Probabilistic seismic assessment of a new elastoplastic column-deck joint on the prefabricated frame-bridge

The prefabricated frame-bridge is a new type of structure in response to the problem of difficult land acquisition in the expressway reconstruction and expansion. Considering that the pre-stressed columns are the main load-bearing components, which are difficult to be repaired after damage, so an energy dissipation member, i.e. elastoplastic column-deck joint (EC-DJ) is developed to connect the deck and column. In this paper, the impacts of EC-DJ on the failure probability of pre-stressed columns are investigated through the fragility analysis methodology. Firstly, the damage indexes under different states of EC-DJ are defined by the fiber section model. Then the optimal intensity measures (IMs) of probabilistic seismic demand models for components subjected to far-field ground motions are identified. Moreover, a full-scale experiment model is carried out to verify the correctness and applicability of the finite element model. Considering that the ductility of EC-DJ can be fully utilized to protect the column, the influence of EC-DJ on the structure is investigated accounting for different configurations of EC-DJ including steel ratio, section size, and reinforcement ratio. The results show that the improved EC-DJ can be used as "fuse member" in the structure, which can dissipate much seismic energy for the prefabricated frame-bridge so the pre-stressed columns can be protected. Furthermore, it is an economical connection with repeatability, which is convenient to be repaired after damage.