Experimental Study on Reasonable Steam Curing Scheme of Prefabrication Box Girder

The assembly‐line production mode was adopted to meet the production demands of prefabricated box girders for the Haiyan line. The steam curing method was introduced to accelerate concrete strength development, allowing the prestressing tension requirements of the box girders to be met quickly. This approach significantly improves the production efficiency of the prefabrication assembly line. First, the steam curing technology used in this project was analyzed, and multiple steam curing schemes were proposed based on existing engineering experience. Second, a total of 71 box girders were tested using a multistage verification experimental method. In Stage I, the temperature variation and distribution are measured, and these results can also be applied in subsequent simulation calculations. Stages II–IV involved preliminary scheme formulation, scheme verification, and scheme reoptimization, respectively. During these stages, data on material performance were obtained from the test beams and from concrete blocks cured under the same conditions. Changes in camber values were also compared. The optimal steam curing scheme for box girders was determined by comparing and optimizing the results from multiple rounds of measurements. Finally, a simplified simulation method for optimizing curing scheme was proposed. This method can be updated in real‐time based on the measured concrete strength. The study demonstrated that the curing schemes with constant temperature of 45°C for 12 h and 50°C for 10 h are more recommended for the box girder with a beam height of 1.6 m. In addition, the proposed simplified simulation method can be applied to determine suitable curing schemes for these girders, effectively reducing the need for costly large‐scale beam testing.