The efficient use of pultruded carbon fibre reinforced plastic profiles (CFRP-tendons) to prestress high performance concrete (HPC) highly depends on the performance of the anchorage system and on the material choice. The current applications only utilized approx. 40 % of the CFRP material strength in prestressed concrete elements. A higher prestress implicates lower costs of fully prestressed concrete elements. The aim of the present project was a design optimization of the pretensioning anchorage system, which has to be removable and reusable. The optimized design was achieved by means of finite element (FE) calculations, where parametric studies were complemented with extensive experimental work for validation.
The analytical results showed a reduction of up to 25% for the relevant stress peaks in the tendons. The static rupture load under laboratory conditions increased by 24%, and the pretensioning level on-site could even be increased by 50%. This improvement in production efficiency can be explained with the easier applicability of the new system (i.e. failure tolerant assembly and prestressing process).