In masonry installation, what size reinforcing bar must be spliced using a mechanical connection?

In masonry installation, the requirement for splicing reinforcing bars using a mechanical connection is essential for maintaining structural integrity and ensuring compliance with building codes. Splicing refers to how two pieces of rebar are connected to function as a single continuous reinforcement within the masonry structure.

The correct answer relates to the size of the reinforcing bar that necessitates a mechanical connection. For rebar sized No. 9 or larger, a mechanical connection is specified to ensure that the load transfer between the bars is robust enough to handle the stresses imposed during use. Mechanical connections are designed to provide a reliable bond that can carry tensile loads effectively, which is particularly critical in larger bars due to their higher capacity and potential for significant stresses.

Rebar sizes smaller than No. 9 typically allow for lap splices, which may be sufficient to meet the requirements for structural integrity in less demanding applications. However, for larger bars, the complexities in load distribution and potential for slippage necessitate a more reliable connection method, thus making the mechanical connection the appropriate choice for sizes No. 9 and larger. This is why No. 9 or larger bars dictate the requirement for mechanical splicing in masonry applications.