When bars are placed at the top of a beam, taking the place of some concrete, what restrains them?

When bars are placed at the top of a beam, taking the place of some concrete, what restrains them?

• A. Stirrup-Ties
• B. Tie wires only
• C. Bearing pads
• D. Anchor bolts

Answer: (A)

When some concrete is replaced by top reinforcement in a beam, those top bars have less concrete around them to resist lateral movement. The transverse reinforcement provided by stirrup-ties wraps around the longitudinal bars, giving them confinement and preventing buckling or displacement. This ties the top bars into the rest of the section, helping them stay in place during pouring and service and enhancing shear and overall stiffness in the compression zone. Tie wires alone aren’t continuous confinement, and bearing pads or anchor bolts aren’t used to restrain the top bars in this way, so stirrup-ties are the correct restraint.

When some concrete is replaced by top reinforcement in a beam, those top bars have less concrete around them to resist lateral movement. The transverse reinforcement provided by stirrup-ties wraps around the longitudinal bars, giving them confinement and preventing buckling or displacement. This ties the top bars into the rest of the section, helping them stay in place during pouring and service and enhancing shear and overall stiffness in the compression zone. Tie wires alone aren’t continuous confinement, and bearing pads or anchor bolts aren’t used to restrain the top bars in this way, so stirrup-ties are the correct restraint.