A theoretical stress-strain model for confined concrete is developed to account for the effects of transverse reinforcement, including spiral, circular, or rectangular hoops, and their influence on the strength and ductility of concrete under uniaxial compression. The model uses a single equation to describe the stress-strain relationship and incorporates the effects of cyclic loading and strain rate. An effective lateral confining stress is defined based on the configuration of transverse and longitudinal reinforcement. The model predicts the longitudinal compressive strain corresponding to the first fracture of transverse reinforcement by equating the strain energy capacity of the transverse reinforcement to the strain energy stored in the concrete due to confinement. The model is applicable to both circular and rectangular sections and considers various types of confinement, including supplementary cross ties. The model includes a unified approach for both static and dynamic loading, and it accounts for the effects of strain rate on the stress-strain behavior of concrete. The model is validated against experimental data and is used to predict the flexural strength and ductility of reinforced concrete columns. The model also incorporates dynamic magnification factors to account for the effects of strain rate on concrete strength and stiffness. The ultimate concrete compressive strain is determined based on the energy balance approach, considering the work done on the concrete and longitudinal steel. The model is useful for seismic design and provides a basis for understanding the behavior of confined concrete under various loading conditions.A theoretical stress-strain model for confined concrete is developed to account for the effects of transverse reinforcement, including spiral, circular, or rectangular hoops, and their influence on the strength and ductility of concrete under uniaxial compression. The model uses a single equation to describe the stress-strain relationship and incorporates the effects of cyclic loading and strain rate. An effective lateral confining stress is defined based on the configuration of transverse and longitudinal reinforcement. The model predicts the longitudinal compressive strain corresponding to the first fracture of transverse reinforcement by equating the strain energy capacity of the transverse reinforcement to the strain energy stored in the concrete due to confinement. The model is applicable to both circular and rectangular sections and considers various types of confinement, including supplementary cross ties. The model includes a unified approach for both static and dynamic loading, and it accounts for the effects of strain rate on the stress-strain behavior of concrete. The model is validated against experimental data and is used to predict the flexural strength and ductility of reinforced concrete columns. The model also incorporates dynamic magnification factors to account for the effects of strain rate on concrete strength and stiffness. The ultimate concrete compressive strain is determined based on the energy balance approach, considering the work done on the concrete and longitudinal steel. The model is useful for seismic design and provides a basis for understanding the behavior of confined concrete under various loading conditions.