ANALYSIS OF SKEW EFFECTS ON T-GIRDER BRIDGES

Abstract

evelopmental interest all over world requires high degree of mobility. The phenomenal growth of the industrialization in last three decades has resulted in a great increase in vehicular traffic on roads and bridges. To this end, the bridges are required to withstand the heavy loads imposed by modern heavy vehicles with utmost safety and economy Bridges at varying skew angle and with some curve are frequently observed to provide the most suitable alignments. In the past, there has been a general tendency to align the bridges at right angle to the river flow by introducing long approach roads. This results in increase in path distance to travel and also in traffic problems. For long trailors, also, it is difficult to negotiate the horizontal curves even at low velocity. Hence to catch the requirements of the high speed and stern safety measures of present heavy highway traffic it has become immensely important to minimize the number of horizontal curves in the highway alignments. This requires the construction of skew bridges. Slab girder bridges are economical and suitable for the short spans ranging from 10 to 25 metres. This has necessitated better understanding and analysis of structural behaviour of skew slab girder bridges. During recent years the FEM has developed as a powerful computational tool for continuum problems and is specially suited to structural analysis problems. This work involves the parametric study of the skew angle on the structural behaviour Skew T-Girder Bridges using FEM. Here the emphasis is given on the effect of varying skew on the structural behaviour of the main girders under the action of dead and IRC vehicle loading. . The design parameters shear force, bending moment, torsion and deflection of main beams of T- girder bridges are considered and effect of varying skew angle on these is discussed. Some bridge problems for right bridge solved in standard books were chosen and were analyzed by FEM based software ANSYS 8.0 and after their validation; the skew bridges are analyzed on the same line. For better comparison of the skew effects, the parameters girder shear, torsion, bending moment, values have been presented in the tabular as well as in graphical form. Appropriate conclusions have been arrived at, based on logical discussions. iii