Final answer:
Stirrups or ties connect the top and bottom cords of rebar in concrete to prevent splitting or cracking, similar to how holding a nail with pliers prevents bending. This provides stability and maintains the integrity of the structure.
Step-by-step explanation:
The elements that connect the tops and bottom cords of rebar (reinforcing bar) together to prevent splitting or cracking are called stirrups or ties. These components are essential in reinforced concrete construction because they help to maintain the position of the longitudinal rebar and resist shear forces. Essentially, when concrete is subjected to loads, the ties keep the rebar in place and prevent the individual bars from buckling or splaying apart. The concept is somewhat similar to the old carpenter's trick to keep nails from bending by gripping the center with pliers. When a nail is held firmly, it is less likely to bend because the grip provides additional support and reduces the effective length that can flex. Likewise, in the physics of structures, when a perpendicular force is exerted at the middle of a flexible connector, such as a guy wire, it creates tension (T) that stabilizes the system. These principles are foundational in understanding the behavior of materials under stress.