Conceptual design and analysis on an innovative hybrid CFST latticed bridge pier with an RC lacing system

To expedite the application of concrete-filled steel tubular (CFST) bridge piers , particularly in mountainous regions , this study introduces an innovative hybrid CFST latticed bridge pier with a reinforced concrete (RC) lacing system, consisting of four CFST columns, prestressed RC braces, and RC tie beams. All components could be precast and assembled via prefabricated connections. This hybrid CFST latticed pier offers several advantages, including enhanced structural performance, convenient construction, reduced self-weight, and environmental sustainability. A three-span continuous rigid frame bridge with proposed CFST latticed piers is designed based on a benchmark bridge with RC double-wall piers. The mechanical performance of the prefabricated connections in the designed CFST pier, those employed to connect braces and columns, is investigated in detail through numerical analysis, validating the effectiveness of this novel connection. Refined finite element models of both the bridges with RC double-wall and CFST latticed piers are developed to compare and assess their dynamic responses through performing nonlinear dynamic analyses of full bridges. The results indicate that the CFST latticed pier exhibits lower pier top displacements compared to conventional RC wall piers, while the CFST columns maintain elastic behavior, and the prefabricated connections demonstrate reliable performance under severe earthquake conditions.