Earthquakes constitute a major problem for mankind resulting in loss of lives and structures. Smart structural materials such as Shape Memory Alloy (SMA) suppress the structural vibration in a structure by adjusting the dynamic performance of the structure. SMA rods are unique for their shape memory effect and super elasticity and have been used as structural reinforcement for earthquake retrofits. This research focused on investigating the appropriate percentage of shape memory alloy and steel reinforcements for the least deflection in the column-capping beam of a 3-span composite Matsurube Bridge in Japan subjected to seismic load. Five different earthquake scenarios were used to obtain the best combination of steel and SMA reinforcement in the columns and capping beam for the best resistance to the earthquake response. Data used for simulations were obtained from the bridge components. It was observed that SMA has a high resistance to seismic loads when combined with steel reinforcement and it is therefore recommended for inclusion in reinforced concrete bridges to serve as means of reducing the effect of earthquakes on structures in earthquake prone areas.