Abstract:To improve the seismic performance of fabricated steel beams and columns, a flexible mechanical model with variable cross-section was designed to evaluate the prestress of the cross-section seismic performance. In this method, ultimate bearing capacity constraints were used for seismic analysis and flexural stiffness softening coefficient was introduced to correct the error and then the load moment of the steel beam and column was obtained. Through stress assessment and structural decoupling design, seismic evaluation of steel beam and column was realized. The seismic performance analysis function having steel strength, ductility index, and seismic vulnerability of steel frame as constraint parameters was constructed, and the prediction method of initial prestressing for thin waist cracking of prefabricated steel structure was established to realize the accurate evaluation of prestress of beam and column in prefabricated steel structure. The test results showed that the proposed model can accurately calculate the stress-strain relation, yield strength, and ultimate bearing capacity of beam and column in prefabricated steel structure, thereby improving the seismic performance of beam and column in prefabricated steel structure.