Wind load and wind Effect on Spillway gates 1

[SKJ25POL]

Is wind load a concern on spillway gates when the are raised?
What problems wind can cause?

I am new to this subject, any information from experienced people will be greatly appreciates.

Sincerely,

 

[jayrod12]

I'd say yes you would need to check the spillway gate supports for the lateral load that would be applied by the wind. It may not be an issue.

 

[racookpe1978]

High winds can break things. Bend things. Jam (prevent movement) if the motors/hydraulics are too weak to move against the friction/bending forces.

But, you've got to calculate the real loads: Every dam is going to be in a valley ,on the ground itself, and the spillway gates are actually below the highest ground (the dam lip) behind retainers and gate guides. It is physically impossible for them to be hit by the extreme winds above ground above a hillside up a tower.

But ... The dam IS across a valley and so will tend to channel winds at certain times of the year up and across the top of the dam. Sideways (CA's extreme desert winds) forces may also come down the nearby mountains and sweep across the lip.

So. Go look up the past weather history for your site. Draw your geometry and figure out a reasonable factor. Do the math. Ask your boss what your company contract requirements are. Chances are, they will not include having to open or close spillway gates during a hurricane or tornado.

 

[DamsInc]

It depends on the type of gates, its supports and the dam itself. In most cases, the hydrostatic pressure on the gates is going to be far higher than any wind loads. But there are situations where it could present problems. How is the gate supported in the raised position? How large is the gate? There are a lot of variables here.

But, you've got to calculate the real loads: Every dam is going to be in a valley ,on the ground itself, and the spillway gates are actually below the highest ground (the dam lip) behind retainers and gate guides. It is physically impossible for them to be hit by the extreme winds above ground above a hillside up a tower.

I disagree. Not every dam is in a valley. In fact, I would argue that most dams are not in valleys.

 

[btrueblood]

"I would argue that most dams are not in valleys. "

What purpose do they serve then? A dam on flat ground, or on a mountaintop, or under the ocean, would seem to not be doing much damming.

 

[msquared48]

That statement seems strange to me too. If they are not in a valley or floodplain, how do they retain water?

Back to the OP'S question... Most dams have hydraulic model tests, and large structures wind to tunnel tests. Depending on your project, that could be warranted. As previously mentioned, the wind can vary greatly depending on the direction and topography.

Mike McCann, PE, SE (WA)

 

[DamsInc]

I was trying to say that a dam doesn't necessarily only occur between two hills along a channel which would funnel wind across the top of the dam. It could be in an open floodplain like you said, or any area which water drains into but isn't necessarily shielded by wind. Depends on your definition of a valley I suppose. In any case not really relevant to the question.

If the gate is cantilevered above the dam in the open position, then yes I would check wind to ensure the supports are strong enough to hold it. Some rough calcs should be able to tell you if wind is a load which could govern in a situation.