Models for Nonlinear Earthquake Analysis of Brick Masonry Buildings.

摘要

Mathematical models are proposed for the three-dimensional, nonlinear earthquake analysis of unreinforced and reinforced brick masonry buildings. In the development of the models, the floors are modeled as rigid diaphragms. For the unreinforced case it is assumed that the wall elements possess only shear resistance and only in their own planes; for the reinforced case the stiffness of wall elements in out-of-plane directions is taken into account. In view of the data obtained from shaking table experiments, a bilinear form for the shear modulus of the masonry wall materials and trilinear form for its viscous counterpart are assumed in the analysis for their variations with the shear strain. For the nonlinear earthquake analysis of masonry buildings, two different approaches are used. The first one involves the use of the equivalent linear method (ELM), which was used successfully by some researches in nonlinear soil-structure interaction analyses. ELM finds the nonlinear earthquake response of a masonry building approximately through iterations. The second approach employs the actual nonlinear model (ANM) whick takes into account hysteretic behavior of wall elements established experimentally in shaking table experiments. To assess the models five example problems are presented. The results indicate that the proposed models can be used reliably in the earthquake analysis of masonry buildings.