E-Defense Tests on Full-Scale Steel Buildings Part 2 - Collapse Experiments on Moment Frames

A major research project on steel buildings utilizing the E-Defense three-dimensional shake table facility is underway in Japan. It involves several studies on moment frames, innovative methods for new or existing buildings, protective systems, and nonstructural elements. As one of the studies, a challenging seismic experiment to simulate collapse of a full-scale bulding comprising the moment frame will be conducted in September 2007. Collapse is defined as the state where the structure loses its ability to sustain gravity loads. To-date, only a few full-scale tests have been conducted for the multi-story steel moment frames, and none of those simulated collapse. Two decades ago, a 6-story moment frame was pseudo-dynamically tested by static actuators simulating severe earthquakes. Recently, a 3-story moment frame including exterior walls was tested up to an overall drift angle of 1/15 rad, by static loads to reflect the effects of the ground motion that is greater than considered in the current seismic codes. These full-scale tests employed quasi-static loading, since a dynamic loading facility capable of much more realistic simulations was not available. The E-Defense shake table which commenced operation in 2005 is capable of subjecting a full-scale structure to the strongest ground motion recorded in the world. With a 12,000 kN specimen placed on 15m x 20m table, the table can produce a maximum velocity of ±2.0m/s and a maximum displacement of ±1.0m. With the E-Defense shake table, we have the first opportunity ever to simulate the behavior of full-scale structures up to collapse, and to obtain detailed response data. This paper outlines the test plan of collapse simulation, as well as technical issues being addressed during the process of test preparation.