Transmission length of prestressing 7ϕ5 mm strand in axially prestressed high performance concrete members / Andrzej Seruga, Marcin Dyba // W: Bond in Concrete : Bond, Anchorage, Detailing : 5th International ... więcej

Transmission length of prestressing 7ϕ5 mm strand in axially prestressed high performance concrete members / Andrzej Seruga, Marcin Dyba // W: Bond in Concrete : Bond, Anchorage, Detailing : 5th International Conference, Stuttgart, Germany, 25th - 27th July 2022 : proceedings [Dokument elektroniczny] / eds. Jan Hofmann, Giovanni Plizzari. – Stuttgart : Institute of Construction Materials. University of Stuttgart : Materials Testing Institute. University of Stuttgart, 2022. – S. 567-578 : fot., rys., tab., wykr. – Tryb dostępu: https://d-nb.info/1264911548/34. – Bibliogr. 16 poz., Abstr.

An extensive effort has been realized to develop applicable techniques for investigating the transmission length of prestressing force in pretensioned concrete members. The current design codes specify ... więcej

An extensive effort has been realized to develop applicable techniques for investigating the transmission length of prestressing force in pretensioned concrete members. The current design codes specify equations to calculate analytically its value. The exact value depends on lot of factors. The most important are strictly connected with type of concrete. For members precasted of high-strength and high-performance concrete (HPC) there are no standardized provisions for designing. Number of publications is also limited. For these reasons in 2012 year in Cracow University of Technology started research program including the experimental determining of transmission length in axially prestressed concrete members made of HPC. The value of 200 kN of prestressing force was designed. Tensioning force release as well as tests were performed for concrete maturity of 24 and 72 hours. Experimental tests included: continuous data registration of tensionig force, measurement of concrete strains along the strand axis on the concrete surface before detensioning, just after and time dependent. Based on the executed measurements of concrete strains in the longitudinal direction, the transmission length was calculated according to the 95% of average maximum strain (AMS) method. The development of concrete strains over time and its influence for the transmission length was also analyzed. The transmission length calculated according to the proposed procedure in which the increment difference of the concrete longitudinal strain, measured on the external beam surface starting from the end of the precast element to the average maximal concrete strains are taken into consideration, should be recommended to practical application.