Summary
When designing a bridge subjected to seismic loading, the ductility capacity of the elements that are expected to enter the inelastic range must be defined. To achieve this, the engineer consults design recommendations or codes, but many times these recommendations vary from code to code or are insufficient because they only consider a few typologies. This paper analyzes the ductility capacity of piers and columns of a common urban bridge, composed of a superstructure of concrete slab and AASTHO-type beams, on a substructure of single or multiple reinforced concrete piers. From this type of bridge, different element heights and medium and high ductility behavior levels are analyzed using static and dynamic nonlinear methods. For this, it is also considered that the structures are located on three different types of soil (rigid, transition and soft) with soil characteristics of Mexico City and with the inclusion of the soil-structure interaction effect. The models made are designed according to local design requirements and push-over analyzes are carried out to define the capacity curve, through which the ductility capacity is determined. Additionally, step-by-step dynamic analyzes are carried out with a base of ten characteristic earthquakes of each type of soil, scaled to obtain the same level of seismic hazard as that considered in the design. From the results obtained, the average ductility demand of the elements is determined. Capacity and demand ductility values are compared. Results obtained in both analyzes are compared to verify if the elements can develop the proposed level of ductility. The obtained results are used to define design recommendations for the ductility capacity or seismic behavior factor of piers and columns of urban bridges.
