Analysis and design of large-span post-tensioned bonded prestressed concrete frame with transfer structure

Abstract

The roof of a swimming pool is supported by a 33.6 m-span post-tensioned bonded prestressed concrete frame, in which the presence of a heavy upper transfer structure and superimposed filling loads significantly complicates the structural behavior. This study presents a comprehensive investigation of such structural systems based on a practical engineering project. A refined analytical framework is developed to evaluate the flexural capacity, stiffness, deflection, and crack width of prestressed concrete frame beams, with particular consideration of prestress effects and secondary internal forces induced by the transfer structure. In addition, a performance-oriented design approach incorporating ductility requirements and vertical seismic effects is proposed. A three-dimensional global analysis is adopted to capture the interaction between structural components and to improve the accuracy of dynamic response evaluation. The results indicate that the presence of the upper transfer structure significantly affects internal force redistribution, and the induced secondary internal forces must be carefully considered in design. The proposed system demonstrates favorable structural performance in terms of load-carrying capacity, ductility, and seismic behavior under heavy loading conditions. Compared with conventional design approaches, this study highlights the importance of considering the coupled effects of prestressing and transfer systems, and provides practical design recommendations, including reinforcement configurations and construction procedures. The findings offer useful guidance for the analysis and design of similar long-span prestressed concrete structures with transfer systems.