To simplify the calculation method of bending capacity for preflexed composite beams in current standard

the calculation method of plastic bending capacity was deduced based on the theory of plasticity

and a simplified calculation method of bending capacity for preflexed composite beams was put forward from the aspect of security. The bending capacity of seven experimental beams was calculated by the simplified calculation method

the elastoplastic calculation method in the standard

and a deduced calculation plastic method. Nonlinear finite element analysis was carried out on the preflex beams by the general finite element analysis software Abaqus

and the calculated results were compared with measured results to verify the accuracy of the proposed calculation method. Results show that the differences between the results calculated by the proposed method and those by the elastoplastic method were less than 2% for the seven experimental beams. The calculated values were slightly smaller than the measured and simulated values and showed good agreement

which could satisfy the requirements of calculation accuracy and safety in practical projects. The proposed simplified calculation method of bending capacity was simpler than the method in existing standards and the plastic method

which could be used in the calculation of cross-section bending capacity for preflex beam bridges. Based on the research results

an example of preflex simply supported beam bridge calculated by the proposed method was given

which could provide reference for practical projects.