Deck

[ladygrniz]

I hope this is the right place...if not, I'm sure I'll be directed to the one that is...
My question is: What is the purpose of the top seat (top rail) and the Seat cover (connector). The 'seat' is one that can be sat on without damage to the walls. Our pool (just in case the description didn't show up with my post) is a 15x30 AGP 54" Zanzibar, we've had it for almost 2 years and now want to put a deck around it. We want it to go OVER the top rail, and I get that when we have to replace the liner it'll be a pain to remove the stuff to get to it. SO, my question is, if we're going to put the deck OVER the top of the pool, why do we need the top rail? Does it provide any other support for the pool or is it there for aesthetic value and support for swimmers who grab the sides? Thanks in advance.

 

[woodyp]

I think if nothing else, the top rail helps distribute any forces on the pool wall (laterally, not vertically) between more than one post. Other than that, it's a good place to sit a drink on!

 

[ladygrniz]

Thank you for the logical reply, but not its not a definite answer and I really need to have one because I want to ditch the rails! I did find this and am still looking for more information. The author states it's for the structure, but never specifies.
[h=2]Top Ledge[/h] Also known as that thing your kids jump off of into the pool (by the way, not recommended.) The top ledge is more than a step for your daredevil 8-year-old; it is part of the safety, structure and aesthetic design of the pool.
The top ledge is a 5 – 8” wide plank made of steel, resin or aluminum that spans the wall’s top edge between uprights. A top cap snaps to each end of the ledge to cover each upright section. The purpose of the ledge is to hide the top rims and wall edge (surprisingly sharp) from swimmers whilst entering and exiting the pool. The ledge also acts as a mooring point for securing pool steps, railings and ladders.
There is no set time for top ledges to last on a pool. A lot has to do with the material the ledge is constructed of; aluminum will last the longest, then resin and steel brings up the rear. Even with weather coating, steel will rust from rigorous use that can scratch it coated surfaces to reach the raw metal. If your pool is salt water or you are considering a switch to it, forget about it. Salt water will oxidize the steel top ledges faster than your wallet can replace them.

 

[gwegan]

Lets be direct. Do not omit any of the structural parts of an AGP. None. zero, zilch.

Omitting the calculus here is an explanation:

The top rail, especially in your oval configuration, spreads the forces from the weaker parts of the pool to the stronger parts of the pool. Any above ground pool is a contest between gravity working on the mass of water in the pool and the walls of the pool. In a round pool those walls forces are equal all around the pool and the pool's counterforce is equal too. In a round pool the top rail provides stability and keeps the pool from deforming so it stays round and strong. If someone hits the side hard it distributes the energy of that hit around the side of the pool. In a round pool the mass of the water is helping keep the pool round and adsorbing some of that force. Does that make sense? But you need the top plate (that is what it is to an engineer) to help distribute those forces and stiffen the side wall.



In an oval pool its even more critical because while the force of the water trying to escape all along the walls is equal, the counterforce produced by the wall structure is not equal. The long sides are weaker, just as the long sides in a cardboard box are weaker. Its stronger at the corners. The top rail (plate) stiffens the walls so they are stronger and can transport the force of the big old fat guy crashing into the pool wall while trying to impress the kids around the pool wall and not allow a collapse.

When they designed your pool they did the math to determine those forces and included the top rail in the calculations. Since it was in the calculations you need to include it in the pool.

Does that make sense? So don't omit the top rail.

Complete the test in pool school and me a Margarita Machine and I'll send you an AGP engineering certificate which can be traded in for a Reases pennut butter cups at the HyVee store in suburban Kansas City.

 

[ladygrniz]

gwegan, thank you. I just now saw this reply. We haven't had time to do anything with the pool just yet, so it's fortuitous (I like using big words now and again...) that I found this now. I do understand the logic behind your explanation, sort of. It's a bit difficult for me to see it, though, since the railings don't even touch the rim of the pool and the big ole' fat guy can still crash into the sides and cause that force to impact the walls. At any rate, I'm appreciative for the scientific/physics explanation, it gives us something to seriously ponder. It would be so much easier, if not safer, to ditch the railings so our deck can go over the top and we still would have easier access to the lining if/when it needs to be replaced. Oh well, life is hard and then you die. Might as well stop whining and do what's safe! Thanks again.