Energy-based approach to predict thermal cracking characteristics of a massive RC member subjected to external restraint from its bottom

Thermal cracking is a crucial problem in massive reinforced concrete structures, particularly in terms of durability. Although several standards and numerical studies have been used to evaluate thermal crack width and number of cracks, quantitative evaluation remains challenging. This paper proposes a robust prediction model that can be used to theoretically evaluate thermal cracks using a simplified approach. A parametric study based on a rigid-body-spring model (RBSM) was conducted to clarify the factors affecting the thermal cracking characteristics of massive concrete members. The proposed energy-based prediction model based on the information from the parametric study reasonably evaluates the thermal cracks observed in an existing experiment. The crack width distribution in the cracked section was also investigated to define the equations for the gradient of the thermal crack width, which is important for evaluating the crack width on the surface with respect to durability.

Automated summary

Thermal cracking in reinforced concrete structures poses a significant durability challenge. Quantitative evaluation of thermal crack width and number of cracks remains challenging despite existing standards and numerical studies. This paper presents a robust prediction model based on a simplified approach to evaluate thermal cracks theoretically. A parametric study using a rigid-body-spring model (RBSM) determines the factors influencing thermal cracking characteristics in massive concrete members. The proposed energy-based prediction model, informed by the parametric study, accurately evaluates thermal cracks observed in an experimental setting. Additionally, the study investigates crack width distribution and establishes equations for the crack width gradient, which is crucial for assessing surface crack width and durability.