Concrete Weir Design Pressures

[twilda]

If possible, how do you determine the water pressure on a concrete weir wall based on flowrate? If not, how do you go about the design of a retaining wall style of concrete weir?

 

[Ron]

The weir itself is irrelevant to the design. The wall is designed with at least the level of water that can flow over the top, and if any restraints, then design for a flow depth that exceeds the height of the wall (usually not more than a couple of inches, unless water is really channeled over a section of wall, then the whole wall becomes a crested weir).

 

[cvg]

if this is a concrete weir, use the full design water elevation over the weir which could easily be much more than a few inches. Case in point is a concrete weir with stoplogs - flow over the weir could easily be several feet deep. If you suspect wave action, add that also. If this is in a navigable channel, also include boat impact.

 

[letrab]

Depending on the depth of flow over the weir you may have to look at negative pressure on the downstream slope of the ogee. Depending on your cut off and drainage you also need to look at uplift over a length of the foundations