| Testing Mechanics Corporation utilizes Avongard Crack Monitors (or equivalent) for crack monitoring. The Avongard Crack Monitor is a simple and effective gauge to measure the movement of cracks in brick, concrete, or masonry structures. The Avongard Crack Monitor consists of two overlapping acrylic plates. One plate is white with a black millimeter grid, while the other is transparent with red crosshairs centered over the grid. Once the Crack Monitor is in position across a crack, the cross hairs shift vertically or horizontally on the grid if movement occurs, so that crack movement can be documented. The Avongard crack monitor can identify masonry wall movements down to 0.5mm. Monitors are installed in locations of adjacent structures typically based on the results of the Pre-Construction (Pre-Condition) survey report of the adjacent structures. Photographs are obtained on the day of installation, and the monitors are examined once on a daily basis on days where excavation and/or construction activity is being performed that may produce vibrations or other conditions that may result in building movement. Daily photographic documentation is provided in the final report. If a crack gauge indicates movement of more than 1 millimeter between 2 consecutive readings, or a cumulative movement exceeding 2 millimeters, Testing Mechanics Corporation notifies the on-site supervisor of the construction company, or other designated competent person, of the findings. |
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