DESIGN CONSIDERATIONS REQUIRED FOR THE REINFORCED HUME PIPE CULVERTS.

A culvert is a small bridge structure of less than six metre span between faces of abutments and does not have generally two spans. The heading up of the water at the inlet should not go higher up than predetermined safe level, nor overtop the road embankment. The fixing of this level is the first step in the design and scope required to be assessed as such an opening running full gives less discharge than when running partially full. For small drainage crossings pipe culverts are often found in practice to be the most economical and easily constructed. These culverts can be easily enlarged subsequently to take more discharge by the addition of more than one or more pipes. Reinforced concrete pipes are more economical for sizes above 45 cm and under the heavy loads. The discharge through a circular opening is much more than through a rectangular opening of the same cross -sectional area, especially when running full, circular openings give more about 25 to 30 percent discharge than the rectangular. Pipe culverts should be laid on the firm bedding. The BM in circular culvert rings of pipe is treated as an arch for calculating stresses. The vertical load on half the section of the pipe treated as an arch is taken as uniformly distributed and filling over launches is neglected and the horizontal pressure is also ignored.