Numerical Simulation of Vertical Prestress Loss of Prestressed Concrete Box Girder Bridge Based on Improved Genetic Algorithm

Abstract

In the concrete box girder bridge, the concrete is a brittle material, with low ultimate tensile strength and small ultimate tensile deformation. Because the box girder itself is a statically indeterminate structure, the concrete in the tensile zone is very prone to crack due to the load during construction and use. In this paper, the vertical prestress loss of prestressed concrete box girder bridge based on improved genetic algorithm is studied. The research shows that the stress generated by the additional bending moment at the center of the prestressed reinforcement reaches the ultimate axial compressive stress of 0.5%–3.4%, of which the vertical prestress of 3M near the midspan reaches 3.4%; The fixed end reaches 1.3%–8%, of which the vertical prestress of 3M near the middle of the span reaches 8%. When the vertical tendons are tensioned in batches by improved genetic algorithm, the influence range of the vertical prestressed tendons under the condition of different web height thickness ratio and the influence of the change of the height thickness ratio on the loss rate of the tendons are obtained. Using prestressed concrete structure through improved genetic algorithm is more durable in practice. Reinforced concrete has been subjected to large stress, which is equivalent to a strength test. To some extent, its safety is more worthy of affirmation.