u/tajwriggly

I have a situation where a horizontal cold joint was created in a reinforced concrete beam, about 300 mm down into an 800 mm deep beam.

I am of the opinion that this joint severely compromises the capacity of the beam. Specifically, I have shown through interface shear calculations that the ability of the beam to resist transverse shear across this joint is somewhere between 33%-60% of the original monolithically designed section.

A typical shear flow calculation (VQ/It) would show just how much transverse shear this plane should be resisting - highest near the ends of the span where direct shear is highest. However - when I apply the cracked moment of inertia of the transformed section into a shear flow calculation - I get outrageously high stresses - stresses that are orders of magnitude higher than even a monolithically cast section would be able to resist. It makes sense when I compare the same calculation to the gross moment of inertia though - my cracked moment of inertia is lower by similar orders of magnitude.

I am of the opinion that the beam was not poured in conformance with the drawings and specifications and should be demolished and replaced. The contractor is of the opinion that everything is perfectly fine because it's just concrete. My project manager is of the opinion that I should do some calculations that show it either absolutely doesn't work, or that it does in fact still work and we can accept it as-is.

I thought I was on the right path with checking shear flow, and comparing that to the interface shear transfer resistance that can be developed across the joint, however it is clear to me from the math that once the section cracks (not the cold joint - just cracking from bending) that shear flow calculation doesn't seem to be valid for this scenario as it is no longer a homogenous unit.

Does anyone have any ideas on how to analyze the new capacity of this beam? I am considering just analyzing the bottom portion of the beam, below the cold joint, as the "beam" and ignoring the portion above. The stirrups should be fully developed into the top portion still so there shouldn't be an issue with ensuring they are developed. This would be a pretty simple way of checking the bending capacity at mid-span, but it doesn't seem feasible at the supports (designed as continuous span over columns), as then I'd have a "really thin beam" over the columns - but again maybe that is the way I show that it certainly doesn't work?

Today, I have witnessed three 2s on the flop twice. Not in a row, not even at the same table, but twice in one day.

The odds of seeing any given three of a kind on the flop is just over 200 to 1. If you're playing enough hands in the course of a day, you should expect to see this three of a kind on the flop once.

The odds of seeing three of a kind on the flop twice in one day is just over 45k to 1. You would have to play a LOT of poker to see this occur.

The odds against seeing what I saw is 1.2M to 1.

I swear this game already gives out an ungodly amount of straights, flushes, and full houses. What should be 99% odds at winning a hand are overcome on the river with one of those sequences far more often than 1% of the time.

But to flop three 2s twice in one day is egregious. Whoever programmed this game certainly has a vested interest in making people think that the odds at poker are way better than they actually are, and they're going to get people suckered into spending real money on it at some point whether it be in a casino or in another app.

I'm having a bit of a back and forth with a colleague about bar laps at construction joints.

If a lap is required at a construction joint, I prefer to see the lapped bars fully on one side of the joint, I don't want to see the joint crossing the lap midway. My colleague says it doesn't matter.

My colleague's argument is that as long as there is sufficient lap length, the tension is transferred between the bars and the location of the joint doesn't matter. He says that a crack could open anywhere, so what's the difference between that and a construction joint - and that actually makes a lot of sense to my brain but my gut still says otherwise.

My side of things is that we don't have a single detail on any job that shows a joint through laps like that, nor have we seen one on anyone else's work, and there must be a reason for that - I just can't seem to find one in a standard.

I've never seen a contractor actually detail their joints this way on paper, but in the field if a bulkhead or form is set up in the wrong spot, it can become a thing. I insist on the contractor rectifying things to the way I expect to see them, my colleague will OK it as-is.

Do you allow construction joints to pass through lap spliced bars?