There is a crane girder of a built-up I-section with span 12 m simply supported on two brackets. After 15 years of operation of double girder overhead crane, the girder is currently deflected downwards up to 3 cm at some points while the allowable deflection is L/800 which is 1.5 cm. What is the best action for this girder?
You can strengthen the girder, either by welding steel plates to the web and flanges, or by using FRCP Sheets.
The deflection limits are guidance and depending upon the functional use we can modify. In the current uses the girder can be strengthened by additional plates on flange if the deflection are due to flexure and by web plates if due to shear. In any case there should not be any plastic deformation.
it depends on which cost less repairing or replacement , after 15 working years i suggest the replacement of damaged beam ( where the fatigue took place ) is more safe .