I have heard that loads on masonry anchors and ties during a wind storm can be many times greater than what the tributary area would indicate. How can this be? Shouldn't the loads on the individual ties be equal to the wind load times the tributary area?
During a wind storm some masonry anchors and ties will be loaded more than others. If the walls are connected to a very flexible backup, the ties near the top and bottom of the wall will carry most of the wind load back to the structure. The ties near the midheight of the wall will receive almost no load at all. Depending on the wall support, the positioning of anchors and the flexibility of the backup, some anchors may have four or more times the load calculated by a tributary area analysis.