Shaking table test of a 1:10 scale two-span rocking bridge with free-standing columns

Replacing traditional emulative connections of precast elements for accelerated bridge construction (ABC) with simpler discontinuities can let to more resilient structures with reduced expected damages and economic impacts after strong seismic events. This paper comprises novel shake-table tests of a 1:10 scale two-span rocking bridge with free-standing columns with proper geometrical and dynamic similarity and traditional construction materials. To excite the bridge uniformly, the experimental protocol consisted of forty-nine incremental sinusoidal ground motions that were interrupted, letting the bridge to vibrate freely to rest. The experimental results were compared with six analytical models. The results show that the structure remained undamaged after drifts as large as 6%, and did not wobble unrestricted, even though the excitations were unidirectional. Additionally, construction imperfections induced the model to rock for all excitations, including low intensity excitations, and to vibrate with periods largely divergent from theoretical equations at low displacements. This behavior took a critical role as well in the comparison between the experimental results and the estimates from the analytical models. These findings support the capacity of rocking bridges to reduce damage during seismic events despite the variability of the behavior and highlighted the need to consider possible imperfections expected at construction conditions.