Performance Evaluation on Core Wire of Smart Strand for PSC Structures

Abstract : The Korea Institute of Construction Technology is undertaking the development of the smart strand for PSC structures enabling to measure the prestress force all along its service life since the completion of construction. Apart from such measurement function, the smart strand shall at first satisfy the structural performance required as a tendon. Therefore, research has been implemented so as to embed the sensor within the small diameter of the core wire by using optical fibre sensor. To that goal, new materials were devised for the core wire to avoid the method cutting and machining the conventional steel core wire. The performances of the core wire fabricated by this new approach as well as its fabricability and structural performance were examined through tensile test to derive the optimal fabrication method of the smart strand. The tests conducted on the core wire fabricated by the so-selected fabrication method and embedded with the optical fibre sensor revealed that the resulting strain measurement range was significantly larger than the range complying with the design prestress force of the conventional steel strand. The core wire for the smart strand under development was seen to provide sufficient measurement performance as well as to satisfy the required structural performance. Accordingly, the newly developed core wire can be conveniently applied in the conventional steel strand.