Analysis of structurally discontinuous reinforced concrete building frames using the ASI technique

The Adaptively Shifted Integration (ASI) technique, which produces the highest computational efficiency in the finite element analyses of framed structures including static and dynamic collapse problems, is applied to structurally discontinuous problems of reinforced concrete building frames. A new numerical scheme based on the updated Lagrangian formulation (ULF) adaptation of the ASI technique is developed, by modeling the fracture of a section by a plastic hinge located at the exact position with a simultaneous release of resultant forces in the element. By using the algorithms described in this paper, the analyses became possible even by the conventional displacement-based finite element codes, and sufficiently reliable solutions for practical use have been obtained in the explosive demolition and seismic damage analyses of a five storied, five span RC building frame. The present technique can be easily implemented with minimum effort into the existing finite element codes utilizing the linear Timoshenko beam element.