On the use of fixed point theory to design coupled core walls
The use of Fixed Point Theory (FPT) to optimize the design of coupling beams in coupled core wall (CCW) systems is demonstrated. The basis for optimization is minimizing the transmissibility of horizontal ground motion by appropriately linking two coupled wall piers having different dynamic properties with beams having appropriate stiffness and damping characteristics. Using 21 example CCW structures illustrating a range of pier properties, it was shown that the resulting optimization of coupling stiffness is quite small and other design considerations will require stiffer, non-optimal coupling beams. Nonetheless, the potential to leverage the small amount of coupling available in a ‘slab-coupled’ series of wall piers in order to reduce transmissibility is suggested by the findings of this study.
Method of Estimating Equivalent Mass of Multi-Degree-of-Freedom System
To attain the optimum design of vibration controllers to suppress the many resonance peaks of machine structures, it is necessary to know the equivalent mass at the location at which the controller is mounted. This paper shows two ways of estimating equivalent mass, one is a modal analysis method, and the other is called the mass response method which utilizes the change in natural frequency of a structure when an additional mass is attached. The first method is useful for identifying a modal mass having a physical meaning, while the other method is more suitable for application to experimental analysis. The accuracy of these methods are compared by applying them to three kinds of mechanical structure.
Classification Methodology for Coupled Shear Walls
This paper presents guidelines for classification of ductile coupled shear walls (CSWs). It includes two parts: the evaluation of the degree of coupling (DC) between the walls and the coupling beams, and the classification of CSWs. In present practice, DC is defined as the percentage of the base overturning moment carried by the axial tension and compression forces resulting from shears in the coupling beams. The evaluation of DC requires a structural analysis of CSW, which presents serious shortcomings during the preliminary proportioning process. A simple method is proposed in this paper for the evaluation of DC without need for structural analyses. A classification method based on the dynamic properties of CSWs is also proposed. This allows the classification of CSWs into one of the following three categories: a series of linked isolated walls, CSWs, and walls with openings (pierced walls). Finally, numerical examples demonstrate the applicability of the proposed methods. This paper is thought to be ve...