"AN EXPERIMENTAL STUDY OF SKEW FOOTINGS RESTING ON COHESIONLESS SOIL"

ABSTRACT Provision of skew footing in the design of foundation of a bridge becomes very essential whenever it crosses to a railway line, canal or river with a skew angle more than 60 degree. For the purpose of design to a skew footing, different parameters are required. In this study, the author had attempted to investigate the behavior of such footings experimentally. In the present study, an effort has been made for the stability and settlement behavior of the skew model footings of width, B = 60 mm, 80 mm and 120 mm each having skew angles of 10o, 15o and 25o resting on bed of Sandy soil. For bridges on straight alignments with support skews exceeding 60 degrees, the designer should select to use a skew footing while designing a bridge foundation to more accurately capture true load distribution on sub-soil base. For the superstructure, it was assumed that support skew does not affect the distribution of loading response across the section with the exception of shear. In a skewed bridge, loads tend to distribute to the supports in a direction normal to the supports. In this study, a small model footings tests were conducted on Sandy soil layers by taking three sizes of skew footings of 60 mm, 80 mm and 120 mm each having skew angle of 100, 150 and 250. The settlement aspect of the problem has also been analyzed and a new approach, incorporating the concept of load intensity and settlement has been suggested, for the prediction of settlement of the prototype, on the basis of small-scale model tests. The value of predicted settlements for skew footings, by proposed method has been found to be much closer to the observed values of settlements.