Steel triangulated (open web) girders are provided with camber to compensate for deflection under load. Out of the total design camber, the part corresponding to dead load is called dead load camber. The balance is called live load camber which should be available as visible and measurable camber in the girder when not carrying load.
Loss of camber can be mainly attributed to :
a) Overstressing of members beyond the elastic limit
b) Overstressing of joint rivets
c) Loose rivets