A review on the seismic behaviour of irregular bridges

This paper presents an up-to-date state-of-the-art review on the behaviour of irregular bridges under seismic excitation. Although several characteristics and definitions may be applicable to the regularity of bridge structures, almost all the published literature referencing the term 'irregular bridge' focuses on a specific class of straight reinforced concrete (RC) bridge with unequal pier heights as the main source of irregularity along the bridge length. Several successive as well as interrupted research works on the subject have been reported during the last two decades. Among significant developments under continuous progress in this field, two main advancements can be recognised: (a) the development of displacement-based design methodology; (b) further understanding of the higher modes effects, which reflects the adequacy of different analysis methods for irregular bridges. However, a review of the literature reveals that works being actively conducted on this subject are still inadequate and hence deserve further attention in future research to gain a better awareness of the seismic performance of irregular bridges, in order to provide simply applicable and more definitive guidelines for actual design purposes.