Abstract:
This thesis describes theoretical and experimental analyses of curved box-girder bridges. An elastic model of a two span continuous, single cell, curved box-girder of reasonably typical plan and sectional geometry was constructed of segments cast of epoxy resin. Two ducts were cast in each web so that the model could be prestressed. One span was heavily strain gauged. Surface stresses and deck slab deflections are presented for a number of load cases including single wheel loads, combinations of wheel loads, truck loads, and prestress. Computer programs were written to enable the static load analysis of curved box-girders by both finite strip and finite element techniques. In the case of the finite strip method, the traditional curved strip approach was extended by the inclusion of an auxiliary nodal line permitting higher order displacement polynomials to be used. Strip load vectors for a variety of load conditions were formulated and a segmental scheme was adopted to represent prestress forces. The results of analyses of the model bridge for a number of load cases, including prestress, generally show good correlation with the experimental results. In the finite element idealization the box-girder bridge was assumed to be a thin spatial plate structure. Constant thickness quadrilateral elements giving six degrees of freedom at each node — three displacements and three rotations — were employed. Results of analyses of the model bridge for four load cases with relatively course mesh representations are presented. Again these generally compare well with the experimental results. The effects of curvature on the structural response of single cell box-girders to static loads are also examined.