Civil Engineering - Hydraulics - Discussion

It depends upon depth because pgh formula of hydrostatic pressure and dam is constructed with different shape like gravity dam (resist by self weight) and arch dam (resist by arch action) and concrete dam etc and function of them different as per shape and when we consider the material of the dam are always different for small dam gravity and arch dam whenever big dams materials have been mass concrete like Gama material. And well said anome different water tanks have been made of different materials as concrete and thermoplastic depends also on their shape underground tank, the overhead tank also have different shapes. So it's depends upon depth, shape, and material also.

You can simply differentiate the hydrostatic force resistance by various shapes of dam as under:

1. Gravity dam:- By self weight.
2. Arch dam:- By arch action.
3. Lock Gates:- By hinges and sides.
4. Cylindrical water tank (Not considered in dam, but just for reference): Strength of cylindrical shell.

Hydrostatic pressure at any point in a liquid depends only on the depth and density of a liquid. But hydrostatic pressure 'on a dam' is the sum of pressure by liquid acting on the surface in contact with liquid within the dam. So it depends on the depth as well as the shape of a dam.

@All.

As you all said P=yh does not depend on shape because you already assuming that dam's upstream face is vertical. But what if the upstream face is not vertical.

You have to solve the pressure as you did in the hydrostatic pressure chapter in fluid mechanics.

If it is pressure intensity, it depends on depth only. If it is pressure force it depends on depth, shape and length. I think the question should be hydrostatic pressure per unit length.

So, the given answer is correct.

@Peshal

Here, h depends upon shape so every shape has a different value of h. So pressure varies with shape also as for concerned to dams.

Pressure depends upon depth only not a shape. If any shape is there it varies linearly only. Hence answer is only option b.

Because Hydrostatic pressure increases with Depth from Hydrostatic Law and also depends on shape of the dam.

Depends on material also na? Because hydrostatic pressure depends on gama of material.

Haydrostatic pressure increase with depth and also shape create a pressure variation.