Reaserch On The Long-term Deflection Of Long-span Pre-stressed Continuous Rigid Frame Bridges

Since entering the19th century, with the development of pre-stressed system, thelong-span pre-stressed continuous rigid frame bridges have been growing up rapidly with itsunique predominance of handy construction, economical cost, reasonable interal force andcomfortable traveling. However, excessive defleetion in mid-span is a widespread problem ofthe rigid frame bridges, and generally did not establish appropriate health monitoring systemto assess the real-time status of bridges in operating condition,leading to some kind of bridgesevere disease and even sudden collapse, causing serious economic losses and even people’slives and property crisis, so the operating condition of the bridge deflection real-timemonitoring and control of long-term defleetion are of great significance.In this paper,firstly the author will take the project of the Pingtan Strait Bridge as thebackground,use finite element software Midas for analogy calculation,and compare the effectsof the prestress,shringkage and creep model,box girder rigidity,on the midspan deflection oflong-span pre-stressed continuous rigid frame bridges.Secondly, this paper describes the system Pingtan Strait Bridge health monitoringsystem, including its works, the hardware configuration, installation of the monitoringsystems, and collect the Pingtan Strait Bridge up to3years’ real-time monitoring data.Byanalyzing the Pingtan Strait Bridge mid-span actual monitoring deflection data, furtheranalysis of variation of continuous rigid frame bridge the long-term deflection, provide thebasis for such bridge-type construction, design, maintenance, etc.Finally, in order to take the initiative activity to control the long-term deflection of mainbeam,zero bending moment theory has been introduced.Using top slab prestress to controllong-term deflection of mid-span is studied. In this paper top slab tendons areredesigned onthe basis of zero bending moment theory, the displacement are compared with originaldesign,verifythe feasibility that zero bending moment theory to control long-span pre-stressedcontinuous rigid frame bridge span deflection.