How many inches of solid masonry must be provided at girder supports on top of hollow masonry unit foundation walls?

The requirement for providing a minimum of 4 inches of solid masonry at girder supports on top of hollow masonry unit foundation walls ensures structural integrity and stability. This additional thickness serves several important functions.

First, it helps to distribute the load from the girder more evenly over the hollow masonry unit, reducing the risk of potential crushing or damaging the hollows in the units beneath. Hollow masonry units are not designed to bear the same weight as solid units, so the solid masonry acts as a reliable interface between the weight of the girder and the foundation.

Second, the solid masonry provides better resistance to lateral forces and enhances the overall rigidity of the support structure. This is particularly important in seismic areas or locations where wind loads can impart significant lateral stresses.

Lastly, the 4 inches of solid masonry allows for proper anchorage of the girder, ensuring that there is sufficient material to fasten the structural components securely, which further contributes to the overall safety and longevity of the building.

In contrast, the other choices do not align with established building codes or practices for girder supports on hollow masonry units. Less than 4 inches could lead to inadequate support or structural issues, while more than 4 inches may not be necessary and could increase construction costs without providing