An Experimental Study on the Development an Embedded Post-Tensioning Anchorage Device for 2,360 MPa Strand

High-rise concrete walls such as the cylindrical outer structure of LNG storage tanks are prestressed with high strength prestressing tendons horizontally and vertically. Due to the limitation of space in the lower part of the wall, a U-shaped vertical tendon profile is typically used where all the anchorage devices are installed on the top of the wall. However, this produces excessive frictional loss in prestressing, and the relatively longer work at height can cause safety issues. To overcome these weaknesses, a vertically embedded post-tensioning system in the lower part of the wall was developed by VSL for 1,860 MPa strand. In this study, an experimental study was conducted to develop a vertically embedded post-tensioning anchorage device for 2,360 MPa ultra high-strength strand. The performance evaluation method of the embedded post-tensioning anchorage device is introduced, and performance tests were performed on 6 specimens with various parameters. In the performance testing, there was no breakage or pulling out of the strand until the maximum load was introduced, and the sucked in displacement of the grout inside the casting was found to be within a stable range. These results confirmed that the embedded post-tensioning anchorage device for 2,360 MPa-class strand could be commercialized.