phamENG - I usually appreciate your contributions, but a slight disagreement here.
You say: "I would say LRFD is inappropriate for machine design." Untrue.
Machine design has many limit states and many loading conditions.
Hard to imagine LRFD as not an appropriate framework, unless it is...
Cement dust is deadly.
Fly ash is deadly.
Slag cement is deadly.
When bound together, not deadly.
I've had to explain this many times to city environmental compliance officers, who have blocked the use of standard concrete mixes for deep foundations (since they assume the carcinogens will leach...
Thanks all for the responses.
DekDee said "...Regardless, if it is 1", 3" or 8" - it must comply with the WPS regarding preheat."
I think this is a common disconnect, and vague in D1.1. For structural steel, shop preheat (for shop conditions above 50 deg) before tack welding is not the...
Thanks for the replies.
However, this feels a little like my college Philosophy class. Plus whack-a-mole.
I have no idea what is in the mind of the fabricator. And my general feelings (negative) and past experience don't matter either; what matters right now is code and contract language. And...
Shop temperature range: 40 degrees to 60 degrees (technically below the 50 deg min in the mornings)
Customarily, no pre-heat is used with tack welding for structural steel, and none used for this project. Preheat used for production welds as required.
Code is AWS D1.1-20
Material: A572
Thickness: 0.5" stiffener plate to 1.5" thick flange (1.5" flange is high load tension component)
Application: statically loaded built up plate girder (similar to bridge, but not D1.5)
Shop temperature range: 40 degrees to 60 degrees
Dual shield w/ C25...
Yes, agree with you all.
No contention about ownership or legal rights.
My heartburn is in the obvious - said ownership of documents and AISC certifications have little correlation with fabrication quality. Zero link with personnel or staff credentials. It's all just paper.
That's all - thanks...
Thanks for the responses.
What I was trying to communicate is that the new Shop B is actually the brain trust that developed everything for Shop A, and Shop A now has nothing but the paper (no talent). Shop A owner claims, "Yep, I've been doing this for 30 years" but lost all the intellectual...
Here is my understanding of D1.1-2020, Clause 5 and 6.2
Steel Fab Shop A has a single owner and 20 employees
All the employees leave to start Fab Shop B.
Fab Shop B cannot bring with them any of the WPS or PQR documents, but instead must start from scratch - PQR and WPS.
Fab Shop A hires a new...
Hey guys, that was just my attempt at satire. I would never even think of tackling something so far outside my expertise - especially when rotating machinery is involved.
Not to change the subject, but...
I am on a project in a electrical yard, and all of our electrical engineers are busy, so even though I'm a structural engineer, I am going to try my hand at cross discipline work.
I know next to nothing about electrical or power engineering.
The task at hand is...
"...our power grid is not critical infrastructure"
Maybe not for John J Rambo or Jeremiah Johnson, but your definition of critical is a bit narrow. If reliable commercial power isn't critical for urban and suburban areas of a developed nation, not sure what is.
Hospitals, fire stations, pumping...
I bet we all agree on this:
Critical infrastructure - including substations - should be resilient, so these facilities can withstand vandals and semi-organized bad actors and hurricanes and floods and earthquakes and years of neglect and non-maintenance. That's the only engineering I see in...
Reading the news article from the links above, it appears city folks don't quite understand their fellow rural citizens.
It could be domestic terrorism. Seems unlikely, and hopefully not.
More likely - a young wayward male with a hunting rifle, and too much time on his hands and no concept of...
Here's a question for the D1.6 stainless welding code experts.
Joe Welder’s FCAW-G (using A5.22 filler) performance qualification shows:
- Base material = 304L [base metal group A]
- Filler = 308LT1-4 [filler metal group B with C25 gas]
If I understand Table 5.3, Table 6.5, and Table 6.11, then...
In the US,
for structural steel work (not pressure vessel, not aerospace),
for low carbon and HSLA,
for plate thicknesses 1.5 inches (38mm) and less,
PWHT almost never required.
CMCs have their place, but tend to be oversold.
Some CMCs have reinforcing, but the typical CMC is not reinforced. They have no ductility and no lateral load capacity. You know how a C39 concrete test cylinder normally breaks in the lab - classic 45 degree tension crack? CMC exhibit the same...
Using non-shrink ground as a replacement for concrete is rarely a good idea. Grout requires confinement, and most grout manufs do not recommend placement that results in large open, unconfined surface areas. Do not confuse grout with concrete or mortar. Nonshrink grout (ASTM C1107) includes...
I mostly agree with EireChch, except for the very last part.
For the AASHTO method (most common, but different from the many other standards), the soil over the heel of a cantilever wall also has a pseudo-static lateral component. See 11.6.5.1 (8th Ed, 2017).
Not defending or promoting this...
Agree with PEInc.
Geofoam is your friend. You may need a multi-pronged approach. Don't simply think of adding strength. Reduce load.
Increase strength and reduce load and ensure slope stability.
With my 38 second perspective, I'd say slope stability and long term creep is the top of the list...
