Experimental and Analytical Study on Progressive Collapse of 3D Composite Floor System under Corner Column Loss

Abstract

The propensity of buildings to progressively collapse can be assessed using the alternative path method. Generally, there are three scenarios to be considered: internal column, side column, and corner column removals. Compared to the other two scenarios, the unexpected loss of a corner column is more likely to cause severe progressive collapse due to the weaker restraints from the surrounding elements. In this study, a 1/3-scaled three-dimensional steel-frame-composite-floor system (3D composite floor system) was first tested to failure by a specially designed 3-point loading system under the corner column removal scenario, which provides the basic information for the verification of the proposed model. This model is established based on the principle of energy balance between work done by external loads and internal strain energy stored in the deformed structure. The internal energy is calculated following the generic characteristics of the component-based method, and it is extended to the composite slab with the help of a newly defined shrinking factor. The model is presented in the form of an incremental procedure so it is able to track the evolution of internal forces and damage of an individual structural component. Comparisons with both the test and numerical simulation results indicate the accuracy and effectiveness of the proposed model in predicting the load–displacement responses of 3D composite floor systems up to failure when subjected to a corner column removal.