NASCLA Accredited Practice Exam

Stirrups are commonly placed more closely near the support of a beam due to the unique stresses that occur in that area. In a beam, the support regions experience higher shear forces and moments, which require additional reinforcement to effectively manage these forces. By spacing stirrups more closely at the supports, the design helps prevent shear failure and ensures that the beam can transfer the loads properly.

This close spacing allows for better confinement of the concrete within the tension zone, which is crucial for maintaining the beam's integrity under load. The design practice acknowledges that the maximum shear stress typically occurs near the supports, making it essential to provide adequate reinforcement in these critical areas.

Other placement strategies, such as putting stirrups far apart across the entire length or only at the mid-span, would not adequately address the shear stresses present at the supports. Additionally, equal spacing may not provide the necessary support where it is most needed, leading to potential structural weaknesses. Hence, placing stirrups more closely near the supports is a best practice in structural engineering.