Investigation on dynamic effects of frame with specially shaped columns subjected to column failure

Dynamic effects caused by sudden failure of the vertical load-bearing component are an important factor affecting the progressive collapse of building. In order to study the influence of dynamic effects on structure, a collapse experiment of a 1/3-scale, 2×3-bay and 2-story reinforced concrete frame with specially shaped columns with sudden column removal were carried out. The displacement response, reinforcement and concrete strains during the collapse of the frame were studied to reveal the dynamic response of structure such as deformation and internal force redistribution. Experimental results show that the influence of dynamic effects on structure at the moment of component failure was not significant. The structure was still in the elastic stage and collapse did not occur, indicating that reinforced concrete frame designed according to Chinese codes has a good behavior against progressive collapse caused by sudden loss of a first floor column. A progressive collapse dynamic analysis model was established using the alternate path method based on the test frame, and the relationship between the dynamic amplification factors and failure time were derived. Transient time history analysis was carried out on the finite element model of experimental frame using OpenSees to obtain the variation of dynamic amplification factor with the failure time.