An aqueduct is a structure carries canal water through it and crosses over a natural drainage river or nallah. An aqueduct is provided when canal bed level is higher than HFL of natural drainage.
In case of open through aqueduct the service road is discontinuous, and during rainy season for inspection of aqueduct site engineer has pass through submersible causeway to downstream side aqueduct. In this case cost of aqueduct and cost of the causeway and service road is to be borne by irrigation department. But during heavy flood the water flow over cause way and it can not be possible to inspect aqueduct for throughout length. Hence closed box aqueduct is proposed in place of existing open trough aqueduct.
A typical type of aqueduct class as a trough in which one case is considered as overhang box trough and other case as single box trough. In both case service road of canal is pass over top of trough maintaining the continuity of road from one end of aqueduct to another end aqueduct. Components of trough are base slab, vertical wall and top slab are designed for both cases and overhang box trough is found economical.
The sub structure of aqueduct such as pier, abutment, and transition wall are also designed. It has been found that cost of structure increase by 25% if closed box trough constructed instead of open box trough. It shows that for continuity of service road from one end to other end of aqueduct structure the increase in construction cost by 25%.
We are thankful to Mr Abhijeet Narde for submitting this post to us as on August 11, 2009
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