The Earthquake Engineering Online Archive

Elastic-plastic earthquake response of soil-building systems

Minami, Tadao

UCB/EERC-72/03, Earthquake Engineering Research Center, University of California, Berkeley, 1972-08, 159 pages (535/M54/1972)

Effects of plastic soil deformation on the earthquake response of buildings using elastic-plastic finite element models are presented. Nonuniform support excitations were generated statistically to reflect the soil-layer formation of downtown Tokyo. The lumped-mass model of the building is attached through a massless rigid mat to the soil which is represented by a set of finite elements arranged in three rows, representing two typical soil layers of downtown Tokyo. Numerical results of elastic-plastic analyses for 3-, 9- and 18-story buildings with and without basements were compared with those of the corresponding elastic systems as well as buildings with the base fixed at the ground level. As the response of buildings is affected by amplification and attenuation effects of soils as well as the soil-building interaction, the general nonuniform support excitation procedure is indispensable when a discrete type model which represents only a limited portion of the soil is used. A large plastic flow in the soil increases the displacement response but decreases the stress in the superstructure. These effects are more influenced by the reduction in the rotational rigidity rather than by reduction in the translational rigidity of the soil.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-72-03.pdf (10 MB)