Experimental and analytical studies on double wythe masonry walls.

摘要

Double wythe masonry walls made of concrete block and brick wythes that are separated by an air space and insulating material and joined together by metal ties are used widely in buildings in North America. This type of wall is aesthetically pleasing and provides good insulating capabilities if properly designed and constructed. The interaction between the two wythes and their individual contribution in carrying the imposed loads depend on many factors. Some of these factors are the type of ties, cavity width, load eccentricity, and the slenderness ratio of the wall. To date, there is a lack of a rational analysis which would consider these factors and most design standards either neglect the contribution of the brick veneer in resisting the applied loads or include it in a very approximate way.;This thesis contributes to the experimental database on double wythe wall behavior and presents a simple, yet accurate, analysis method for this type of masonry wall. The experimental program involved testing thirty double wythe masonry walls and sixteen single reference walls. Both eccentric in-plane loading and lateral out-of-plane loading were used. Test variables were the type of ties (three tie types were used), the cavity width (38 mm, 76 mm, and 114 mm), the load eccentricity (10 mm, 23 mm, and 46 mm), and the slenderness ratio of the wall (height to thickness ratios of 20 and 30). The load-deflection plots of the walls are presented and non-dimensional curves are used to analyze the results.;The analysis technique presented in this thesis is based on the results of a finite element analysis of a masonry couplet from which empirical formulae for the effective flexural rigidity of a masonry wall are developed. In addition, equations which relate the moments in the block and brick wythes and the ties were derived. The equations were used in a one dimensional analysis of masonry walls. The method rationally accounts for material nonlinearities, flexural tensile bond failure mechanism, type of ties, cavity width, load eccentricity, slenderness ratio, and P-