A unified theory for predicting the compressive stress-strain curve of concrete block masonry

I-type internal structures are commonly present in concrete hollow block masonry. A unified theory based on I-type internal structures is proposed to analyze types of masonry systematically. In this unified theory, the I-type element represents the I-type internal structure; the equivalent frame is introduced to analyze the interaction between the block and grout; and the characteristic strength of mortar is employed to measure the performance of mortar in masonry. Each subtheory of the unified theory is independent, and the application scope of this theory can be expanded by adjusting the subtheories. The predictions of the unified theory for the compressive behaviors of fully grouted, partially grouted, and ungrouted masonry are well matched with the measured data. Through targeted adjustments, the prediction of this theory for special cases is also accurate. The calculation results suggest that the unified theory can effectively analyze different types of masonry with an I-type internal structure.