Quantitative Prediction of Long-Period Ground Motions of Tokyo Bay Area From the Tokai Earthquake

Takahashi

2011

JSDD

This paper presents a response evaluator as a semi-active control method for a base isolated building in long-period earthquake response analysis. The absolute acceleration of each story and the relative displacement of an isolated layer are the input signals and the switching parameter for the damping coefficient is the output signal of the response evaluator. The response evaluator is designed by a multilayered neural network, and a genetic algorithm is used to adjust the neural network parameters which determine the performance of the response evaluator. Four oil dampers are installed in the isolated layer and each damping coefficient of the dampers is set to a different value to correspond to the various characteristics of earthquake motions, then the total damping force of the isolated layer is multi-step values, regardless of whether using oil dampers with two-step damping coefficients. By the numerical simulation with the proposed semiactive control method, both the acceleration of each story and the displacement of the isolated layer, which are in a trade-off relationship with each other, are reduced compared with the acceleration in the case of all damping coefficients being small (Soft) and the displacement of the isolated layer in the case of all damping coefficients being large (Hard).

Section: Characteristic Of Long-period Earthquake Motionmentioning

confidence: 99%

Section: Journal Of System Design and Dynamicsmentioning

confidence: 99%

Semi-Active Control for Base Isolated Structure Using Response Evaluator Subjected to Long-Period Earthquake Ground Motion

Takahashi

2011

JSDD

“…These waves are also applied to design the maximum passive response. Thus, there are nine types of waves referred to in this paper for consideration, including the three waves and Kanto [4], Nankai [6], Tokai [7], El Centro, Taft, Hachinohe. Amongst them, the acceleration waveform of the three types of waves including JMA Kobe, Tokai-Tonankai and BCJ, and the velocity response spectrum for 5% of damping are shown in figs.…”

Section: Seismic Motionmentioning

confidence: 99%

Semi-active control design for base isolated structures with switching damping coefficient of oil dampers

WIT Transactions on the Built Environment

Takahashi²

2013

In Japan, after the Hyogo-ken Nambu Earthquake in 1995, base-isolated structures spread rapidly. Now, there are about 2,800 base-isolated buildings (apartment complexes account for 45% and hospitals for 12%) and about 4,300 base-isolated houses in Japan. Base-isolation technology was effective in the Tohoku Earthquake 2011, off the Pacific coast. This paper presents the methods behind semi-active control design for base-isolated structures with oil dampers whose damping coefficient can be set in two levels: applying two different damping coefficients based on the proposed control design. The damping coefficients of the oil dampers are different to each other. The control objective is the reduction of both the displacement of a base-isolated layer and absolute acceleration of a base-isolated building, which are trade-offs against each other. The layered neural network with the Genetic Algorithm (GA) is applied to the semi-active control design. Absolute acceleration of the building and displacement of the isolated layer are the input signals of the neural network, and the switching parameter for the damping coefficient is the output signal of the neural network. The GA is used to adjust the neural network parameters that decide the control performance. The target of the control design is specified to permit the displacement of the base-isolated layer to the upper limit and to restrain the increase of building acceleration. We study the control performance of the proposed control method using several kinds of earthquake motions in the computer simulation.

Semi-Active Control for Base Isolated Structure Using Response Evaluator Subjected to Long-Period Earthquake Ground Motion

Takahashi

2011

Trans.JSME(C)

This paper presents a response evaluator as a semi-active control method for base isolated building in long-period earthquake response analysis. The absolute acceleration of each story and relative displacement of an isolated layer are the input signals and switching parameter for the damping coefficient is the output signal of the response evaluator. The response evaluator is designed by a multilayered neural network, and a genetic algorithm is used to adjust the neural network parameters which decide the performance of the response evaluator. Four oil dampers are installed at the isolated layer and each damping coefficient of the dampers is set to different value to correspond to various characteristics of earthquake motions, then the total damping force of the isolated layer is multi-step values regardless of using the oil dampers with two-step damping coefficient. By the numerical simulation with the proposed semi-active control method, both the acceleration of each story and the displacement of isolated layer which are trade-off relations with each other are reduced compared with the acceleration in case of all damping coefficient small (soft) and the displacement of isolated layer in case of all damping coefficient large (hard).