DISSERTATION ON BEHAVIOUR OF CONCRETE AQUEDUCT UNDER WATER PRESSURE FOR MASTER'S DEGREE IN ENGINEERING UNIVERSITY OF ROORKEE

Abstract

An aqueduct is A water carrying structure of the shape of the trough with an impervious floor and side walls. The design of sash an aqueduct oomprises of the design of the slabs resting on longitudinal beams supported on abutments, or alternatively the slab is supported on cross beams imported by main longitudinal beams parried on abutments' These two methods of designs are shown in FIG:1 and FIG :2 respectively. The large aqueducts have to provide for the road way bridge linking up the two abutments. The materials most commonly used in India are bricks or stones. In the usual course atone or brick arches span from pier to pier. In some oases plain concrete arches are constructed. :Them provide the floor of theequeduct. Stone or brick masonry walls are constructed at the ends over the face walls of the arch, of trapezoidal section sufficiently strong to take the water pressure. Such a construction, limits the span of the aroh opening and necessitates the prevision of a number of piers and the overall length anal ~width of the aqueduct are also increased oonsiderably. With the advent of Reinforced Concrete the most oonservative designs shown in WIG : 1 and 2 are adopted. The cost of each aqueducts is also high thereby making it prohibitive to use Reinforoed Concrete. A new method of designing the aqueduct is suggested in this dissertation and that is to so design the aqueduct that it behaves as a hollow beam spanning between the abutments, on the whole while the component parts are eo designed that they take r►p the secondary stresses oaased in the structure. The structure is. . 2 . made rigid enough so that it acts as a bean subjected to" transverse and lateral loadings. The question therefore arises as to whether a reinforced concrete beam whose major part is removed, mid subjected to transverse and lateral bending could behave as such and it so what should be thickness of the walls in relation to depth; and what should be the thickness of the base slab. This is the subject of investigation or the present dissertation and it may be said that more rigorous investigation should be pursued in order to come to a rational and conclusive understanding of the problem. The strains caused in the models were so small that the mechanical strain gages refused to give any reading at all and the same results were achieved even wi$41 electrical strain gages, thus proving beyond doubt that the hollow structure does behave as a beam and that its component parts are subjected to secondary stresses.