Experimental study for improving the behavior of the masonry brick walls with the diagonal load effect

The large earthquakes, which have occurred in the past, resulted in collapse or severe damage to many buildings around the world, consequently caused significant economic losses and took many lives. Most of the built structures in turkey are masonry buildings. The foremost characteristic of these types of buildings is their load-bearing walls which are generally designed to resist vertical loads, building self-load, as well as lateral loads including earthquake-induced forces, wind, or similar dynamic loads. Generally, the structures are required to be retrofitted prior to a likely future earthquake because of the installation and manufacturing errors, poor inspections, modifications in building codes, changes in building usage proposes and etc. The researchers up to now have devoted their studies to develop more effective, economic, and applicable retrofitting methods. Based on the extensive review of the past studies, commonly different materials (FRP, fiber-reinforced mortar, steel plates, steel profiles, hollow steel boxes, steel strips, steel mesh, and reinforced shotcrete, steel mesh and textile reinforced mortar, steel fiber reinforced mortar and concrete strips) are used for the strengthening of load-bearing or infill masonry walls. However, the developed or recommended retrofitting methods are less applicable due to many reasons including difficulties in installation, being too costly, some of them are sensitive to fire, or evacuation of the buildings are required throughout the retrofitting process. In the scope of this study, the retrofitting of masonry (vertically perforated masonry brick walls) buildings are performed using expanded steel plates and shotcrete. Compared to the available methods, this method is less costly, easy to install, and the materials can be recycled. İn this study, a total of 6 experiment specimens, one of them as a reference and the other 5 strengthened, are selected and all of them are subjected to diagonal loading, accordingly their strength and behaviors are examined. The retrofitting process of developed masonry walls began with placing expanded steel plates on both sides of the walls, which were anchored by bolts, afterwards, the shotcrete with 30 mm thickness was applied on it. As the variable parameters of the experimental study; the distance between of the bolts were determined. As a result of the study, it was observed that a large part of the tensile stresses of the experimental elements, retroffitted with expanded steel and shotcrete, was craied out by expanded steel plates. İn addition, cracking due to tensile stress on the walls was prevented. Furthermore, the confinement stress was developed on the strenghtned exprimental specimens, thanks to the anchored bolts, as well as these elements were functioned as a whole and there was no sudden loss in loadings during the whole exprimental process. İt was shown that the shear stress was increased in the exprimental specimens as a result of numerical study. Consequently, a significant increase in rigidity, ductility, shear stress, load-bearing capacities and energy transformation of the masonry wall retrofitted with "expanded steel plate + shotcrete" was observed, indicating that their behavior are getting much better.The large earthquakes, which have occurred in the past, resulted in collapse or severe damage to many buildings around the world, consequently caused significant economic losses and took many lives. Most of the built structures in turkey are masonry buildings. The foremost characteristic of these types of buildings is their load-bearing walls which are generally designed to resist vertical loads, building self-load, as well as lateral loads including earthquake-induced forces, wind, or similar dynamic loads. Generally, the structures are required to be retrofitted prior to a likely future earthquake because of the installation and manufacturing errors, poor inspections, modifications in building codes, changes in building usage proposes and etc. The researchers up to now have devoted their studies to develop more effective, economic, and applicable retrofitting methods. Based on the extensive review of the past studies, commonly different materials (FRP, fiber-reinforced mortar, steel plates, steel profiles, hollow steel boxes, steel strips, steel mesh, and reinforced shotcrete, steel mesh and textile reinforced mortar, steel fiber reinforced mortar and concrete strips) are used for the strengthening of load-bearing or infill masonry walls. However, the developed or recommended retrofitting methods are less applicable due to many reasons including difficulties in installation, being too costly, some of them are sensitive to fire, or evacuation of the buildings are required throughout the retrofitting process. In the scope of this study, the retrofitting of masonry (vertically perforated masonry brick walls) buildings are performed using expanded steel plates and shotcrete. Compared to the available methods, this method is less costly, easy to install, and the materials can be recycled. İn this study, a total of 6 experiment specimens, one of them as a reference and the other 5 strengthened, are selected and all of them are subjected to diagonal loading, accordingly their strength and behaviors are examined. The retrofitting process of developed masonry walls began with placing expanded steel plates on both sides of the walls, which were anchored by bolts, afterwards, the shotcrete with 30 mm thickness was applied on it. As the variable parameters of the experimental study; the distance between of the bolts were determined. As a result of the study, it was observed that a large part of the tensile stresses of the experimental elements, retroffitted with expanded steel and shotcrete, was craied out by expanded steel plates. İn addition, cracking due to tensile stress on the walls was prevented. Furthermore, the confinement stress was developed on the strenghtned exprimental specimens, thanks to the anchored bolts, as well as these elements were functioned as a whole and there was no sudden loss in loadings during the whole exprimental process. İt was shown that the shear stress was increased in the exprimental specimens as a result of numerical study. Consequently, a significant increase in rigidity, ductility, shear stress, load-bearing capacities and energy transformation of the masonry wall retrofitted with "expanded steel plate + shotcrete" was observed, indicating that their behavior are getting much better.