Straight application of loads needs to take into account any deterioration on these old structures. That is why reliance on Load Rating is key. It is the same process DOT's rely on to allow overload permits, etc.
Yes, paying attention to stability as deck is removed is key. Make sure those...
All good points. We have an outside 2nd check engineer on board; wanting to avoid errors.
Can anyone address the question of correct use of Rating Factor? This is my main question:
Is the following the correct way to compare moments using the Rating Factor?
H-15 Moment x 1.32 Rating Factor...
Some pics.
I'm looking for some pretty narrow feedback on correct use of load rating factor. I recognize we don't know each other, so there is no context for this request for help.
Yes understood on operating restrictions and track pressures. I typically take 100% of excavator over...
Only the overhangs will be demolished with excavator up top. Everything else is sawcut crane show from grade.
The load rating was performed 2016. It is a fracture critical structure still in use by public at this point, so it has been inspected every 2 years for a while.
Shutting down the trains, covering the tracks, and wrecking conventional letting it all fall would be easiest / safest. However, RR closures come at significant cost.
At the end of the day, an excavator is going to walk on this bridge. Any help in confirming correct use of Rating Factor would...
Excavator will be used to hoist sawcut pieces off deck off the stringers. It's behaving like a crane.
The excavator will only be operating on portions of the bridge that are intact, so a load rating comparison still valid.
Anecdotes are fun, but I'm left curious about the analysis. Always like videos of collapse, thanks.
We are wrecking over BNSF rail yard. They don't like things falling into R.O.W. !
I am attempting to compare excavator loading on a bridge with rated loads. My typical approach is to compare load effects of design load with proposed equipment. In this case, contractor is trying to maximize equipment size and I'm looking to bridge rating to sharpen my pencil. The bridge is...
I'm performing some load comparisons on an older Steel Tub bridge in order to attempt to justify the use of an outrigger crane for purposes of some retrofit work.
I'm comparing outrigger loads from a crane with HS-20 loading. The idea is to place the outriggers over the stems to avoid loading...
Lomarandil: Yes, the punching does imply moment. Good point.
I found another equation posted over here:
http://www.eng-tips.com/viewthread.cfm?qid=418241
This looks like more what I'd expect...presented in terms of moment, not shear.
JoshPlum: Do you have a reference on where you pulled this forthcoming HSS wall moment equation? Did it come from the Abolitz and Warner paper "Bending for Seated Connections"? I found a link to purchase this paper here: https://www.aisc.org/.WJJEMPKCokV
Thanks in advance.
Thanks Lomarandil and jayrod12.
Yes, I was looking at 13th ed., so we are talking about K1-3 in the 14th Ed.
Assuming a theoretical weak padeye approach makes sense to avoid punching shear. However, if you take an extreme example and assuming Rn is acting 10-ft away from the face of the HSS...
SAIL3: I attached a photo to the original post with some redlines showing the proposed padeye and direction of loading.
I agree K1-10 provision isn't adequate to address this load case.
thread507-410454
My first post here...I've encountered a conflict in the field (I'm a contractor's engineer) where they are needing to weld a padeye to an HSS.
The HSS is part of a larger panel that will be tripped from horizontal to vertical (thus the padeye will experience loading...
