The recent changes to the ASTM E-119 standard now make it possible to obtain exposed structural steel members that have a fire resistance of up to 4 hours. Concerning wood, the new 2018 National Design Specification now allows for mass timber slabs to be left exposed without any additional fire protection for up to two hours. These recent changes now make it possible to leave steel and wood structures completely exposed while providing a safe environment for a building’s occupants.
Minimizing the floor-to-floor height in high-rise buildings has always been an objective for the design community. Every inch saved on each floor of a skyscraper has a huge impact on the overall cost of a building. For the last few decades, the only system capable of really maximizing the floor-to-floor height in high-rise construction was post-tensioned concrete structures. In recent years, several new floor assemblies combining shallow composite beams and long-span slab elements have emerged to offer prefabricated slim floor systems for the first time.
Different combinations of composite structures are already in use around the globe and offer a foundation to demonstrate how these systems could be used in the future to make taller, safer and more sustainable buildings.