Experimental measurement of the anchorage length of interrupted prestressing reinforcement

article in a collection out of WoS and Scopus

English

This paper focuses on the current problems of breakage of prestressing reinforcement (mostly caused by corrosion) of prestressed precast bridge girders from 1960-1990 and its influence on the residual load-bearing capacity. Actual prestressed precast girders (I-73 structural type), which were developed in 1973 and which were in service from 1979 and 1980, were obtained for the purposes of experimental testing. Researchers from Brno University of Technology designed unique experiments on these girders to determine the actual anchor length of a fully grouted prestressing cable made of 4.5 mm patented wires. Semi-destructive probes were drilled along the length of the prestressing rein-forcement up to the depth of the prestressing reinforcement. Subsequently, optical instruments were inserted into the drilled probes to collect image data, as the transformation of the prestressing reinforcement cannot be determined in any other way in the case of girders of such age. Controlled breaking of the reinforcement was then carried out to simulate corrosion failure of the reinforcement and the condition of the prestressing reinforcement before and after the controlled breaking was recorded by optical instruments in each probe. The image data collection and the subse-quent evaluation of the prestressing cable wires slips was performed in collaboration with X-Sight, a company which focuses on optical applications in industry. The actual anchor length of the fully grouted prestressing reinforcement determined in this way can then be taken into consideration in detailed static calculations of the residual load-bearing capacity of the prestressed bridges.

prestressed girder; anchorage length; existing bridge; prestressing reinforcement; corrosion

SVOBODA, A.; KLUSÁČEK, L.

6. 9. 2022

Technische Akademie Esslingen e. V.

Esslingen

978-3-8169-3549-0

5. Brückenkolloquium