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On-line Journal of the IASS

Vol. 49 (2008) No. 2 August n. 158


Earthquake Input Energy at Dynamic Collapse for Double-Layer Cylindrical Lattice Roofs

< Table of Contents for Vol. 49 (2008) No. 2 August n. 158
  • Journal Name: Journal of the International Association for Shell and Spatial Structures (J. IASS)
  • ISSN: (Electronic Version) 1996-9015
  • ISSN: (Print Version) 1028-365X
  • Issue: Vol. 49 (2008) No. 2 August n. 158
  • Pages: 89-96
  • Title: Earthquake Input Energy at Dynamic Collapse for Double-Layer Cylindrical Lattice Roofs
  • Author(s): Y. Taniguchi, P. L. Gould, M. Kurano
  • Keywords: double-layer, lattice roof, dynamic collapse, earthquake input energy
Abstract
Double-layer lattice roofs consisting of various mesh patterns show different static buckling and post-buckling behaviors even if the compression members have the same slenderness ratios. There are not sufficient studies in the literature to finding document to know the effect of these static characteristics on the seismic resistant capacity. In this paper, the input maximum accelerations of seismic motions and input strain energies of lattice structures at collapse are numerically estimated to investigate the relations between these two values and the static buckling and post-buckling characteristics. Double-layer cylindrical lattice roofs are treated with three lattice patterns, which are square-on-square, square-on-diagonal and diagonal-on-square meshes respectively for top and bottom layers. In the numerical simulations, the maximum input acceleration values of earthquakes are gradually increased while monitoring the maximum displacements. The seismic motions adopted are three observed motions and an artificial motion. The collapse is recognized by a sudden increase of the monitored nodal displacements. The results demonstrate that the index of earthquake input energies is more effective than that of the maximum input acceleration for the prediction of the collapse level under seismic loads, because the dispersion corresponding to these kind of motions is smaller for the earthquake input energy. The earthquake input energies at the collapse correspond to the prediction value that is calculated with the velocity response spectrum and large participation factors. It should be noted that further studies are necessary to quantify the relationships between the dynamic characteristics of lattice structures and that of earthquakes. Although a lot of research has been already carried out for moment frame structures in the literature, lattice structures possess a much wider distribution of large participation factors in their natural frequencies.

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