Experimental study on internal monitoring structure of a new prestressed anchor cable

On account of their difficult internal stress monitoring, a new type of internal stress monitoring structure for pre-stressed anchor cables is developed and then tested by the destructive tension tests and the repeated tension tests under multi-levelload. The test results show that before reaching the yield load, the new monitoring structure deforms synchronously with the anchor cable, representing a relatively high consistency. The residual strain caused by processing of monitoring structure is eliminated by 13 times of repeated tensioning under high loads, thus improving the accuracy. After elimination of the residual strain, a conversion formula is established between strain of monitoring structure and stress of anchor cables. The error of stress of anchor cables measured by this conversion formula is smaller than 2%. This study may provide a new effective and feasible monitoring technology for the internal stress monitoring of pre-stressed anchor cables.