a. function weir
The function of the weir (weir), among others:
1) In a small discharge weir should close the river and raise the water level.
2) In a large discharge of water partially drawn and most will cross back weir, so this serves as a dam like peluap.
b. Terms Construction weir
1) weirs must be stable (especially against water pressure),
2) Can withstand leak (danger piping),
3) Elevation backs weir should qualify the needs of irrigation areas served,
4) The dam water level as low as possible,
5) The cost of manufacture and manufacture as cheaply as possible,
6) Form peluap should be such as rock and sand can be dropped at the bottom of the river downstream without damaging the construction.
c. Miscellaneous The weir by Location
Based on its location, the dam can be divided into:
1) dam on the river. Weir on the river been on the river straight.
2) dam on Caupure. Weir on caupure built if encountered sharp turn part of the river and back again.
Things That Can Ruin weirs And How to Overcome It
Is leaked through the bottom of the structure with a speed which is quite large, so the potential to bring the soil particles. The damage that occurs is the rottenness of the soil under the structure that will result in broken or destroyed structure. Attempts to avoid that is by far the flow rate of piping which can be done by:
– Making floor face
– Making plaster
2) Damage to the lower floor
Caused harm in a matter or assumptions. The floor can be damaged due to turbulence / eddy (Kolk) by the flow. This can be overcome with the correct count of hydraulics.
3) breach of the dam body
That is due to the tensile stress due to errors in the design due to the resultant force acting located outside terrace. This can be overcome by the dimension or shape due to the forces acting on the terrace.
4) scours the sand / silt in the dam
To overcome this required concrete strength is strong enough to withstand scouring the water with a certain thickness (± 30 cm).
Stability problems due to the water pressure is too great, for it was the water pressure needs to be reduced by splitting water energy upfront weir.