Finite Element Modeling and Analysis of Bridge Super-structure

Abstract

With the spreading use of the electronic digital computer there has been a revolution in methods of structural analysis, which is in general has been a boon to the engineer. However, it has led to difficulty in decisions for the engineer when one has to select the most appropriate method for a particular problem. Bridges form vital links in the communication system and the need to build bridges across wide rivers with alluvial and scourable beds, deep gorges, open seas and grade separators on urban highways, calls for the solution of a multitude of engineering problems. Bridge analysis and design at all over the world has undergone remarkable changes in the past two decades. The increased demand for complex roadway alignments, advances in computer technology for bridge analysis and design, are some of the factors for these developments. Normally the bridges are constructed straight for simplicity of construction and design, but sometimes the site condition for bridge is such that it is not possible to have straight bridge. In such case it is necessary to construct the skew or curve bridge. It is relatively easy to analyse the straight bridge but when the bridge is skew or curve, the analysis is somewhat difficult. Analysis of skew or curve bridge is carried out using computer programs that incorporate various analysis methods like finite element analysis. SAP 2000 is one of such computer programs which has been used in present study for the analysis of bridge superstructure. In present study for bridge analysis the finite element method is used. Here, in this study two types of bridge are considered slab bridge and girder type bridge. In the slab bridge two types of configurations are taken namely skew slab bridge and curved Slab Bridge. For the girder type bridge skew type bridge is selected. In the parametric study of skew bridge the skew angle is varied from 0° to 20°. In curve bridge the sectorial angle is varied from 0° to 45° and aspect ratio is taken as 0.5, 1.0, 1.5 and 2.0. In skew slab bridge different parameters are studied such as variation of shear force and torsional moment at acute and obtuse corner of bridge. Variation of maximum span moment and deflection of bridge are studied for different skew angles. iv In curve slab bridge the effect of curvature and aspect ratio has been studied in terms of span moment, torsional moment and deflection. In skew girder type bridge the finite element analysis results are compared with different methods of analysis. The comparison is carried out in terms of span moment, deflection and shear force in longitudinal girders. Chapter 1 includes the introductory part of thesis, the classification of bridges, various types of loading that can occur on bridge superstructure, and finite element analysis of bridge. Chapter 2 describes the literature review based on the finite element analysis of bridge, grillage analysis of bridges, finite element analysis of skew and curved slab and girder type of bridges. Chapter 3 includes the introductory part about SAP2000 and finite element modeling and analysis of bridge superstructure using SAP2000. Chapter 4 includes finite element modeling and analysis of slab type bridge superstructure for different skew angles with different discretisation. Chapter 5 includes finite element modeling and analysis of curve slab bridge superstructure for different sectorial angle (q) from 0° to 45° and for different aspect ratios (0.5 to 2.0). Chapter 6 includes finite element modeling and analysis of girder type bridge superstructure for different skew angles form 0° to 20° skew angles Chapter 7 includes summary of wok, conclusion and further scope of work.