Q. Lifting of girders?
Lifting of girders : For greasing the bearings girders are required to be lifted. But the gap between the bottom flange of plate girders and the bed block generally varies from 100 mm to 150 mm. The standard jacks normally available have a closed height of at least 300 mm. These jacks, therefore, can't be used for lifting the girders without making special jacking arrangements.
Following jacking arrangement can be adopted for different types of girders:
1. For plate girders upto 6.1 m span, jacks can be directly applied below end sleeper ensuring firm hook bolt connection, since load to be lifted is about 4 to 5 ton only.
2. Jacking arrangement for span 9.15 m plate girder requires provision of a hard wood beam below inner top flange.
3. Jacking arrangement for span 12.2, 18.3, 24.4 and 30.5 m plate girder requires provision of a steel beam.