Design Of Box Type Multibarrel Skew Culvert

Abstract

As the numbers of bridges comes up it has become healthy to provide box type multibarrel skew culvert where traffic moves on the top of continuous slab and water flows through barrels underneath it. Present situation of traffic requirements demand straight alignment of road in view of the fast traffic and this in turn necessities the use of skew crossings. By providing this type of alternatives, bridge span is in direction of road, we can directly provide skew culvert. So there is no need for provide approaches on both side in form of curve which will solve land acquisition problem and project becomes faster and economical. Modeling and analysis of the skew bridge deck and box is to be done in Staad- Pro and/or in SAP. For single cell analysis STAAD PRO is used and for multibarrel box with SAP 2000 is used. For single cell analysis separate worked out in spread sheet with considering all load combination guided in IRC-6. The problem consisting of two lane road width (7.5m) and span of 20m. Each barrel is dimension has 5m by 5m. For dead load, live load, earth pressure, water pressures are considering and for various load combination it will be analyzed and for critical design will be made. For analysis of single cell with skew angle of 25 degree generalized spread sheet was made and accordingly analysis processed. Culvert is designed for 25 degree skewness and for four barrels. Further comparative study is carried out for different skew angles 20 degree, 25 degree, 30 degree, 40 degree. Parametric study also done for the give problem statement by considering various skew angles for comparing twisting moments. Another study done for different soil bearing capacity comparing to the bending moment for the base slab. Also parametric study done for different support condition on base slab which shows for even smaller height structures when we incorporating the soil structure interaction with soil stiffness, base moment will reduce and so that obtaining less thickness and less steel for base slab which economize the project cost.