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The recent rise of terrorist attacks has reinforced the need for mitigation of damage caused by blast loading on unreinforced masonry walls. The primary goal of the techniques is to prevent the loss of life while simultaneously preserving the integrity of the structure. This paper presents a compilation of recently available literature on blast protection of unreinforced masonry walls. It seeks to present the state of the art in this field, including mitigation techniques considered as well as testing methods selected. Fiber reinforced polymers and polyurea are the two dominant retrofitting techniques being assessed in the field. Other techniques include but are not limited to polyurethane, steel sheets, and aluminum foam. Since there is no widely implemented standard for blast loading test procedures, direct comparisons between the efficiencies of the mitigation techniques proposed are not always feasible. Although fragmentation is an indicator of the efficiency of retrofits, it is currently measured by subjective observation of postblast debris.

Among the control devices considered for dissipating seismic energy and reducing structural vibrations is the magnetorheological (MR) damper which consists of a hydraulic cylinder filled with a suspension of micron-sized, magnetically polarizable iron particles capable of reversibly changing from free-flowing, linear viscous fluid to semi-solid with the application of a magnetic field. Several algorithms have been proposed for regulating the amount of damping provided by MR dampers. An attractive option is the use of fuzzy controllers because they are simple, intrinsically robust, and they do not depend on a model of the system. Tuning of these controllers, however, has shown to be a difficult task because of the large number of parameters involved. This paper proposes a self-tuning fuzzy controller to regulate MR dampers' properties and reduce structural responses of single degree-of-freedom seismically excited structures. Robustness to changes in seismic motions and structural characteristics was assessed by subjecting a rigid and a flexible building to different earthquake records. Results show that the self-tuning controller proposed effectively reduced responses of both structures to all earthquakes considered. In addition, results were compared to those of a fuzzy controller with constant scaling factors and to those of two passive strategies: "passive on" and "passive off", where the current to the MR dampers was set to its maximum allowable value, and zero, respectively.

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