| The need of structural rehabilitation and strengthening of masonry structures motivated this study to better understand the deformation and failure mechanism of masonry structures. Although the behavior of masonry under uniaxial and biaxial compressive loading has been investigated by many researchers, experimental studies on how the crack propagates in the masonry are rarely seen in the literature. In this study, quantitative measures of strain localization in masonry are presented for the first time in both deformation and failure modes by using an in-situ optical technique called Digital Image Correlation (DIC). It was found that cracks initiated and propagated through the mortar joints; and finally the stone unit split, which is due to the action of biaxial tension in the stone unit when masonry specimen is compressed. Two stage modeling strategy was adopted to model the seismic behavior of large-scale masonry structure. First, homogeneous equivalent material properties are obtained by using micro-modeling approaches. Then, the equivalent material properties are used to macro-model the seismic behavior of the large scale masonry structure with the finite element software ABAQUS. Elasto-plastic analyses were carried out on the granite masonry structure to compare with experimental results. The well experimental-analytical correlation confirmed the capability of the FVDAM model in predicting the response of masonry structure if the individual mechanical behavior of its constituents (i.e., unit and mortar) is known. Extensive parametric analysis was performed to understand the effect of the mesh size, cell texture, mortar elastic modulus and mortar volume fraction on the equivalent elastic properties. Finally, the obtained homogeneous equivalent material properties were used to seismic assessment of the masonry tower of the Brooklyn Bridge. It was found that the whole tower can retain global structural stability but extensive damages appear in the arch-base connection regions under the design earthquake excitation. |
