Numerical simulation and control of early‐age cracking in a concrete cap beam: Considering high‐strength concrete and constraint of formwork

Abstract Bridge cap beams, which are crucial components that connect girders and piers, are also prone to early‐age cracking despite the relatively small volume. This paper presents a thermo‐mechanical simulation of the construction process of a cap beam in a specific engineering project, analyzing the causes of early cracking. Unlike previous studies, this research places emphasis on the thermal parameters of high‐strength concrete (HSC) and the constraining effects of formwork. The study successfully reproduced the temperature, stress, and crack development during the cap beam's casting process. It was found that the use of HSC, combined with the accelerated construction schedule requiring a single‐pour method, led to concentrated heat generation during the early hydration reaction, resulting in cracking failure. Finally, the cracking was successfully avoided by implementing the embedded cooling pipes technique. The simulation method and preventive measures proposed in this paper regarding the early‐age cracking behavior of concrete are recommended for practical applications.