Curvature Limitations In Bridge Codes

<p>In recent years, horizontally curved bridges have been widely used in congested urban areas, where multi- level interchange structures are necessary for modem highways. A series of horizontally curved bridges were analyzed in this study using a commercial finite-element program, ABAQUS. In each analysis, the behavior of bridges was investigated, and the major internal forces developed in the members were determined. Specifically, stresses, vertical deflections, vertical reactions and natural frequencies for different values of the horizontal angle of curvature. These values compared with the values of a straight bridge of similar span and cross-section configuration. Bridges taken into account were single and twospan horizontally curved concrete slab bridges, concrete T -beam bridges, concrete cellular bridges, concrete box girder bridges, slab-on-steel !-girder bridges, and composite steel box girder bridges. The design parameters considered were degree of curvature, span length, number of lanes, number of girders and/or boxes, and span-to-depth ratio. The stipulation made in bridge codes for treating a curved bridge as straight one is examined. Based on the data generated from the parametric study, sets of empirical expressions were developed to evaluate stress, deflection, reaction, and frequency distribution factors in a curved bridge system as related to a straight bridge system. Then these expressions were extended to establish more reliable expressions for curvature limitation to treat a curved bridge as straight one.  </p>