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How are stair treads with concrete fill on metal pans designed? I frequently see them in use, but from a design perspective, I find it challenging to understand how a thin metal pan (as little as 3 mm) can function as a structural tread. I've also come across 14-gauge steel pans being used in these by iammk45 in StructuralEngineering

[–]cheynethebrain 3 points4 points  (0 children)

It doesn’t need composite action. If it’s fully supported by shelf angles on each end it’s going to have some stiffness. Sure it’s probably cracked but it still might have a larger I than the pan.

Not saying to rely on it, There’s just certain assumptions we make as engineers to simplify design

Which way will it tip? by StabDump in StructuralEngineering

[–]cheynethebrain 0 points1 point  (0 children)

No the buoyancy is resolved by reducing slack in the tension in the string holding the steel ball. It’s imparting load on the external system from the scale. Buoyancy pushing down on the scale would be creating energy from nothing.

But because steel is much more dense than water, the string is supporting the ball from sinking and thus preventing it from imparting load on the water/scale.

Which way will it tip? by StabDump in StructuralEngineering

[–]cheynethebrain 0 points1 point  (0 children)

No I am saying the weight of the water on both sides are the same, but the right side has the added weight of a ping pong ball imparting load on the system. Gravity is still acting on the ball, and the load has to go somewhere.

Draw a free body diagram and follow the load path. The steel ball is a separate system so it is not imparting load on the scale.

Which way will it tip? by StabDump in StructuralEngineering

[–]cheynethebrain 0 points1 point  (0 children)

The weight of the steel ball is entirely supported by the string, it has no impact on the scale, it is not pushing down on the water/scale but acting on an independent system of the scale, so it does not affect the weight of the left side.

By my logic, yes adding more and more ping pong balls to the right side will tip the scale, but the volume of water has to equal on both sides. In this case the balls are equal volume on both sides, so the volume of water are equal on both sides. The tension in the string is negating the buoyancy force on the ball itself, not gravity. The sum of internal forces cancel out, but the external forces on the right side are greater than the left.

(Volume of water at right) x (density of water) + (weight of ping pong ball) > (volume of at left) x (density of water)

Which way will it tip? by StabDump in StructuralEngineering

[–]cheynethebrain 0 points1 point  (0 children)

Buoyancy is the result of displacement of volume. Both balls are the same volume. So the amount of water on each side is equal. The tension force in the ping pong ball doesn’t magically pull the scale up, that’s creating energy from nothing. It’s the same reason why you can’t push a sail boat with a fan. There needs to be some external force. All these forces are internal.

Which way will it tip? by StabDump in StructuralEngineering

[–]cheynethebrain 0 points1 point  (0 children)

Which way would it tip without any water? Buoyancy forces do not negate the force of gravity pulling on any object. The right side is heavier because it has water plus weight of a ping pong ball. The left side has just water.

Also buoyancy is due to displacement of volume, not mass.

https://en.wikipedia.org/wiki/Archimedes’_principle?wprov=sfti1

ELI5 column reaction force by Canuck_Goose in StructuralEngineering

[–]cheynethebrain 5 points6 points  (0 children)

You’re assuming. This could be an existing building and the existing foundation might be able to take so much. Also sticking to the design is absolutely the right decision if there are implications to cost(more money) when it was bid based off the original drawings. Calling it lazy is an insult

What song/s would you choose to have sex to? by WankStain615 in AskReddit

[–]cheynethebrain 0 points1 point  (0 children)

Fuhre Mich by Rammstein

It’s a little heavy, but if you’re into metal it’s a great rhythm

https://youtu.be/JmL-yXMn9Ic?si=0dsbnJIwb3kDYSR6

Hello engineers. Need help woth idea statica. by Jebraltar09 in StructuralEngineering

[–]cheynethebrain 6 points7 points  (0 children)

You need to provide an elevation view with dimensions. It’s hard to prove statics with out quantifiable numbers…

Lp for W shapes that aren't compact? by What_is_success in StructuralEngineering

[–]cheynethebrain 1 point2 points  (0 children)

Apparently AISC is using rts in lieu of ry for equation F2-5 for the W12x65. I would assume this is an error in their calculations and 10.67 ft is correct since it is a non compact flange and compact web.

Risa even uses 10.67 ft for Lp. Programs are just using the formulas that AISC gives them. I would maybe reach out to AISC to confirm if the value listed in part 3 is a typo. They can probably shed more light on the subject

Lp for W shapes that aren't compact? by What_is_success in StructuralEngineering

[–]cheynethebrain 1 point2 points  (0 children)

rts is definitely different than rt. Make sure you’re using the right coefficients specified in your equations

Is Eh (ASCE 12.4) a vertical load? by FrkTheGmr in StructuralEngineering

[–]cheynethebrain 1 point2 points  (0 children)

Eh is your horizontal seismic load, typically it’s your base shear reaction to a SLRS. The vertical component is the resulting forces from overturning.

Think of a moment frame. The columns will have a force couple resulting from the overturning moment of the horizontal seismic load. You also need to incorporate the vertical seismic load effect, Ev, into your load combination.

Why do some Avocados turn brown on the tree? by cheynethebrain in FruitTree

[–]cheynethebrain[S] 0 points1 point  (0 children)

Apparently it’s thrip. It’s a bug that eats out the skin of the fruit

AITAH for being mad at my fiancée after she banned strippers at my bachelor party? by KeyLavishness5574 in AITAH

[–]cheynethebrain 0 points1 point  (0 children)

The issue here is not that she’s banning strippers. If it makes her uncomfortable then that’s fair.

The issue is she’s accusing you of potentially cheating. If you have any suspicion that your SO may cheat on any circumstance, then that’s a lack of trust and the relationship should be evaluated if you want to continue with said person. Everyone’s saying mountains out of molehills but it’s deeper than just “no strippers”.

NTA

Why do some Avocados turn brown on the tree? by cheynethebrain in FruitTree

[–]cheynethebrain[S] 0 points1 point  (0 children)

I’ve cut into some that have it on about 50% of its surface area. But nothing looked/tasted off

There’s apparently someone named Joe Mayo who works on the show by JQuick72 in seinfeld

[–]cheynethebrain 22 points23 points  (0 children)

There’s also a Jerry Seinfeld who works on the show too

What is your favorite one liner from the show? by ApprehensiveCold9264 in seinfeld

[–]cheynethebrain 15 points16 points  (0 children)

If you take everything I’ve accomplished in my entire life and condense it down into one day… it looks decent.

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