The Earthquake Engineering Online Archive

A mathematical model for predicting the nonlinear response of unreinforced masonry walls to in-plane earthquake excitations

Mengi, Yalçin; McNiven, Hugh D.

UCB/EERC-86/07, Earthquake Engineering Research Center, University of California, Berkeley, 1986-05, 122 pages (515/M39/1986)

A mathematical model is proposed to predict the nonlinear in-plane behavior of clay brick masonry walls when subjected to dynamic excitations. The study has two stages: the development of the form of the mathematical model and the establishment of the parameter functions appearing in the model both using optimization and experimental data. The experiments were carried out using the shaking table of the Earthquake Engineering Research Center, Univ. of California, Berkeley. The experiments involved in-plane horizontal earthquake excitations. The intensity of excitation, starting with a small value, was increased gradually through the beginning of cracking until damage was complete. Time histories of accelerations and displacements relative to a fixed frame were recorded at the upper and lower edges and at the mid-length of the wall specimen. The form of the nonlinear model was established by extending the effective modulus model, developed previously by the authors in conjunction with studying the linear dynamic behavior of masonry walls, to the nonlinear range. The model contains two types of parameter functions. One describes elastoplastic stresses and depends on strains; the other describes viscous stresses and is a function of strain rates. Model predictions are compared with experimental results, and a criterion is proposed for the prediction of the amount of damage caused by an earthquake.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-86-07.pdf (7 MB)