Study And Practice On The Cantilever Construction Control Technology Of (48+88+48) M For DaXi River Continuous Beam Bridge

With the continuous development of Chinese transport industry,prestressed concrete continuous beam bridge has been widely used,especially the emergence of cantilever pouring construction technology is to promote the rapid development of the continuous beam bridges.During the construction,the internal force and deflection of the continuous beam-bridge structure will change as the growth of the cantilever segments and the conversion of the system,And the difference of conversion order of structural system also affects internal forces and deflections of the structure.So for long-span continuous girder bridge,the demand of the construction control is higher and higher,the difficulty of the construction control is becoming more and more big.Firstly,based on summarizing and studying the applicability of various construction control technologies at home and abroad,this paper combines the characteristics of Daxi River Bridge(48+88+48)m continuous beam to formulate the construction control plan for this continuous beam.Secondly taking the continuous beam as the research object,the finite element model was established with the help of the bridge engineering software MIDAS/Civil 2015,and the whole process of the bridge construction was simulated and analyzed.Thirdly,the zero-section cast-in-place support and temporary consolidation of main girder were analyzed and checked,and it ensured the safety of temporary structure.Then,through the bridge model,the influence of structural linearity of the Daxi River Bridge by six control parameters such as concrete bulk density,concrete elastic modulu,main pier support settlement,prestress loss,concrete shrinkage and creep and temperature effect is analyzed,and the mutative rules of these control factors during the construction process are found out.Finally,according to the construction control plan,the elevation measuring points and buried stress sensors are arranged,the deflection and stress of the beam body was measured during the various construction stage.The measured values and the theoretical values were compared and analyzed.The adjustment quantity for each construction phase that concluded was used to guide the construction.To ensure the bridge structure in the construction process have an safe and smooth progress.Through this bridge construction control,its linear shape and stress state of main girder were in fair agreement with the designed values.The bridge construction control method has received the good effect.