Joint irregularity in the seismic behavior of highway bridges

Taking into account previous studies of bridges with irregularity in the superstructure or in the substructure, new models have been generated with irregularity in both systems. The group of studied bridges presented degrees of curvature between 0 and 180 degrees, each 30 degrees, and ratios of the extreme to the central span length of 1:0.25, 1:0.50, 1:0.75, 1:1.25, 1:1.50, 1:1.75 and 1:2.00. The irregularity, considering both systems, is analyzed by changing the length of an extreme or central pier in percentages of +/- 0.25%, 0.50% and 0.75%. Models with joint irregularity have been analyzed elastically using a database of 53 accelerograms registered in the most seismic hazardous zone of Mexico. Dynamic analyses were developed to evaluate the maximum responses obtained with the elastic analyses, mainly in displacements or mechanical elements, grouped by statistical quartiles. The quartiles obtained with different irregular configurations only in the superstructure, were compared with those found for different irregular joint configurations. Recommendations were generated for bridges with joint irregularity.