Study On One-Closure Scheme For The Long Span Continuous Rigid Frame Bridge

Recently,based on the economic development of our country,many long spanprestress-ed concrete continuous rigid frame bridges are built. The long span PC continuousrigid bridge is good characteristic of structure stress performance, big stiffness, less expansionjoints, smooth and comfortable driving, less maintenance for the later period, and mature ofconstruction methods, so this bridge is widely applied in our country.The closure plan selection is key link in the long-span prestressed concrete continuousrigid frame design and construction.Based on four continous rigid frame bridges in the paper,Applying the soft of MIDAS/Civil, two different closing scheme optimization and theprejacking force were carried out in this article. Some work and achievements were followed:(1)The internal force and defection were calculated and compared in the four differentspan of the long span PC continuous rigid bridge.This thesis compared and analyzed the system temperature effect between one-closurescheme and successive closure scheme.The analysis results showed the system temperatureeffect had a complex effection toward the two different closure plans of the differentmulti-span continuous rigid bridge,the more the number of the span was,the the greater theimpact was.(3)This thesis compared and analyzed concrete shrinkage and creep effectsbetween one-closure and one-by-one closure. The analysis results showed that one-closurescheme was smaller than successive-closure, the shrinkage and creep effect difference of twoclosures would be more significant.(4)Firstly, the necessity of measure of prejacking was studied in this thesis.Then theinfluence matrix method was proposed to optimize the prejacking force, by means of thesoftware of MATLAB, and then a prejacking force scheme that was able to make the stress ofstructure during the final bridge stages approach rationable was calculated by combining theinfluence matrix method and bisection method.The closure of continual rigid frame bridge is one of the extremely important workingprocedures in this bridge construction.This thesis proposed two different closing schemes onthe basis of their original design closing scheme, compared the stress and deflection ofdifferent construction closing order in service stages,under the system temperature effect and shrinkage and creep effects,and then concluded and optimized a prejacking force scheme bycombining the influence matrix method,the research results could provide reference for thesimilar multi-span PC continual rigid frame bridge closure.