Study And Application On Construction Control Theory Of Stress-free Status Methods For Long Span Cable-stayed Bridge

Long span bridge project is generally used phased installation method, Construction of bridge structure from the beginning to finished must go through a complicated multi-phase component of the installation and system conversion process. In order to ensure the security in the process of construction and meet the design requirements of finished states on internal forces and linear,Some corresponding measures must be take in process of bridge construction to monitor and control construction process. Since the existence of some factors affecting the structural internal forces,such as the errors of the installation weight and the size of section of the main beam,and some factors affecting the structural deformation,the effect of cable-stayed bridge construction control has a great uncertainty.Stress-free status methods start with the relationship between the construction process to the final state of structure to study, Envisaged removable all structure loads, including all the dead load, and dismantling cable-stayed bridge, all of the cable-stayed bridge modules are in a zero-stress state(At this point,the length and curvature of the unit called non-stress unit length or non-stress unit curvature, the length of cable called non-stress-cable-length).According to the original non-stress-length and non-stress-curvature of component units restore cable-stayed bridge, regardless of how structural units by the sequence of installation, the internal forces and linear of the restore structure will be consistent with the original structure.The non-stress-length and non-stress-curvature of structural component units not change with external loads, the non-stress-length and non-stress-curvature of beam or tower units be controlled and adjusted only when installation of the unit,the cable's non-stress-length change only when the cable in tension.Establishment the link of between the construction stage and the finished state according to the constants of structure component units in stress-free status,the uncertainty of cable-stayed construction control will be resolved, etcIn accordance with the basic principles of stress-free-status methods, Simulation analysis zhongxian changjiang bridge in construction stage for the construction phase by ansys FEM program, to verification of the superiority of stress-free status methods.