Analysis and Control of the Reasonable Alignment of Prefabricated Small Box Girders in Complex Environments

Abstract The natural environment has a significant impact on the structural performance of prestressed concrete small box girders during the manufacturing and installation stages. It was focused on the Longdong region of Gansu Province in China, where the climate is characterized by distinct seasonal variations in temperature and humidity, long hours of sunlight, and significant diurnal temperature differences. The study investigates the alignment changes of prefabricated small box girders with a span of 30 meters. Relative humidity and loading age are considered as the primary control variables, and the deformation of the structure under various conditions is analyzed. The results indicate that relative humidity plays a decisive role in alignment control. For regions with large variations in temperature and humidity, it is recommended to use a control standard of 10mm during the beam storage stage, and to control alignment by increasing relative humidity and appropriately extending the loading age.