Why does the bridge frame deform?
The deformation of metal structure is a normal question, especially the main girder of hoisting mahcinery which as the main bearing parts, in order to avoid deforming, ZZHZ give some advice of gantry crane to us:
2. The reason of deformation
2.1 The reason of reducing of camber
1) The influence of internal stress of structure
2) Unreasonable using and overload
3) The influence of high temperature
4) The influence of design and technology
5) Unreasonable lifting, storing and assembling
6) Unreasonable repairing
2.2 The reason of side-bend
1) Production of horizontal curvature when using
2) The precast side-bend of requirement of technology
3) Production of horizontal curvature because of the modification of structure
4) The main girder bends inside because of the horizontal inertia force
2.3 The wave deformation of web of main girder
When the web is assembled, the steel plate is not flat, so it produces the wave deformation because of the internal stress.
2.4 The deformation of end girder
1) in order to increase the connecting rigid of main girder and end girder , sometimes the user welds a steel plate on the head of main girder and end girder, so it makes the end girder bend outside.
2) The biting rail of crane
3) The deformation of middle girder
2.5 The deformation of oversize of diagonal
Horizontal direction of the connection of main girder and end girder deforms.
3. The repair of bridge frame: prestressed tension method of steel bar, prestressed tension method of steel rope and flame correcting method
