Multi-phase Inverse Perturbation Method for Generation of Design Sequences of Non-proportional Damping Building Structures and Development of a Computer-aided Generation Sysem of Stiffness Designs

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The purpose of this project is to develop a general computer-aided generation system of stiffiness designs for non-proportional damping systems via a new multi-phase inverse perturbation method in a complex-number plane. The following results have been obtained in this project.1.A new method of stiffness designs has been developed for a shear building model with viscous dampers at the interstories. First, a sequence of stiffness designs has been generated with respect to a sequence of a representative parameter of damping coefficients of viscous dampers under the decoupling approximation such that each mean peak maximum interstory drift would coincide with the specified value subject to a set of spectrum-compatible design earthquakes. The initial design has been obtained via the method developed by the present senior researcher. The second perturbation procedure has been developed with respect to a level parameter representing the effect of off-diagonal terms.2.A new method of stiffnes … More s design has been developed for a shear building model with Maxwell-type viscous dampers. A sequence of stiffness designs has been generated with respect to a sequnece of flexibility of spering elements in the Maxwell-type viscous dampers such that each mean peak maximum interstory drift would coincide with the specified value subject to a set of spectrum-compatible design earthquakes. The initial design has been obtained via the method developed in 1.3.A shear building supported by a prescribed pile-soil system is subjected to bedrock earthquake input. A new design procedure has been presented for generating a sequence of stiffness designs satisfying the constraints on interstory drifts. The mean peak interstory drifts of the shear building subjected to a set of spectrum-compatible ground motions at the bedrock have been evaluated by a model combination rule. Tuning of the fundamental natural period of a shear building with a fixed base with that of a shear beam ground results in a non-monotonic sequence of stiffness designs with respect to a ground stiffness parameter and previous approaches can not be applied to such a problem. This difficulty in finding such a non-monotonic sequence has been overcome by utilizing the ground siffness parameter and the superstructure stiffness parameter alternately in multiple design phases and by developing a new multi-phase perturbation technique. Less