A focus on how the building structure is designed must be done early on during the conceptual and schematic design phases. It will set the tone for how the building will be constructed. For example, consideration of an efficient concrete formwork system will result in a speedy core construction. Conversely, disregard to constructability will require considerable redesign around randomly placed walls or columns. Structural efficiency requires thoughtful consideration of what to build and how to build. The most appropriate building materials such as concrete, steel, masonry and wood must be selected. Means and methods such as detailing, formwork and construction sequencing used to assemble them into a structure must be clearly understood.

Hilton Grand Vacation Club, 26-story time share tower located on the Las Vegas Strip, completed in 2003 features 15,000 sf post-tensioned concrete floor plates. Architect: MBH Architects, Newport Beach, Calif., Contractor: Penta Building group, Las Vegas

The post-tensioning method addresses both sides of the efficiency coin. Its use can significantly reduce the amount of rebar and concrete as well as shorten construction schedule of a project. Construction crews can pour a post-tensioned floor in one or two days, compared to three or four days required for their rebar-only counterparts. Additionally, it allows for greater freedom in building layout by incorporating larger spans; controlling long-term deflection; allowing for the use of shallow framing members and lighter foundations; reducing floor-to-floor height; and decreasing seismic demand due to lower seismic mass; most of which positively affects architectural and mechanical systems. Exterior skin quantities are reduced resulting in less overall building volume to heat and cool.