Approximate Analysis Methods for Modeling Structural Collapse

Design engineers increasingly need to assess the performance of structures responding to extreme loading scenarios. Such scenarios often involve considerable inelastic behavior, and examples include progressive collapse, blast loading, and earthquake response. Concrete slabs can contribute significantly to overall structural performance during such events, and the ability to efficiently include nonlinear slab behavior in structural models would be a valuable addition to both bridge and building design. High fidelity, nonlinear finite element analysis programs do have the ability to predict geometric and material nonlinear behavior of both beam and shell elements, but these programs typically demand heavy personnel commitments and computational resources. Many basic structural analysis programs commonly used in design offices do allow nonlinear behavior in beams, but few currently allow nonlinear behavior in shell elements. The nonlinear shell formulations that are now offered by some commonly used basic structural analysis programs are often insufficient, difficult to use, or computationally intensive. Therefore, design engineers would benefit from a method to compute the inelastic response of slabs using familiar analysis tools. This paper presents the development of a procedure to represent the inelastic response of slab components using a beam element mesh in a structural analysis program frequently employed by design engineers.