Numerical and hybrid analysis of a curved bridge and methods of numerical model calibration

Reinforced concrete (RC) bridge piers are subjected to combined loading conditions resulting from complex earthquake ground motions coupled with irregular geometry and asymmetry of the bridge structure. Furthermore, the influence of the assumptions and simplifications made in modeling irregular and curved bridges on the reliability of their resulting response data is still not fully known. For that purpose, in this paper a hybrid simulation test is conducted on a curved four-span bridge. This test accounts for the three-dimensional (3D) system-level interaction between the three experimental piers in two testing facilities with the numerical models of the deck, restraints and abutments. Prior to the hybrid simulation, a detailed numerical finite element, fiber-based model of the whole bridge system is established. The analytical predictions of this model are then used for comparison with the hybrid simulation test results. Discrepancies between the numerical and experimental results of the bridge piers response are highlighted and deficiencies in the numerical model assumptions are discussed. A rigorous numerical model calibration procedure is then followed to adjust for the initial modeling assumptions and improve the bridge model overall response. This study has proven that some modeling assumptions that are widely used in seismic analysis of bridge structures are unrealistic and therefore may lead to inaccurate results.