Limit State Design Of RCC Skew Girder Bridge

Abstract

Present situation of trafic requirements demand safety requirement and in- clined alignment of road in view of the trafic speed and this in turn necessi- ties the use of skew bridge. Skew bridge is also necessary in such area where alignment can not be changed due to topography or due to space constrains. Skew bridge is also necessary in such area when road alignment crosses the river or rail other than 90. Skew bridges are usually consists of precast girder with in-situ deck slab and diaphragm or in-situ girder with deck slab and diaphragm. There are many methods available for analysis of superstructure subjected to Live load namely Courbans Method, Orthotropic Plate Theory, Finite Ele- ment Method, Finite Diference Method, Grillage Analogy etc. In the present study two namely methods, Grillage Analogy and Finite Element Modeling are considered for analysis of bridge superstructure. Diferent loads consid- ered for analysis of superstructure are Dead load, Super imposed dead load, Vehicle load including IRC-70R (wheeled) vehicle and class A (Wheeled) ve- hicle. Analysis of superstructure using Grillage Analogy is done with the help of STAAD.Pro software while CSi Bridge module of SAP software is used to implement FE Modeling of superstructure. In the present study precast T-girder type bridge superstructure is consid- ered. Analysis of superstructure of Bridge is carried out using both the methods of analysis described earlier. Design of superstructure is carried out using Limit state design based on IRC:112-2011. Note that, Limit state method is lately appear to bridge design as compared to conventional struc- tures. Parametric study to determine e ect of skew angle ranging from 0 to 60 with an interval of 15 is carried out for Bridge with span varies from 12m to 24m with an interval of 4m with varying spacing of girder from 2.5m to 3m at an interval of 0.25m with 12.9m total carriage way width and 9m clear carriage way width. It has been found that diferent parameters like Support reaction, Shear force, Bending moment, Twisting moment and Displacement at diferent location in girder and slab.