Statistical analyses of effective lengths in steel arch bridges

This study conducts a quantitative investigation of the effective lengths of arch bridges using three-dimensional buckling and statistical analyses. Three analytical models of parabolic steel arch bridges including inclined, tied and deck-type arch bridges were studied. This paper indicates that changing bridge boundary conditions to force the global translation mode being the first mode can be used to obtain the effective lengths in the two local directions. Moreover, assuming a constant axial force of the arch to perform the buckling analysis is acceptable. Then, more than 25,000 three-dimensional buckling analyses with a broad range of bridge parameters were performed to obtain six statistical formulas with acceptable accuracy. The numerical results also indicate that the effective length estimated by the AASHTO specifications is conservative.