Torsion of a T section

[gkm111]

I'd like to first get confirmation of a torsion question.

1) The shear center is located at the intersection of the flange and web. So if the load is applied at the end of the flange the torque is load x flange width/2?

2) The maximum shear stress is located at a point most distant from the shear center? So if both legs are 2" long then the maximum shear stress will be at the end of the web?

3) If 2 is correct then how can you increase the torsional capacity of the T section?

Thanks for any assistance you can provide.

 

[BAretired]

I would not hire that company to design my swimming pool.

BA

 

[dhengr]

It appears to me that the 1.5" thk. granite tiles span about 16-18" btwn. the SS tees, and the 18" long edges in the spanning direction are free edges. Then the tiles and the tees span about 12" across the gutter too. And, these tiles are actually loose? What holds these tiles in place? I’ll bet you’ll be replacing a lot of broken tiles, and explaining broken legs to a judge. Then the first row of tiles to the left are cantilevered about 6", another potential cracking problem. What holds the row of tiles, nosing tiles, to the right in place? Is the intent that the pool slowly drains through the first two rows of tiles and their open joints, and into the gutter? I would talk with some good tile and pool contractors about some ideas of how to do this. If that’s a std. detail and they’ve used it, and it works, what are you worried about? It works. Several of us are kinda surprised that it works, for a number of different reasons.

 

[gkm111]

I've already informed them that they need to go 12" spacing. (for the 24" long slabs they want to use) They currently use the condition where there is a continuous stainless steel sheet under the entire assembly and wanted to cut the costs of such a system. I'm not quiting and will continue to suggest the HSS and the notching of the concrete, as these methods are the most durable and cost effective. however, if they continue to insist on stainless and straps then I'll give them what they want.

I've also already informed them of the case where the owner fails to maintain the pool and the stones start to move. This will be in the warnings in my notes. They actually wanted to go with 24" spacing and this is when I told them about the potential lawsuits.

 

[gkm111]

dhenger,

The lathe below would provide enough support to keep the tiles from moving, that is until frost eventually breaks this bond. The joints are also caulked except on the right side of the section allowing excess water to drain into the gutter.

Ground or poured concrete is below on the left of the section, there is no cantilevered conditions, so this is not a concern.

All the tiles, except over the gutter, are on solid ground/concrete. Caulking, plus the mesh and lathe bonds the base of the stones.

There will still be twisting of the T, so if the company still insists with their detail, I'll just simplify the detail and use 2 vertical plates spaced apart, increasing the resistance.