Preliminary Study on the Length Prediction of Prestressed Strands by Impact Responses

• Main Authors: Ya-Ling Li, 李雅玲
• Other Authors: Chin-Peng Yu
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/73645932294577277158

碩士 === 朝陽科技大學 === 營建工程系碩士班 === 98 === Ground anchor is a common facility used in strengthening slope stability. The anchored length normally remains unknown after erection since the anchor is buried and can not be inspected. However, the total length of an anchor strand is normally a controlled value, it is then possible to recover the anchorage length by evaluating the unbonded segment through certain non-destructive testing techniques. With the anchorage information being recovered, the anchor strength can thus be assessed accordingly. This study proposed a back-computing formula, derived from 1-D member theory, for the prediction of strand length from natural frequencies. Such formula was compared with the well-known cable formula in the prediction of lengths of prestressed strands. The proposed formula is superior to the cable formula since the former can be applied without knowing the level of axial forces and boundary conditions while the later requires axial force being a given parameter. The preliminary applications of the proposed formula to the determination of lengths of very thin steel wires and prestressed concrete poles indicate that the proposed formula can be a potentially useful tool yet further modifications in the analysis process are still in demand.