Need a book? Engineering books recommendations...

Return to index: [Subject] [Thread] [Date] [Author]

Re: Sloshing

[Subject Prev][Subject Next][Thread Prev][Thread Next]
Title: Re: Sloshing

I wouldnt think you would normally be too concerned about sloshing effects for something like a swimming pool, particularly if its a typical in-ground installation. If it is inside a building, thats another matter. If you wanted to prevent spillage from a sloshing wave in an earthquake, the freeboard requirement might put the water level enough below the deck that your client would be unhappy with the loss of function and appearance. The magnitude of the wave will also depend on the ground motion you are dealing with, and if you are talking about something like a swimming pool on top of a building, the amplification effects of the structure.

You should always check for dynamic effects and the increased water pressure for safety, but you will probably find that service level stresses and crack control requirements govern the design. For cisterns with lids, I would definitely go through the exercise of computing the sloshing wave height and making sure you have adequate freeboard. The usual design formulas are predicated on a free water surface. As soon as a sloshing wave contacts the roof of a tank, the assumption is no longer valid, and you have a trapped momentum problem that can lead to sizable increases in seismic base shear, pressure surcharges and vacuums in the tank.

I would second Bill Shermans remarks about the applicability of ACI 350.

Jim Lutz, P.E., S.E.

720 3rd Avenue, Suite 1200

Seattle, WA 98104-1820

206 505 3400 Ext 126

206 505 3406 (Fax)