Restraint Crack Width – Analytical Model for Reinforced and Hybrid Reinforced Concrete

Kapitel i bok, 2025

In the present work, an examination of the different approaches used to address restraint cracking in current design codes as well as a review of available state-of-the-art models for restraint cracking was performed. The cracking behaviour of tie-elements with hybrid reinforcement was experimentally investigated as a function of the fibre reinforced concrete properties, namely bond behaviour and residual tensile strength, which were assessed for a range of fibre dosages. An existing restraint cracking model based on a semi-empirical analytical relationship between the crack width and the stress at the reinforcement was further developed to include the effect of fibre reinforcement and was validated against experimental results, both from this study and reported in the literature. The proposed model agrees well with the average results from the experimental tests on RC tie elements as well as with other analytical formulations. The present restraint cracking model was able to accurately predict the number of cracks formed in slabs experimentally tested by others. Moreover, a reasonable agreement was found between the analytical predictions and the experimental results for the average crack width and the maximum stress at the reinforcement, demonstrating the predictive capabilities of the model.