Topology Optimization of Continuous Precast Prestressed Concrete Bridge Girders Using Shape Memory Alloys

Abstract

Despite the growing interest in the concept of topology optimization, its acceptance in civil structures, especially in prestressed concrete structures, is still faced with practical obstacles primarily due to the geometric complexities of optimized structures. Quite often, complex concrete topology yields a complex distribution of tensile zones, which are hard to be effectively prestressed with continuous steel reinforcement. Shape memory alloys (SMAs), with their ability to apply localized prestressing force only at target tensile regions, can offer solutions to the issues facing conventional prestressing steel reinforcement in topology-optimized concrete structures. This paper investigates the topology optimization of prestressed concrete bridge girders using locally prestressed SMAs. A prototype continuous concrete bridge is selected to be optimized under the AASHTO loading conditions. To prove the feasibility of the optimized design, a detailed 3D finite element analysis is performed. The performance of the optimized girder is compared with that of two commonly used conventional designs. The results show that the optimized design can effectively satisfy the AASHTO limit state with less material than the conventional cases.