Loads acting on a Dams

list of all possible forces acting on a dam are as follows;

Self weight of the dam:

It is the weight of the dam due to the action of the gravity and always acts downward direction through CG of the body. The self weight of the dam depends upon the specific weight of the construction materials.

Hydrostatic pressure:

It is the pressure exerted by the fluid of the dam body and always acts perpendicular to the contact surface. The resultant pressure acts through the centre of pressure.

Uplift pressure:

It is pressure exerted by the fluid on the dam surface from the underneath and always acts towards the upward direction. The water enters in to the dam body through the pores, cracks, fissures and causes the uplift pressure. The uplift force will reduce the effective weight of the dam and depends the contact area where it acts. The magnitude of the uplift pressure will depend upon the types of the foundation, drainage provision, provision of the cutoff walls, grouting etc.

Earthquake pressure:

It is the pressure exerted on the dam body due to acceleration wave of the earthquake. The wave acceleration direction may be vertical, horizontal as well as in inclined direction too.

Wind pressure:

It is the pressure exerted by the wind on the exposed surface of the dam surface. The wind pressure depends upon the intensity of the wind velocity.

Wave pressure:

It is the pressure exerted by the action of the wave on the dam surface. The wave force depends upon the height of wave. The height of wave in the reservoir depends upon the velocity of the wind and the fetching height (distance from the dam up to the end of backwater curve).

Silt pressure:

It is the pressure exerted by the silt accumulated behind the dam and could be evaluated through the Rankine’s active earth pressure theory.

Ice pressure:

It is the pressure exerted by the ice on the dam surface. It depends upon the thickness, temperature fluctuation and restrain of the resisting force.

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