Koichi Takanashi

A New Structural System Using Innovative High-Strength Steel Aiming at Zero Earthquake Damage

This research is a step towards the creation of new structural systems for urban buildings that can withstand even mega earthquakes (Japanese Meteorological Agency, JMA, seismic intensity scale of 7). A new structural system was developed that provides not only high earthquake resistance but also considerable reduction in injury to residents inside buildings and mitigation of damage to facilities, allowing the buildings to continue to be used even during and immediately after a severe earthquake. This paper outlines the new structural system and describes the earthquake resistance performance based on seismic response analysis of a full-scale model of the structural system. Finally, the dynamic tests conducted on the full-scale test structure are explained, and the dynamic performance is discussed comparing it with the results of dynamic analysis.

On-line computer test control method and its application to earthquake response simulation of steel structural models☆

Abstract The on-line computer test control method (the on-line test) is a combined test and numerical analysis to simulate the earthquake response behavior of structural systems. This paper reports on the basic procedures and software and hardware techniques of the on-line test. Two on-line tests applied to steel structural models are introduced, and the accuracy of the responses obtained by the on-line test is demonstrated. The paper also states the problems and future research needs for the further development of the on-line test.

Response observation of scaled model structures to strong earthquakes

Abstract Scaled model building structures with intentionally reduced seismic strength from one-third to one-half were constructed in 1983 for long-term observation in order to collect earthquake response data and research failure mechanisms during earthquakes. A monitoring system was installed in the structures as well as in the surrounding soil. Since then, a great deal of data has been recorded for many earthquakes. Among them, various kinds of data describing response behavior during four strong earthquakes were successfully collected. These data are examined in this paper. Some tentative conclusions are drawn for elastic-plastic behavior, interactions between structures and soil, and soil behavior.

SEISMIC DESIGN AND EVALUATION OF PERFORMANCE BASED ON MEASUREMENT OF RESPONSE-CONTROLLED AND LINKED STRUCTURAL SYSTEM OF OVER-TRACK BUILDING

Response-controlled and linked structural system is suggested to over-track buildings as a system with the applicability. About the example that applied response-controlled and linked structural system to an over-track building, possession performance as the building was identified by earthquake response analysis. At the same time by analysis of the maximum earthquake prescribed in design standard for railway structure, the performance was inspected as the railway structure. By an examination in a station building, vibration characteristic of an over-track building was evaluated and inspected the effectiveness of the adopted system.

SEISMIC RESPONSE CHARACTERISTICS BASED ON ENERGY BALANCE OF RESPONSE-CONTROLLED AND LINKED STRUCTURAL SYSTEM OF OVER-TRACK BUILDING

As a simple damage control structure to apply to over-track buildings with many restrictions on design and construction, response-controlled and linked structural system is effective. In order to make fixed quantity evaluation of the response reduction effective, the validity of the response evaluation by energy balance can be verified by lumped mass system model. Large effect of energy absorption is provided by the combination that is off the most suitable setting in linear range. The effect becomes small in non-linear range, but also large energy absorption is provided by using together with the vibration system including internal damping mechanism.

Recent Achievements in Substructuring on-line Pseudodynamic Tests at IIS

Structural response tests are necessitated to confirm performances of structures based on a design method. The shaking table test is suitable for verifying overall response behavior of the structures, while the on-line or the pseudodynamic test is a powerful tool for large scaled structural model tests. The on-line test is much more utilized by combining the substructuring method in the numerical analysis with the test procedure. The substructuring on-line test technique has high potential particularly to obtain response behavior of buildings with structurally complex frameworks. This paper describes the basic scheme of the substrucring on-line test and recent achievements at Institute of Industrial Science (IIS), University of Tokyo.

Experimental behaviour of multi-storey steel frames

Abstract Two kinds of test were conducted on three-storey steel frames. One was a static test under monotonically increasing loads, while the other was a pseudo-dynamic test using the on-line earthquake response test technique. The results obtained from the two tests on identical frames showed the possibility of representing dynamic load effects by an equivalent static load. It can be concluded that the seismic static design of frames can be performed based on the results of a static analysis instead of dynamic analyses.