Long-span Continuous Rigid Frame Bridge Across The Middle And Lower Torsion Problem Research And Countermeasure Analysis

In recent years, the prestressed concrete continuous rigid frame bridge with its simple construction operation, reasonable force, economical cost and other advantages has been widely used. But because the continuous rigid frame bridge in our country starts late, the design theory is not perfect, the construction technology level is not advanced enough, in recent years, the bridge operation condition of the inspection found that there are a lot of defects. Large span prestressed concrete continuous rigid frame bridge are the main diseases is the main span and long term deflection and the box girder cracking, these diseases on driving comfort caused serious influence, threat bridge normal use. Therefore, the research on how to control continuous rigid frame bridge main span of long term deflection, has very important practical significance.First, access to data and research on continuous rigid frame bridge design, construction, operation, respectively from the concrete shrinkage and creep, prestress loss, live load overload and box girder cracking caused by the stiffness loss research of long span prestressed concrete continuous rigid frame bridge has to take place mid span deflection causes.Second, the selection of the main span is 104m,130m,150m three continuous rigid frame bridge as the research object, the finite element model of the bridge is established by Midas/civil, calculation and analysis of the longitudinal prestressing loss, shrinkage and creep model, box beam stiffness loss, concrete loading age and live load surcharge and other factors on the different span continuous rigid frame bridge midspan deflection sensitivity.Found one mainspan 102.25m of the continuous rigid frame bridge in Yunnan province (Longteng bridge) adopted the innovation design, has been operating for three years, not only in the bridge across no downwarping indeed improve the 15 mm or so. Analyzing the design scheme of the bridge, using Midas/civil software whole bridge finite element model is established, with the same span, and the traditional design scheme design of continuous rigid frame bridge finite element model comparison and analysis of Longteng bridge design scheme and the traditional design scheme to the control of long span continuous rigid frame bridge across differences in long-term downwarping.Finally, the selection of construction in Yunnan province mainspan continuous rigid frame bridge is 130m and 150m, construct a finite element model with Midas/civil software. Will mainspan for 130m and 150m use Longteng long span continuous rigid frame bridge design scheme of design changes, comparing the two continuous rigid frame bridge in bridge structure difference before and after the design change, Longteng bridge design theoretically research on other span continuous rigid frame bridge can have the effect of long-term effective control across downwarping.