| Prestressed simply supported beam bridge has been widely used in highway and urban bridge engineering in China.However,the existing prestressed simply supported beams have various problems in operation.Due to some adverse loads,the structure may not work normally.Therefore,it is necessary to further study the prestressed concrete simply supported beam structure.In the research of concrete structure,model test is an effective research method.Since the birth of the model test,the relevant model similarity theory has made great progress,but at present,the research on the similarity model of prestressed reinforced concrete structure has the problem that the model does not consider the reinforcement,resulting in the dissimilarity between the model and the model,and there are also the problems that the conventional concrete materials are not suitable for model making,which makes the design more difficult.Therefore,this paper studies the similar model of prestressed simply supported beam as follows:(1)For the prestressed simply supported beam,the equation analysis method is used to combine the similarity theorem with the effective moment formula of prestressed reinforced concrete beam and the section bending stiffness formula respectively.The moment similarity criterion and stiffness similarity criterion are proposed in the design of prestressed simply supported beam model.(2)For the standard prestressed simply supported T-Beams with a span of 25 m,the bending moment similarity criterion model and stiffness similarity criterion model are designed with various similar proportions respectively.The numerical models of the prototype and each similar model are established by using ANSYS finite element analysis software.The prototype similar working conditions are applied to the model,and the results of characteristic points are collected for analysis and comparison to verify the accuracy of the similarity criterion and analyze the influence of the change of similar proportion on the results.(3)Similar model design is carried out for the two prestressed simply supported girder bridges that have completed the actual bridge test.The beam experimental results are compared and analyzed to test the correctness of the design method of the similarity criterion of the two models.(4)For the 8m span prestressed concrete beam with simple reinforcement,two similar models are designed at the scale of 1:8.The model of similar model prototype is established by using ANSYS software.Two similar model beams are made respectively by using self compacting mortar and scored steel wire as model materials.The results of each measurement point are compared to evaluate the accuracy of the two similar models.After numerical simulation verification,the difference between the results of similar models with different similarity ratios is not large,and accurately restore the mechanical properties of the prototype.The software calculation results and model test results show that the deflection results and reinforcement deformation of the model with similar stiffness are less than 20% compared with the prototype,and the maximum difference of stress results is49.54%.The errors of concrete and steel stress results of similar bending moment models are both within 20%,but the maximum difference in deformation results is more than 50%.Therefore,in the similar model test,similar models can be designed according to the two criteria,and the corresponding deformation and stress characteristics can be inverted respectively,so that the similar model test results can simulate the prototype more accurately. |
