Yu Lin Chung

Seismic resistance capacity of high-rise buildings subjected to long-period ground motions: E-defense shaking table test

A series of large-scale shaking table tests is conducted for a high-rise building structure subjected to long-period ground motions. A test method is developed to preserve the original dimensions of structural members of a prototype building that has 21 stories with a total height of 80 m. The test specimen consists of a four-story, two-span by one-bay steel moment frame and three substitute layers placed on top of the moment frame. The substitute layers, which consist of concrete slabs and rubber bearings, are arranged to represent the upper stories of the prototype. From preliminary vibration tests, equivalence between the test specimen and the prototype is verified in terms of the lower mode natural periods and corresponding mode shapes. The test specimen when subjected to long-period ground motions exhibits cumulative ductilities more than four times those expected in Japanese seismic design, while the maximum story drifts remain nearly the same as those considered in the design. A number of cyclic in...

Shaking Table Test of the Taiwanese Traditional Dieh-Dou Timber Frame

ABSTRACT This article attempts to explore the dynamic behavior of traditional Dieh-Dou timber structure under different combinations of structural forms and vertical loads. Using time-history record (TCU 084) from the Chi-Chi earthquake, two semi full-scale specimens (Symmetric and Asymmetric) were tested. Results showed that the Symmetric specimen tends to be damaged more easily and faster than the Asymmetric one. Damage pattern generally begins from the bottom Dou members and subsequently spreading upwards to the upper Dou, horizontal Gong members, and adjoining Shu members. Friction force between the contact surfaces is crucial towards the maintenance of overall structure. Increase vertical loadings have significant effect on the natural frequencies and global stiffness of the structure. Using the Single-Degree-Of-Freedom (SDOF) system, the derived stiffness is generally in good agreement with the dynamic results of both forms. This study suggests that the effects of increasing vertical loadings should be taken into consideration for future evaluation.

Structural behavior of traditional Dieh-Dou timber main frame

ABSTRACT Under different combinations of horizontal and vertical loads, a total of three quasi-static cyclic tests were conducted to investigate the structural behavior of the Dieh-Dou timber frame. Typical deformation patterns include column rocking, joint rotation around the primary beam-column and column Dou-column regions, vertical shear around the column mortise, embedment around primary beam-column regions, and vertical shearing around the mortise regions of the Dou members. Visible deformation generally began from 1/30 rad onward. The column-restoring force contributed mainly to the frame’s moment resistance when displacement is small. When frame deformation exceeds 1/50 rad, bending moment from the primary beam dominated the global restoring force. Hence, the column-restoring force and the primary beam-column connection generally undertake the primary moment-resisting mechanism while the complex bracket structures above the primary beam play a secondary role. Based on the embedment theory and semi-rigid spring concept, a new theoretical model was developed to estimate the global behavior of the Dieh-Dou main frame. Although the prediction tends to be on the conservative side, the predicted model is generally in good agreement with the observed results.