A simplified method for assessing the response of RC frame structures to sudden column removal

Column loss is a type of damage that can occur in frame structures subjected to explosions or impacts. The response of such structures largely depends on the capacity of the assembly of elements and on the inertia effects due to the sudden nature of the phenomenon. Frame structures are able to develop various resisting mechanisms that prevent the collapse to progress. The assessment of the robustness often requires complex and detailed numerical modelling. For the preliminary design of a robust frame, simplified methods to assess the effectiveness of the redistribution of the loads after the removal of a member are welcome. In the present paper, an approach based on the idealisation of the damaged structure into a single degree-of-freedom system with an elastic-plastic compliance law is proposed. The output of the method is the dynamic response of a target point, which can serve for assessing the residual safety of the structure. Comparing the obtained results with the outputs of a more sophisticated FE (Finite Elements) analysis, a satisfying accuracy is found

Progressive collapse of structures: A discussion on annotated nomenclature

The study of progressive collapse and structural robustness has advanced significantly after 9/11 event. There is a growing interest in the phenomenon, as well as in the development of numerical and experimental techniques that have led to great progress in understanding the structural robustness and integrity. However, the general ideas, concepts and definitions have been merely changed over the past twenty years. These concepts and definitions are first developed in the framework of a threat-independent methodology, implicitly focused on blast-induced progressive collapse (or other short-term extreme events) in framed structures, and then, generalized to other structural types, mechanisms and triggering events, without scrutinization. In this paper, the current definitions of the terms progressive collapse, initial (local) damage and progressive collapse analysis are challenged, their insufficiency is discussed and possible improvements are provided. The suggested definitions and discussions provide a deeper and more general nomenclature for progressive collapse and related topics

Experimental and Numerical Study of Perforated Steel Plate Shear Panels

Thin perforated Steel Plate Shear (SPS) Walls are among the most common types of energy dissipating systems. The applied holes reduce the shear strength of the plate and allow to decrease the profile size of the members at the boundary of the panel when these systems are used in the typical design of structures. On the other hand, the different fracture locations of these panels are visible when considering the different perforation patterns. This paper reports on the results obtained from the experimental study under cyclic loading of the effect of different hole patterns on the seismic response of the systems and the location of the fracture. According to this, two perforated specimens by different patterns were considered. In addition, a plate without holes for a better comparison of the fracture location was chosen. The results showed that changing the pattern of the holes causes a change in the fracture location. Moreover, in perforated specimens, the amount of shear strength did not reduce suddenly after the fracture phenomenon. In the specimen which was perforated around the web plate, the pinching force was more than any other in the low cycle of the drifts. For this reason, the energy dissipation and initial stiffness were more than up to 3% drift. The experimental specimens were then simulated with a Finite Element (FE) method using the ABAQUS. Finally, a parametric FE analysis on different series of perforated panels, by changing the diameter of the holes and the plate thickness, has been carried out

Experimental and Numerical Study of Perforated Steel Plate Shear Panels

Thin perforated Steel Plate Shear (SPS) Walls are among the most common types of energy dissipating systems. The applied holes reduce the shear strength of the plate and allow to decrease the profile size of the members at the boundary of the panel when these systems are used in the typical design of structures. On the other hand, the different fracture locations of these panels are visible when considering the different perforation patterns. This paper reports on the results obtained from the experimental study under cyclic loading of the effect of different hole patterns on the seismic response of the systems and the location of the fracture. According to this, two perforated specimens by different patterns were considered. In addition, a plate without holes for a better comparison of the fracture location was chosen. The results showed that changing the pattern of the holes causes a change in the fracture location. Moreover, in perforated specimens, the amount of shear strength did not reduce suddenly after the fracture phenomenon. In the specimen which was perforated around the web plate, the pinching force was more than any other in the low cycle of the drifts. For this reason, the energy dissipation and initial stiffness were more than up to 3% drift. The experimental specimens were then simulated with a Finite Element (FE) method using the ABAQUS. Finally, a parametric FE analysis on different series of perforated panels, by changing the diameter of the holes and the plate thickness, has been carried out

Seismic Behavior of Thin Cold-Formed Steel Plate Shear Walls with Different Perforation Patterns

Thin perforated Steel Plate Shear Walls (SPSWs) are among the most common types of seismic energy dissipation systems to protect the main boundary components of SPSWs from fatal fractures in the high risk zones. In this paper, the cyclic behavior of the different circular hole patterns under cyclic loading is reported. Based on the experimental results, it can be concluded that a change in the perforation pattern of the circular holes leads to a change in the locations of the fracture tendency over the web plate, especially at the plate frame interactions. Accordingly, the cyclic responses of the tested specimens were simulated by finite element method using the ABAQUS package. Likewise, perforated shear panels with a new perforation pattern obtained by implementing Topology Optimization (TO) were proposed. It was found that the ultimate shear strength of the specimen with the proposed TO perforation pattern was higher than that of the other specimens. In addition, theoretical equations using the Plate Frame Interaction (PFI) method were used to predict the shear strength and initial stiffness of the considered specimens. The theoretical results showed that the proposed reduced coefficients relationships cannot accurately predict the shear strength and initial stiffness of the considered perforated shear panels. Therefore, the reduced coefficients should be adopted in the theoretical equations based on the obtained experimental and numerical results. Finally, with the results of this study, the shear strength and initial stiffness of these types of perforated shear panels can be predicted by PFI method