What is a tie and a spacer in reinforced concrete detailing?

• A. Ties hold stirrups and spacers separate concrete cover.
• B. Ties hold stirrups and transverse reinforcement; spacers maintain minimum concrete cover and rebar separation.
• C. Spacers connect to formwork.
• D. They are decorative.

Answer: (B)

In reinforced concrete detailing, understanding how reinforcement is positioned is essential for durability and strength. A tie’s job is to hold the stirrups and transverse reinforcement in their correct positions so they stay together as a unit during pouring and curing. Spacers, meanwhile, keep the reinforcing bars at the required distance from each other and from the outer surface, preserving minimum concrete cover and preventing bars from touching the formwork or crowding. This combination ensures proper concrete flow around the bars and a reliable bond between steel and concrete. So, tying keeps the reinforcement aligned, while spacers maintain the necessary clearance, which is why this description fits best. Decorations or connections to formwork are not the role of spacers, and they don’t serve a decorative purpose.