Autonomous Crack Comparometer Phase IIPublic Deposited
The thesis describes the second phase of development of the Autonomous Crack Comparometer (ACC) system to incorporate measurements of ground motions and add several changes in the autonomous operation. In order to obtain the ground motion and air blast data, four additional transducers have been added. There are now a total of ten channels of data autonomously collected and comparatively displayed by ACC. The web page has been fully developed and now dynamic blast effects are compared with longterm effects. Data are password protected. Finally, new data acquisition system software has been installed that allows direct modem communication. The ACC installed in this second test house allowed measurements, which verified past experience that daily and weekly weather related crack displacements are greater than those produced by dynamic events, whether they are household activities or blasts. Frontal (weekly) weather changes produce the greatest crack response. Five different crack displacement sensors were evaluated to determine the magnitude of thermal hysteresis and long-term electronic drift. The eddy current sensor (9000 series) and the LVDT sensor were found to be acceptable to measure micrometer displacements.
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