The fillet of the comer part of steel bridge piers is significantly small, and a fatigue crack appears in the fillet due to the excessive stress concentration. Then, a splice plate is fixed to the piers by the high strength bolts as an emergency reinforcement against the fatigue cracks. A new constructional process by using the thermal prestressing method was developed herein. It was predicted that the development of the fatigue cracks could be prevented by this thermal prestressing method. The fatigue crack was so examined through the fatigue test, that the stiffening effect was actually confirmed. Furthermore, it is suggested that the reinforcement was necessary for the comer part on the compression side of the bridge pier in order to avoid the fatigue cracks due to the excessive stress concentration.
