预应力混凝土安全壳结构承载能力评估方法研究OA

For prestressed concrete containment under long-term service conditions,the B3 model is used to describe the shrinkage and creep of concrete,and the FIB-2010 model is used to simulate the relaxation of steel strands.The rate-type constitutive equation is derived,and a time-step iterative algorithm is developed to consider the coupling effect of the two.Material constitutive is realized through the UMAT subroutine on the ABAQUS platform;A finite element model is established based on the containment of a nuclear power plant,and a containment performance analysis model under internal pressure is established using dynamic methods.The B3 model parameters were identified and corrected using measured prestress data to verify the reliability of the model.The verification of the coupled algorithm shows that the direct superposition of shrinkage,creep and relaxation losses is conservative,with a relative error of 7.3%.After parameter correction,the model agrees well with the measured prestress loss curve of the steel tendon.The service performance of the containment under internal pressure after 60 years is simulated.This study establishes a prestress loss assessment method that considers the coupling of multiple factors,improves the prediction accuracy of containment bearing capacity,and provides a reliable basis for long-term performance assessment and life extension decisions of supporting nuclear power structures.