Orthotropic Cyclic Continuum Constitutive Model For Masonry Structures And Comparative Studies

There is a very popular fable, dating back to the early 1800s, about three little pigs that build their houses of different materials and a wolf that tries to catch them by blowing down their houses. From the three houses built from straws, sticks or bricks, only the house made out of bricks withstands the blow of the wolf. Although the moral of the story is unrelated to structural mechanics, the use of bricks (masonry) to symbolize strength and durability is noteworthy. However, despite its broad and impressive use over the centuries, the different material properties of its constituents, as well as their geometric arrangement, make masonry a material with a highly nonlinear and anisotropic mechanical response. Even though masonry structures have been designed to withstand gravitational loads, they are less capable to resist horizontal loads, like cyclic lateral loads from earthquakes, uneven settlements or even floods. In such cases, the structures might exhibit damage or failure in the form of tensile cracking, bed-joint shear sliding, and crushing, splitting or spalling under compression. It is, therefore, crucial to assess the response and the safety of existing structures, especially when the conditions and circumstances of loading change, for example due to climate change, or due to human-induced earthquakes in previously non earthquake-prone zones, as is the case in the area of Groningen in the Netherlands.