What is the first step in constructing a concrete frame building?

The first step in constructing a concrete frame building is to build the formwork. This process involves creating molds that will hold the concrete in place until it sets and cures. Formwork is essential for achieving the desired shape, dimensions, and surface finish of the concrete elements, such as columns, beams, and slabs.

Building the formwork typically comes before any concrete is poured, as it provides the necessary structure to contain the liquid concrete and shapes it to the architectural specifications of the building. Once the formwork is securely in place and checked for accuracy, the next step would be to place steel reinforcement within the mold to provide added strength and stability to the concrete once it hardens.

Thus, establishing the formwork first is critical as it sets the foundation for all subsequent construction activities in the concrete frame construction process. Other choices represent actions that occur later in the progression of building a concrete frame structure.