Question

Classify dams according to their structural design by giving typical cross
sections and plans.

Answer 1

Dams are mainly classified into

1.Gravity Dam

2.Arch dam

3.Buttress Dam

4.Steel Dam

5.Timber Dam

6.Earth Dam

Gravity Dam

• External forces are resisted by the weight of the dam
• Constructed either by masonry or concrete
• More strong and stable
• Can be constructed of any height, the world largest dam is a gravity dam

Arch Dam

• Curved in plan and bears a major part of the loads by transferring it to abutments by arch action.
• Balance of the load is transferred to the foundation by cantilever action
• As the load transferred to the foundation is less, arch dams can be constructed on moderate foundations also
• For a given height, the section of an arch dam is much lesser than a gravity dam

Buttress Dam

• Buttress dam consists of a number of buttress or piers dividing the space to be dammed into a number of spans
• Water is retained by the panels of horizontal or flat slabs.​​​​​​​

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Steel Dam

• Dams are constructed with a framework of steel with a skid plate as a deck slab on the u/s side

• Using modern methods steel fabrication can be done quickly

• Cheaper than other rigid dams

• Stresses in steel dams can be easily determined and hence the design is easy

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Timber Dam

• Constructed with a framework of struts and beams with timber plank facing to resist the water pressure

• Suitable for any type of foundation

• Most suitable as a temporary dam

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Earth Dam

• Earth dams are made of locally available materials, soils, and gravels
• Most common types of dams used up to moderate heights
• The foundation requirements are less stringent than for other types.​​​​​​​