An efficient method for time-dependent analysis of composite beams

Abstract

Composite beams have found wide applications in buildings and bridges. As the time-dependent effects, including the ageing, creep and shrinkage of concrete, affect the interaction between concrete and steel, it is essential to account for them properly to ensure satisfactory service and safety. This paper presents an efficient method to investigate the time-dependent performance of composite beams. Firstly, the age-adjusted elasticity modulus to account for concrete creep and the shrinkage-adjusted elasticity modulus to account for concrete shrinkage and its interaction with creep are introduced. Then an effective single-step numerical method for time-dependent analysis is developed in conjunction with the finite element method. Results obtained for the time-dependent behaviour and long-term redistribution of stresses agree well with published results. Numerical results show that the interaction among concrete ageing, creep and shrinkage increases the long-term deformation and results in stress redistribution, particularly at the interface.