Design Of RCC Box Girder Type Bridge Superstructure, Plate Wall Pier & Open Foundation Using IRC:112-2011

Abstract

Box Girder bridges are more economical & aesthetically good for larger span. It can resist the high amount of Torsional Moment compared to Open Sections. On the other hand the Analysis & Design of the Box section requires more effort compared to Open Sections. For more than four decades, the design of R.C.C. Bridge is carried out by using IRC- 21 (Working Stress Method). Recently IRC has come-up with IRC 112 based on Limit State Design philosophy. Considering wide scope of subject, present study has been restricted to design of Box Girder type Superstructure, Plate wall type Pier & Open Foundation using IRC 112- 2011. Structural design has been carried out considering the Ultimate Limit State (ULS) of exure, shear and torsion and Serviceability Limit State (SLS) of crack width and de ection. Present study has been divided in two parts. First part includes theoretical study for understanding the codal provision for Ultimate Limit State & Serviceability Limit State of IRC: 112-2011. Second part includes analytical study covering detail analysis & design (by LSM) of Super-structure and Sub-structure. Analysis of Super-structure is performed using CSi Bridge Software (based on FEM). Sub-structure analysis is carried out manually for forces like Dead Load, Live Load, Braking Force, Seismic Force, and Wind Force. Load combinations are considered based on IRC: 6-2014 for strength, serviceability & equilibrium condition. Design of Super-structure (Box-Girder) based on IRC:112-2011 is divided in main three components which consider design of Deck slab based on transverse analysis, Design of Bottom soft slab (Longitudinal analysis) & Design of Exterior and Interior Web considering out of plane bending moment in both direction & shear. Design of Sub-structure is divided in three sub-parts which includes Pier Cap, Plate Wall Pier and Open Foundation. The parametric study for superstructure is performed with two alternatives: First one is Span variation from 20 m to 40 m and Second one is Depth variation with change in Grade of Concrete between M25 to M40. The Parametric study of Superstructure revealed the economical span to depth ratio with different grades of concrete for span ranging from 20m to 40 m is 11.90 to 20 Quantity of materials and rate analysis of each alternatives is carried out to arrive at cost of bridge including Super-structure and Sub-structure.