The Performance Investigation of Steel Moment Frames With Knee Braces Subjected to Vehicle Collision

Buildings are always affected by a variety of natural and abnormal forces during their operation. Impact of vehicle collision is an abnormal load which is not usually considered in the design of structures. With the spread of terrorist attacks in many parts of the world, investigation the behavior of structures against unusual loadings, such as blast or vehicle collision has been considered. In this study, steel moment frames with knee braces (2, 5 and 8 story) were designed by SAP 2000 software in two-dimensional according to codes guidelines, and then time history analysis of them was performed by SeismoStruct software subjected to impact of light vehicle collision. The responses such as displacement, drift, acceleration of the stories and the base shear of the frames were compared under the effect of light vehicle collision impact with different velocity (from 10 to 120 km/hr). The results show that the velocity 90, 120 and 100 km/hr causes dynamic instability state in frames with 2, 5 and 8 story respectively. The results also show that the performance level of the mentioned frames based on the maximum stories drift and for the different velocities of impact. For example, in the range of impact velocity of 50 to 80 km/hr, the performance level of 2-story frame was "Life Safety" and regarding to 8-story frame, the performance level was "Immediate Occupancy" for velocities 10 and 20 km/hr.