff, Jr.

Come to think of it, similar "Fins" were affixed to Superman Ultimate Escape's front tower right above where the track starts to twist, after the first season.

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Jes
Jes's Roller Coasters DJ Jes
Six Flags Worlds Of Adventure Ride-Ops Crew 2002-2003(Have Fun Trying To Find Me!)
*** This post was edited by Zero-G 3/5/2003 6:48:25 PM ***

Actually stress and strain are pretty directly linked, so the addition of the gussets is reducing both. (strain relates to stiffness)