Method for analysing externally pre-stressed, sheathed cables

摘要

Pre-stressed cables (3) and a hydraulic binding grout (4) are contained in a sheath (2) and used to support concrete art works. Grout abnormalities or cavities containing air or water may lead to cable failure and are detectable by portable equipment (5) which has cylindrical electrodes (11, 12) connected (13, 14) to an oscillator (15). The oscillator produces varying frequencies which depend on the inter electrode capacitance and hence grout condition. <??>An Independent claim is included for equipment which uses the oscillator and electrode method for detecting grout abnormalities.