Dynamic and static analyses of continuous curved composite multiple-box girder bridges

Horizontally curved concrete deck on multiple steel box girder bridges is a structurally efficient, economic, and aesthetically pleasing method of supporting curved roadway systems. Modern highway constructions are often in need of bridges with horizontally curved alignments due to the tight geometry restrictions. Continuous curved composite box girder bridges allow for the use of longer spans, thus reducing costs of the substructure.; Despite all inherent advantages of continuous curved composite box girder bridges, they do pose challenging problems for engineers in calculating the load distribution due to moving vehicles across the bridges. Curved bridges are subjected to high torsional as well as flexural stresses. The interaction between the box girders is also more complicated in curved bridges than that in straight bridges. North American codes for bridges have recommended expressions for the load distribution factors only for straight bridges and not for curved bridges. Impact factors proposed in these codes are generally restricted also to straight bridges. In addition, simplified formula to predict the fundamental frequency of analyzing the bridges is not available. To assist engineers in dealing with the complexities of continuous curved composite box girder bridges, a reliable, accurate, and simple method is required to calculate the structure's response under self-weight and vehicular loading.; The refined three-dimensional finite-element analysis method is employed to investigate the static and dynamic responses of the bridge. Two two-equal-span two-box physical bridge models were constructed in the laboratory. One of the bridge models was straight in plan while the other was horizontally curved. The physical models were tested under several static loading cases to better comprehend their elastic behaviour. Free-vibration tests were also conducted to obtain the natural frequencies and the corresponding mode shapes of the bridge models. Both models were loaded up to failure to examine the collapse mechanism and its correlation with the finite element modeling. Findings obtained from the two physical bridge models were compared to those predicted by the analytical models. The agreement between the finite element model and the experimental model made it possible to use the analytical models to conduct three parametric studies on several bridges.