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Earthquakes and Structures Volume 9, Number 6, December 2015, pages 11331152 DOI: http://dx.doi.org/10.12989/eas.2015.9.6.1133 


Critical earthquake input energy to connected building structures using impulse input 

Yoshiyuki Fukumoto and Izuru Takewaki


Abstract  
A frequencydomain method is developed for evaluating the earthquake input energy to two building structures connected by viscous dampers. It is shown that the earthquake input energies to respective building structures and viscous connecting dampers can be defined as works done by the boundary forces between the subsystems on their corresponding displacements. It is demonstrated that the proposed energy transfer function is very useful for clear understanding of dependence of energy consumption ratios in respective buildings and connecting viscous dampers on their properties. It can be shown that the area of the energy transfer function for the total system is constant regardless of natural period and damping ratio because the constant Fourier amplitude of the input acceleration, relating directly the area of the energy transfer function to the input energy, indicates the Dirac delta function and only an initial velocity (kinetic energy) is given in this case. Owing to the constant area property of the energy transfer functions, the total input energy to the overall system including both buildings and connecting viscous dampers is approximately constant regardless of the quantity of connecting viscous dampers. This property leads to an advantageous feature that, if the energy consumption in the connecting viscous dampers increases, the input energies to the buildings can be reduced drastically. For the worst case analysis, critical excitation problems with respect to the impulse interval for double impulse (simplification of pulsetype impulsive ground motion) and multiple impulses (simplification of longduration ground motion) are considered and their solutions are provided.  
Key Words  
earthquake input energy; frequencydomain analysis; timedomain analysis; energy transfer function; connected buildings; passive structural control; impulsive ground motion; long
duration ground motion; critical excitation  
Address  
Department of Architecture and Architectural Engineering, Kyoto University KyotodaigakuKatsura, Nishikyo, Kyoto 6158540, Japan  