NON-LINEAR FEM DYNAMIC ANALYSIS OF 3D STEEL FRAME WITH INTERMEDIATE DUCTILITY UNDER CRASH LOADING

Sudden impacts may afflict wide damages on structures. Therefore, it is required to investigate these incidents when designing structures. In this paper, different failure types in steel column are investigated and, for each type, numerical results are compared with the experimental ones for the sake of validation. Initiation and development of structural failure due to truck collision with one of the corner columns was modeled dynamically and was investigated. For this purpose, the three dimensional moment frame steel for a 4-story building with medium ductility using ETABS software under dead, live, and seismic load was designed; then, was loaded with the ABAQUS software under impact load. For validation of the molding process, the experimental results in the field of vehicle collisions with steel columns were used. The nonlinear dynamic analysis was used for simulation of impact caused by the collision of trucks having different masses and speeds. Using the appropriate plasticity and shear failure model, the stresses and internal forces in the structure, especially in the damaged column, were extracted. To study the effects of various parameters on structural response, a parametric study was conducted, and the results were compared with each other. The results showed that mass and speed play an important role in building damage. When the collision occurs, the entire structure, including columns, is affected by the dynamic load. As a result, the current method of elimination of only one column and applying static loading to the structure cannot show progressive collapse accurately.