NUMERICAL MODELING OF JOINT DUCTILITY IN STEEL AND STEEL- CONCRETE COMPOSITE FRAMES

The paper presents a study on numerical modeling of typical joints in steel and composite steel- concrete frame structures for the purpose of the global progressive collapse analysis of multistory buildings. The difficulty in such analyses is to efficiently model the response of joints with consideration of all the aspects of structural detailing, like the postwelding properties of steel, the weld size effect, detailed bolt connection geometry including the bolt head, nut and washer, as well as to merge responses of two materials into one representation in case of composite joints. The problem is investigated using nonlinear dynamic computer simulations carried out using general purpose program LS-DYNA. The feasibility study is focused on identification of modeling parameters affecting the final results and on development of a plan for hierarchical verification and validation.