Stability Analysis of ‘L-Shaped’ PSC Box Girder Bridge

The structural behaviour of box girder is complicated, which is difficult to analyse in its actual conditions by conventional methods. Prestress technology has been a part of the ‘Bridge Design Practice Manual’ since the1960 edition. Over the years, revisions and updates have been made. Again, there is a need for updating. This edition reflects revised friction coefficients and detailed computer output.

In present study a two lane, two cell box girder bridge made up of prestressed concrete is analysed for moving loads as per IRC:6 recommendations, Prestressed Code (IS: 1343) and also as per IRC: 18 specifications. The analysis of PSC box girder using ‘SAP 2000-12 Bridge wizard’. The various span/depth ratios considered to get the proportioning depth at which stresses criteria and deflection criteria get satisfied.

The contribution of prestressing steel is incorporated, while the material and geometric nonlinear analysis of plane prestressed concrete frames including the time dependent effects due to load & temperature history, creep, shrinkage, and aging of concrete and relaxation of prestress were also considered. For the construction stage analysis, many sophisticated computer programs for the analysis of segmentally erected prestressed concrete bridges considering the time-dependent effects of concrete has been developed to predict the bridge response.

Prestressing tendons may be stressed, prestressed, and removed, while a traveling formwork can be modelled. However, most computer programs have some limitations in wide use because of complexities in practical applications.

Keywords: Concrete Box Girder Bridge, Prestress Force, Eccentricity, Prestress Losses, Reinforcement, Tendons, Flexure strength, shear strength,Analysisand computation. SAP Model.