Study On Construction Control And Temperature Effect Of The Continuous Rigid Frame Bridge On The Tibet Plateau

With the rapid development of bridge construction technology and the improvementof prestressed,the span of bridge is also increasing,and the structure of the bridge is alsobecoming more complex.In order to making the linear and the stress of bridge meet therequirements, keeping the bridge construction process safety, so the construction controltechnology of long span bridges emerged as the times require it,At the same time,accompanied by the deepening study of computation theory,temperature effects,creep andshrinkage of concrete, the construction control technology of long span bridges are increasinghighly. With the application of continuous rigid frame bridge is more and more widely, thelong span prestressed concrete continuous rigid frame bridge has been one of the main bridgestructure in bridge construction, and the long-span continuous rigid frame bridge constructioncontrol technology becomes more and more important.In this thesis, take the3rd SuperBridge of Brahmaputra as the project background, using Midas-Civil as analysis software toanalysis construction process of the bridge which would get deflection and internal force ofbridge at different construction stages, to provide reference data for bridge monitorin g inconstruction process, which can guide the construction, to ensure that the the bridge closure.In each stage of construction,according to the monitoring program which has beenestablished strictly, monitoring the force and linear state of the structure in different stages ofconstruction,being compare the measured values with the the oretical value, which wouldidentification, adjustment and prediction the error that would make actual state of bridgestructure is close to the ideal state.Because of the long-span prestressed concrete box girder bridge has many advantages soit has been widely used, but the crack of prestressed concrete box emerged is inevitable.Because of the temperature has large effect on the bridge stress, especially thefast temperature variation and low temperature conditions in the Tibet area. At the same timein the winter construction, curing temperature difference inside and outside the box body islarge, in this situation tensile stress would produce,so it is necessary to control thetemperature difference between inside and outside reasonable and the tensile stressreasonable which can ensure prestressed concrete without cracking durring curing periodbefore tensioned concrete.This paper analyses the effect of temperature on the long-spancontinuous bridge girder stress, put the3rd Super Bridge of Brahmaputra as anexample,using Midas-Civil software,which can calculation the maximum stress of box section oflong-span bridge and analysis the position which is most likely to produce cracks and take thenecessary measures. Using Midas-FEA software analysis stress of single relativelyclosed block,during winter construction,in which time the temperature inside of the box is higher than the outside,to provide the necessary reference for curing temperature setting whenconstruction in winter.