Public concern over construction vibration-induced cracking has led to the development of a radically new approach to vibration, an autonomous crack comparometer (ACC). This thesis chronicles the first step of developing equipment and software necessary for this system. The new system will automatically compare longterm weather induced micrometer changes in...
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...
This thesis consists of the data and analysis of structural responses for two different studies: the Office of Surface Mining (OSM) study of the velocity response of “atypical” residential structures and the Autonomous Crack Monitoring (ACM) study. The main basis of this thesis was to do additional analysis on a...
Autonomous Crack Measurement (ACM) facilitates simultaneous measurement of crack response to environmental changes and vibrations produced by various construction activities. Dual-purpose crack displacement sensors measure crack response, while the vibration environment is defined by standard seismological transducers and the weather environment is defined as changes in temperature and humidity. This...
All structures have cosmetic cracks, which have no influence on structural integrity and usually remain unremarked until the structure’s occupants sense ground vibrations. Such vibrations are often associated with engineering activity, but are rarely responsible for cracks. However, this is difficult to prove without scientific basis. Automated Crack Monitoring (ACM)...
Cosmetic cracks are very common in structures, and most of the time they remain unnoticed and do not decrease the structural integrity. Although these cracks are unremarkable and barely noticeable, occupants become concerned about these cracks when construction occurs nearby. In order to investigate the true nature of these cracks,...
This thesis summarizes two further developments of the Autonomous Crack Monitoring (ACM) system, which facilitates simultaneous measurement of crack response to environmental changes and various dynamic events. The first component was measurement of crack responses in three different materials and locations in a residential structure subjected to ground vibrations produced...
This thesis summarized the qualification and testing of two commercial Autonomous Crack Monitoring (ACM) systems for use in measuring micrometer displacement of cracks. Qualification involved the assessment of both laboratory and field performance in a residential structure subjected to nearby quarry blasting for the production of roadway aggregate. Aggregate and...
Autonomous Crack Monitoring (ACM) and Autonomous Crack Propagation Sensing (ACPS) are two types of structural health monitoring in which characteristics of cracks are recorded over long periods of time. ACM seeks to correlate changes in widths of cosmetic cracks in structures to nearby blasting or construction vibration activity for the...