Experimental method of the full scale shaking table test using the inertial loading equipment

Abstract

Under the recent severe earthquakes, i.e. Northridge Earthquake (1.17.1994,U.S.A) and Hyogoken-Nanbu Earthquake (1.17.1995, JAPAN), many moment resistant steel frames showed typical mode of fracture at the beam-to-column connections. It is strongly requested to clarify the mechanism of fracture at beam-to-column connections. The most effective method to examine the process of fracture in the structural element of the building structures under severe earthquakes is the full scale shaking table test. But, it is not able to carry out the shaking table test on full-scale structures because of the capacity of the shaking table. When reduced-scale model is used as the specimen, the scale effect and the strain rate can’t be reflected. Both of the scale effect and strain rate are the primary factors of fracture. In this paper, a new experimental method of the full scale shaking table test is proposed. The main feature of this experimental method is characterized by the use of the inertial force equipment. The inertial force equipment consists of a loading frame, 200 ton of counter weight and isolators. The loading frame was set on the shaking table supported by isolators. Specimens used in this experimental method were partial frames taken out from middle-rise building structures. Using partial frame as the specimen, full scale and real time dynamic loading test was realized. The test set-up was composed by a specimen, the inertial force equipment and loading beam which transmits the horizontal force to the specimen from the inertial force equipment. This test set-up, regarded as a single degree of freedom system, makes it easy to understand the dynamic behavior of the test set-up including a specimen. The shaking table used in this test is one of the largest shaking tables in the world, and it is can apply 100 kine velocity to 200 ton of weight. So, dynamic loading test of structural elements up to their collapse becomes possible.