This technology, developed by USF Inventors, uses impedance and magnetic measurements to produce an image of the cross-section of an external post-tensioned tendon in a portable computer. Air voids and other deficiencies in the grout portion between the outer strand bundle envelope and the inner surface of the tendon polymer duct will be flagged. The FTIU contains a magnet with a force sensor and a flexible capacitive plate that follows the tendon duct perimeter during rotation around the tendon. The design is flexible to fit different sizes of bridges as well as the allowance for imaging in tight spaces without interfering with other tendons or structural members.
Field Tendon Imaging Unit Physical Arrangement