An Optimization on Closure Jacking Scheme for Multi-span Continuous Rigid Frame Bridge
In order to effectively reduce the longitudinal horizontal displacement and additional internal force on the top of each pier of multi-span continuous rigid frame bridge at later stage,the optimized scheme for sequential jacking from the middle to the side closure is put forward,and the corresponding calculation diagrams are given and the relevant theoretical calculation formulas are deduced.Simultaneously,according to the needs of theoretical calculation formula of jacking force,the theoretical calculation formula of bending moment of inertia of the main beam and pier with variable cross-section is derived.Taking a six-span continuous rigid bridge for an example and establishing a FEM,the theoretical calculation formula and the finite element model are used to calculate the jacking force of the optimized scheme and carry out comparative analysis to verify the effectiveness of the theoretical calculation formula of the jacking force belong to optimized scheme.Subsequently,the original jacking scheme from side to middle and the optimized jacking scheme from middle to side to verify the rationality of the optimized jacking scheme are compared.The result shows that(1)compared with the original scheme,the optimized scheme increases the number of jacking,but the value of each jacking force is substantially reduced compared with the original scheme,that effectively reducing the local stress level at the jacking position;(2)the deformation of each pier is better controlled with the optimized scheme,especially the pier far from the midpoint of the main beam,therefore,the optimized solution is more effective in improving the longitudinal horizontal displacement of the pier top and the bending moment at the bottom of pier;(3)the jacking force calculated with the theoretical calculation formula of the optimized scheme is larger than that with the FEM,but the difference is small in general,that meeting the requirements of the actual project;(4)the main impact of different jacking schemes is the deformation and internal force of the bridge piers,and the impact of jacking construction on the shrinkage and creep of the main girders and the alignment of the completed bridge is not significant.
bridge engineeringoptimization on jacking schemenumerical simulationcontinuous rigid frame bridgepier deformation
NETL
NSTL
万方数据
