Post-tensioned building systems are popular with designers as they allow long spans. This trend brings new challenges in the design of structures for fire safety. In addition to the complexity of these building systems, fires behave differently in large spaces than they do in small rooms. The severity and size of fires affects the structural response of exposed structures. To ensure safety in a cost-effective manner, fire design guidance appropriate to these building systems is required. This proposed research program will investigate post-tensioned building systems typically used for long spans (concrete, timber) under various heating scenarios. These systems have seen limited research attention for their structural performance in fire. The overarching objective of this research is to develop an understanding of the structural performance of post-tensioned structures in fire, with the ultimate aim of discovering how real fires impact whole post-tensioned buildings. Given the high cost of testing whole buildings in fire, numerical modelling tools are essential. There is a need for experimental data to support numerical efforts. This research program therefore seeks to meet the following objectives:(1) create a novel semi-active feedback heating system capable of heating long-span building systems following a well-defined fire exposure; (2) explore and understand the fundamental mechanisms of these building systems under a variety of fire scenarios; and (3) develop validated modelling technologies to describe the response of these building systems to fire. This research program will train 7 graduate and 5 undergraduate highly qualified personnel to apply the research findings to meet society's fire protection requirements. There has been a dearth of activity considering how post-tensioned building systems respond to realistic fire conditions. Test equipment, experimental data, and novel insights into fire-induced structural performance will be obtained to address this knowledge gap. This will help global communities of engineers, architects, and practitioners develop objective and performance-based fire design methodologies. Our national community will benefit, as some building systems considered in this program have not commonly been applied in Canada. This research will develop suitable knowledge and recommendations for the implementation of innovative building systems.**