What is usually placed to stop at the underside of the lowest supported beam or girder in the floor above?

• A. Concrete for Columns
• B. Masonry Blocks
• C. Reinforcing Steel
• D. Gravel Layer

Answer: (A)

When pouring vertical structural members in a multi-story concrete frame, the concrete for the column is brought up to the level where the floor above will rest on the column. It is then stopped at the underside of the lowest supported beam or girder. This ensures a solid bearing surface and a proper connection between the column and the beam, allowing the floor loads to transfer smoothly down into the column and ultimately to the foundation. Stopping at that level also helps avoid misalignment or interference with the beam’s seat or with any cap details that may be required.

Masonry blocks would not be the stop point for a column pour, since they’re used for walls rather than vertical structural pours. Reinforcing steel is embedded within the concrete and defines the reinforcement, not the stop height. A gravel layer is a base or drainage feature, not a bearing stop for a column pour.