COST COMPARISON OF R.C. BOX GIRDER BRIDGES

Abstract

Reinforced and Prestressed concrete box girder construction has been widely used world over for the construction of bridges and flyovers. Because of the large inherent torsional rigidity of such sections they are especially suitable for bridges curved in both plan and elevation and are found to be highly economical for the medium and long spans in comparison to the conventional open girder sections. In the conventional design of box girders, a section of the bridge is assumed for the analysis and the section is checked for the maximum stress resultants to ensure the safety of the design. It is almost impossible to guess a cross-section for given span, width of roadway and the other site conditions which is not only safe but involves the minimum amount of construction material. Till now, the choice of the initial cross-section of a R.C. box girder bridge has generally been a matter of experience as the enough and adequate guide lines are not available. No worthwhile guide lines are available especially for the choice of number of cells to be opted in a box section for a multi lane bridge which leads to the most economical solution. The purpose of this work is to undertake a rational study to generate suitable data base to facilitate the choice of the box section for the given conditions much easier. Further, since the study warrants that a sufficiently large number of cases are investigated to arrive at some meaningful • inference, it is utmost important that suitable software be developed for automated computer aided analysis and design of the box section, A design computer program 'Box' compatible with an existing anal program module 'SHELL' has been develop