Break the line first;  tension beams;  Reaction beams;  steering gear;  Prestress

Through the construction monitoring of the 35 m folded line first tension beam, the influence of the deformation of the tension beam and the reaction beam, the frictional resistance of the steering gear on the prestress loss, and the prestress loss under other conditions were analyzed. The results show that the calculation of prestress loss of prestressed box girder is more accurate than that of post-tensioned prestress method, which avoids engineering diseases caused by unreliable prestress value, and the total prestress loss value of prestressed linear box girder is smaller than that of post-tensioned method, which ensures the tensile stress. The analysis shows that the stress loss caused by shrinkage and creep of concrete in the tensile area and compression zone has the largest proportion of the total prestress loss of the pre-tensioned linear box girder, so it is an effective measure to control the total prestress loss of the pre-tensioned linear box girder by reducing the shrinkage and creep of concrete.