ABSTRACT
Most concrete and masonry elements, designed by structural engineers, are subject to combined bending plus compression. In the United States, to ensure appropriate ductility, masonry codes have adopted maximum steel percentages. This chapter presents the applied mechanics equations for cracked elements subjected to bending plus compression for both allowable stress and strength design in a form to more directly understandable ductility and then relates these equations to the current United States masonry and concrete code requirements. In a typical building most masonry walls are subject to bending plus compression. Stress is not proportional to strain. The stress in the masonry is limited to the ultimate stress and the stress in the reinforcement is limited to the yield stress in the reinforcement. Reinforced masonry and reinforced concrete have similar ductility characteristics and are perceived as substitutes for one another in many common types of structures.
