Influence of Fracture and Delayed Effects on Steel-Concrete Composite Structures

Abstract

This work investigates the fracture behavior of Preflex beams submitted to time dependent effects and long term loadings. However, it is necessary to consider delayed effects such as shrinkage and creep on these structures because their influence is not negligible. The different materials used in mixed construction are presented. The flowchart applied to compute creep and relaxation effects versus the time is also described. It is interesting to note that the analytical results obtained for a Preflex beam are very similar to those obtained using finite element modelling on the LUSAS software. It is also observable that the cracking of the concrete that encases the lower fibre, due to creep, causes an increase of stresses in the steel profile that can lead to the break of the beam. The use of reinforcement on the preflex beam decrease the crack opening after 100 years loadings.