Takamatsu, Keisuke

Research on Seismic Retrofit Using Additional Outside Frame With Built-In Dynamic Mass and Dampers

Abstract eng:
This study proposes a new seismic retrofit system which uses soft spring devices connecting the main structure and a subsystem using response control devices. The subsystem is composed of additional outside frames which are attached on the outside of the main structure to control seismic response. The seismic retrofit methods by response control devices can be classified into two major methods. One is the method of using the response control frames on the outside of existing building. The other is the method of attaching them in frames of existing building. This study draws attention to the former method. In this study, there are two common approaches to connect the main structure and subsystem:(1)using high rigidity members so that they respond as an integrated structure; and (2) using the coupling damping method which is connected with the response control devices between the main structure and subsystem without them. In the former case, it is often difficult to attach the rigid members to the main structure (e.g., concreate) because of significant material degradation. In the latter case, a large mass is required for the subsystem because the performance of main structure is determined by the mass of the subsystem. This study addresses the use of the dynamic mass (D.M.) for the outside frame to improve the seismic retrofit system to avoid the above problems. In this new system soft springs are used for the connection devices rather than rigid members. It is also possible to increase the mass of the subsystem by using the damping frame as the D.M. Such improvements have been achieved by the use of the D.M. to control the mass term in the equation of motion. This paper derives a theoretical formula for this system. Based on “invariant point theory,” optimal tuning and optimum damping formulas are derived. In addition, by expressing these formulas as function of natural periods, a multi-degree of freedom system can be applied with eigen-value analysis. The effectiveness of the proposed approach is illustrated with a practical design method and an example of its application.

Contributors:

Kuroda, Ryuji

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

Text je chráněný podle autorského zákona č. 121/2000 Sb.