Research On Segmental Precast Construction Control Of Railway Continuous Beam

In this paper,the stress in the position of seams is analyzed separately for the construction process of gluing and tensioning by using the finite element software named Midas/Civil based on the railway prestressed concrete continuous beam with the construction method of assembling precast segments.For the gluing process,the influence of different factors is firstly analyzed on the stress between the joint cross-section from three aspects: the position of the crane load,the real rigidity of the bridge machine and the reduction of the force in boom and it is concluded that the reduction caused by the conversion process of the hanging system is the main reason for the tensile stress.During the tensioning procedure,the influence caused by the stiffness of the bridge machine on the tensile stress and the boom force is discussed separately based on the actual value,the theoretical value and the infinity which shows that the stiffness is so large to bring the tensile stress when the bridge is designed.Therefore,the principle of force method is used to explain the causes of above phenomenon in theory.According to the position where the tensile stress may occur in the process of construction,four measures,increasing the number of steel bars on the surface of segments,strengthening the force in boom again,adjusting the tensioning order and removing the boom in batches,are respectively taken to prevent the tensile stress.Then the stress sensors are installed to monitor these sections and the results show that the data measured with the sensors are in good agreement with the theoretical value.So it can better reflect the stress of the beam and provide a reference for a similar bridge construction in the future.