Abstract: “One of the critical issues for a long suspension bridge is the vibration induced by wind. The excessive vibration on long suspension bridge owing to bridge flexibility may cause the bridge ’s aerodynamic instability and vehicle accidents. Therefore, in the present study, the optimum ratio for the span and turning angle to bridge width was investigated. The analysis was carried out on bridge with total span of 470m, main span 270m and side span 100m, using variations of bridges width ranging from 9 m to 22m. SAP2000 program was used to analyze the stability behavior of the suspension bridge under wind load at speed of 35m/s. The results of analysis shows that the optimum ratio of spa n to width bridge is 0.034L or L= 29.375b . When the turning angle was taken into consideration in the analysis , it will result in increasing the bridge’s stability , decreasing natural freq uency of the structure a nd increasing stress es on the cable s . Further , it was a lso found that the deflection a”

Keywords: suspension bridge, wind, vibration, stability analysis, turning angle