Abstract
It is a general trend to make maintenance free designs for bridge structures. Although the design concept of expansion joints was different from that of bridge structures so far, it will be required to take an expansion joint as a structural element of a bridge as long as the maintenance-free concept is applied to bridge designs.
It is discussed in this paper how expansion joints should be designed and what problems will arise under the maintenance free concept. An experimental study was conducted on a specific expansion joint system (mechanical expansion joint system). Through fatigue tests, several material and structural problems in a joint system were pointed out. Finally, those defects were removed and an improved joint system was proposed.
