Research of the Existing Post - tensioned Roof Trusses and their Reliability

The issue of insufficient reliability and, in some cases, the failure of post - tensioned bridge structures, footbridges, and roof trusses, particularly in industrial halls, is one of the current and serious problems of the construction industry in the Czech Republic. The most well - known failures of these structures include the collapse of the Morandi Bridge near Genoa, Italy, in August 2018, and the collapse of the Troja footbridge in Prague in December 2017. Less known are the failures of post - tensioned truss roof structures that occurred in the Czech Republic and Slovakia. Especially in the Czech Republic, there were failures in Tachov (2010 and 2018), Sluknov (December 2023), and Karlovy Vary (March 2024). A common feature of all these failures was the corrosion of the prestressing reinforcement in inadequately grouted cable ducts. Roof structures of this type have been used in more than 100 buildings that are still in operation in the Czech Republic. In response to this situation, the company Rada Building s.r.o., in cooperation with academic institutions, developed a method to reinforce trusses threatened by corrosion using an external steel structure. The company carries out the reinforcement work during normal operation in the hall below the trusses. Research on post - tensioned truss structures and the possibilities of their static securing is being conducted in cooperation with the Faculty of Civil Engineering at VSB – Technical University of Ostrava, the Faculty of Art and Architecture at the Technical University of Liberec, and the company Rada Building, s.r.o. The ambition of the research is to analyze the condition of as many trusses as possible embedded in buildings in the Czech Republic and Slovakia using building structure diagnostic methods and to evaluate these surveys. Furthermore, the research aims to verify the actual behavior of such structures through tests on real trusses taken from demolished buildings. VSB – TU Ostrava has several trusses available, and load tests are currently being carried out on them. An important and final part of the research is to find the optimal diagnostic method that would improve the ability to predict the risk of roof failures in operational buildings and to optimize the methods for securing these structures to ensure full static reliability with the lowest possible costs and minimal impact on the building.