Effect of Skew Angle on Bridge Superstructures

In this paper, the effect of skew angle on reinforced concrete skew bridge decks is presented by using the grillage analogy. The actual deck system of the bridge is represented by an equivalent grillage of longitudinal and transverse beams. A span 26m of simply supported bridge deck is taken as the case study to obtain the values of the bending moment' s distribution versus span length for the one type of skewness and the results are compared against the moments of the right deck span of the bridge. The analysis results were based (BS5400) dead and live loads using Structural Analysis program (SAP2000). The analysis provided useful information about the variation of moments and shear forces with respect to change in skewness. It is concluded that in skew bridge deck, the bending moment is decreased, but torsional moments and shear forces are increased by increasing the skew angle. It is noticed that the maximum bending moment at skew angle 55o, by 76% in comparison with zero skew angle. On the other hand the maximum torsional moment increases for the same skew angle (55o) more than five times than with zero skew angles.