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

Low-cycle fatigue effects on lifetime of circular bridges piers considering rocking-enable shallow foundation

Cyclic loading during large earthquakes induces low-cycle high-amplitude strain in longitudinal bar of bridge column piers. This phenomenon is known as low-cycle fatigue, which reduce design life of column pier due to longitudinal bars fracture. After recent large earthquakes (e.g. Christchurch in 2011), resilience became a public demand instead of conventional design methods. While conventional design methods mostly relay on plastic hinge formation in column pier as an earthquake resistance system (ERS), modern methods try to reduce demands on ERS in order to assure of resilience. Rocking shallow foundation (RSF) is an earthquake demand reduction system. This research demonstrates how RSF, prevent column pier design life reduction due to low‐cycle fatigue. The obtained results confirm that RSF needs significantly smaller foundation design moments that could result in avoiding costly pile foundation and more importantly, extend life of column piers more than conventional design strategie

Multi-objective optimization of hydraulic engine mounts vibrational behavior by non-dominated sorting genetic algorithm

Engine mounts are designed to hold the engine and isolate its vibration from the chassis of the vehicle. For optimum system performance, the mount must have high dynamic stiffness in the low-frequency range and low dynamic stiffness in the high-frequency range. As the conventional elastomeric mounts fail to satisfy such requirements due to their frequency-invariant behavior, the hydraulic engine mounts have been proposed, which provide appropriate dynamic stiffness employing two fluid-containing chambers. These two chambers are connected through a high-damped pass named inertia track and a floating plate named decoupler. In this paper, the low-frequency range response of a hydraulic engine mount has been studied using a discrete model. The effect of its parameters on the dynamic stiffness, damping ratio, and transmissibility of the mount is discussed. It is shown that increase in dynamic stiffness and damping ratio of the hydraulic engine mount is in contradiction with the decrease in its transmissibility. Hence, a multi-objective non-dominated sorting genetic algorithm has been used to achieve the desired results and the corresponding Pareto front is plotted. It is observed that upper chamber compliance and the effective area of the mount are the most dominant parameters in the optimization procedure. Also, a penalty function is used to transfer the maximum transmissibility out of the engine operation frequency range. Finally, the optimization results for transmissibility, damping ratio, and dynamic stiffness are presented for three series of parameters. It can be concluded that on the limit points of the Pareto front, which correspond to the one-objective optimization, the professed objective is optimized, but on the contradictory objective, no improvement is observed. There are points on the Pareto front where all the three objectives are optimized simultaneously. Therefore, as the transmissibility decreases and its maximum value falls out of the operating frequency range, the damping ratio and dynamic stiffness are increased

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