Seismic assessment of elastomeric bearings in concrete box girder bridges considering site conditions

Introduction: Bridges are structures that require significant investments and are vital for the economic development of any country; their proper performance during and after an earthquake of considerable magnitude is critical to responding to emergencies arising from the event and ensuring rapid economic recovery of the affected areas. In the national context, reinforced elastomeric bearings are the most used connection elements between the superstructure and the substructure due to their low cost compared to other available systems. However, the requirements in the Colombian bridge standard exclusively consider dead loads and live loads in the serviceability limit state without additional requirements for evaluation of the seismic performance of this type of connection elements. Objective: The study's primary goal is to compare the Colombian bridge standard and Eurocode regarding elastomeric bearings design guidelines to determine the standard that produces an elastomeric bearing design with better performance regarding seismic events. Method: Considering the most common bridge typology within the Colombian context, computational models of box girder bridges were developed with constant lengths but with variations in the position and height of the intermediate supports. The numerical models include the effects of the stiffness contribution of each type of elastomeric bearing regarding bridge standard guidelines, allowing the comparison of the performance of the elastomeric bearings during seismic events. Results: It was possible to determine the design guidelines and considerations that produce elastomeric bearings with better performance during seismic events regarding displacements. Conclusions: Lower displacement values and, therefore, better seismic performance are evident for the dimensions of the elastomeric bearings designed by the Eurocode.