Abstract：The structural performance of arch bridge serviced 20 years was inspected and its risk was analyzed. The effects of multi-factors ( i. e. impact coefficient, capacity reduction by damages, and overloading of live loads) on the bridge performance was considered. The arch was strengthened by increasing section size of the footing and bonding steel plates at critical sections along the arch. The results show that impact coefficient, damage, and overloading significantly affected structural performance of the arch. Compared with the original design, the negative effects of safety indicator of the sections reduced by 22%, 54%, and 50% respectively.Meanwhile, more sections of the arch could meet with the requirement of structural capacity. Through the strengthening, the loading capacity of all sections met the design requirements. The study provided a reference for rehabilitation of arch bridges.

Keyword：carrying capacity of main-arch;impact coefficient;capacity reduction by damage;overloading;bridge reinforcement;