The Earthquake Engineering Online Archive

Infill panels: their influence on seismic response of buildings

Axley, James W.; Bertero, Vitelmo V.

UCB/EERC-79/28, Earthquake Engineering Research Center, University of California, Berkeley, 1979-09-01, 205 pages (555.1/A95/1979)

The problem of modeling the stiffness contribution of infill panels to elastic frame-infill systems is discussed. A set of dimensionless parameters is developed that is sufficient to define the nature of this stiffness contribution. A method for modeling the structural behavior of frame-infill systems is proposed wherein it is assumed that the primary structural system (the frame) constrains the form of the deformation of secondary structural elements (the infill panels). It is suggested that such a constraint approach may be considered to be generally useful in modeling the behavior of certain classes of secondary structural elements. This constraint approach, as developed in this paper, is an approximate finite element substructuring technique that has the effect of reducing the analytical complexity of frame-infill systems and leads naturally to the development of a group of computationally attractive 12 degree-of-freedom infill elements that may simply be "plugged" into conventional frame analysis programs. Four infill elements are presented corresponding to completely and partially infilled frames with complete and partial constraint assumptions considered. Other possible elements are discussed briefly. The suitability and accuracy of the constraint approach is evaluated. These infill elements are then utilized in a detailed three-dimensional elastic analysis of a building that suffered extensive damage during the Feb. 1976 Guatemalan earthquake. The nature of the response of this building to seismic excitation is considered and the influence of the infill upon this response is discussed in detail.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-79-28.pdf (16 MB)