Common causes deflection under the bridge crane girder four reasons

Causing general  overhead bridge crane  girder deflection under four reasons
    1, high temperature working environment. High temperature environment of the crane girders have a greater impact. This is because the use of the thermal processing plant overhead crane, the main beam in a high temperature bake long state, thereby reducing the yield limit of the metal material and a temperature stress, temperature stress and other stresses on the one hand superimposed may exceed the material yield limit; partly because the upper and lower plate girder uneven heating plate temperature is much higher than under the cover, lower cover stretch more, finally leading to the main beam under torsion.
    2, and the irrational use of overload. Overload, overtime, and is caused by irrational use of bridge crane girder deflection under another important reason. Part of a single piece of hanging objects weighing more than the bridge crane's rated load, resulting in a long period of bridge crane overload state; while some workshop for the time duration, race against time, to take "break people prodigiously machine" approach, working-level superbridge crane used to make bridge crane long-term state of fatigue. These two unscientific methods will make the main beam in the local stress even more than the yield limit, resulting in deformation of the main beam under torsion. What is more, individual workers use bridge crane haul heavy loads, which is caused by the main beam under torsion of the important reasons.
    3, bridge cranes unreasonable storage, lifting, installation affected. As the Department grew bridge crane bridge structure, greater flexibility, unreasonable storage, lifting and installation will cause the bridge deformation. Some new bridge cranes for various reasons not timely installation, the installation before being put in everywhere one, did not take measures to prevent deformation of the bridge; while some new bridge crane was being lifted, the installation process, no basis bridge gravity and the force Designed lifting program, which results due to brutal lifting bridge deformation. This is caused by the bridge crane girder deflection under one of the reasons.
    4, the impact of the design and manufacturing process. bridge crane design and manufacture of deficiencies under the main beam deflection is caused by one of the reasons. First, because the bridge crane  design and manufacturing quality not up to standard requirements, the main beam stiffness has not been fully guaranteed, when used under the main beam generated torsion; second is due to force assembled in the manufacturing process resulting in different directions tensile, compressive stress and welding residual stress caused while in use, these stresses gradual homogenization or even disappear, so that the main beam permanent deformation, can also cause the main beam under torsion.