Experimental and theoretical studies on lateral behavior of prefabricated composite concrete-filled steel tubes truss column

Enhancing the lateral force resistance of residential structures through innovative prefabricated designs is crucial for improving structural resilience and safety. This study presents an innovative design for prefabricated concrete-filled steel tube (CFT) column trusses with V-shaped or Z-shaped configurations to enhance the lateral displacement and ductility of residential buildings under lateral forces. The CFT-column truss is a prefabricated system featuring two square CFT columns connected to H-section beams using fish plates. Additionally, the beams and columns are linked to a web truss component made of double-angle sections. To assess their failure patterns and characteristic capacities, two large-scale specimens were subjected to lateral monotonic loads. The test results indicated that both V-shaped and Z-shaped trusses exhibited exceptional performance. The V-shaped trusses demonstrated significant improvements in yield stiffness and ductility, increasing by approximately 22 % and 31 %, respectively. However, the yield and peak bearing capacities of these trusses were reduced by about 10 % and 6.75 %, respectively. Furthermore, a theoretical model was developed based on the observed test failure modes and verified through finite element (FE) analyses. The predictive results of the theoretical model were compared to a group of FE models, demonstrating their suitability for accurately estimating bearing capacities and yield stiffness with a high level of agreement.