Research On State Evaluation Of Prefabricated Bridge Structure

The traditional method of using on-site concrete pouring technology for road and bridge construction is more and more difficult to meet the development needs of modern municipal road and bridge construction due to large noise pollution,long construction period and serious waste of resources,energy and manpower and material resources in the construction process.With the rapid development of China’s construction industry,technology based on standardization,assembly and informatization has become the preferred way for the construction of transportation facilities,providing more efficient and reliable services for bridge construction.The number of existing prefabricated bridges in China accounts for more than 70% of the total number of highway bridges,and the biggest feature of these prefabricated bridges compared with traditional bridges is modular,simple structure and clear force.The earliest prefabricated bridges were in operation for more than 20 years,during which critical components of the bridge were damaged and overall safety performance was reduced.China’s existing bridge inspection and assessment specifications are difficult to combine the characteristics of prefabricated bridge structures to achieve objective and accurate assessment when evaluating prefabricated bridges.Therefore,this paper studies the technical condition assessment method of prefabricated bridges.The main research contents are as follows:First of all,through the statistical analysis of the detection data of hollow slab bridge,small box girder bridge and prefabricated T girder bridge,the disease characteristics and frequency of vulnerable components of prefabricated bridges were studied,which provided data support for the evaluation method of typical components of prefabricated bridges.Second,a prefabricated bridge evaluation model consisting of six levels,including components,components,parts,bridge spans,evaluation units and whole bridges,was established.Through the combination of questionnaire survey and statistics,the weight values of each part and component of the prefabricated bridge were determined.Thirdly,By referring to the methods of treating component diseases in different norms,the disease assessment table of prefabricated bridges was established,which solved the problem that there were no unique disease detection indicators of prefabricated bridges in the current assessment standards.According to the degree of influence of disease on the structural safety of prefabricated bridges,a disease scale correction method was formulated,and the classification limit value of prefabricated bridges was proposed.Drawing on the principle of linear interpolation in the current specification,the disease scale conversion formula is proposed,which solves the problem of excessive deduction of points for different disease types.Fourth,taking the real bridge detection data as an example,the difference between the evaluation criteria and the proposed method on the bridge assessment results is analyzed.The reliability of the proposed method for the evaluation of prefabricated bridges is demonstrated.According to the research results of this paper,the "Technical Status Assessment Guide for Prefabricated Bridges" was compiled to provide a scientific basis for the revision of bridge assessment standards in the next step.