Research And Practice Of Construction Control On (42.85+72+72+75+42.85)m Continuous Beam Bridge

In recent years,bridge engineering in China’s highways and high-speed railways has seen a booming development.In the construction of continuous beam bridges in China,construction control determines the overall construction quality of the project.Multi-span continuous beams need to undergo several system transitions during construction,and therefore require more precise construction control to ensure that the various construction stages from the start of construction to the completion of the bridge meet the design standards and specification requirements.In this thesis,a finite element simulation model of the main beam was established using Midas Civil 2020,and the theoretical values of deflection and stress were analysed and compared with the measured elevation and pre-built sensor stress data on site.According to the pier and beam consolidation design of this continuous beam,the temporary consolidation was examined.Three methods were used to simulate the temporary consolidation and permanent support,and the deflection and stresses in the simulation results were compared and analysed.It is concluded that the method which takes into account the longitudinal position of the temporary tie,the actual height of the permanent support and the pier is more reasonable and can improve the accuracy of construction control.Continuous beam bridges are usually designed as symmetrical structures in order to balance the loads symmetrically on both sides of the pier top.However,due to the topography of the site,the upper main beam was designed as an asymmetrical structure.The unbalanced internal forces resulting from the asymmetrical structure may have an impact on the construction control and operational safety of the bridge structure.Two methods were used to simulate the construction of the cantilever in the asymmetric section,and to summarise the changes in deflection and stress in the simulation results.The method of removing temporary consolidation at a later stage was found to be more effective than the method of applying temporary compression weights,reducing the unbalanced bending moments during construction,preventing tension in the side bearings and reducing the difficulty of construction control.Finally,a simulation model was built for the bridge with four different sequences of closure,and the simulation results were compared and analysed for deflection and stress.It is found that the side span-mid span-sub-mid span sequence is beneficial to the control of the closure accuracy.