Experimental Time Domain Reflectometry (TDR) data obtained from the field are compared with numerical simulations using a finite-difference solution of the transmission line equations. The model simulates transmission of a voltage pulse along a lossy coaxial cable where deformities on the cable, such as crimps and shears, are represented by...
This thesis combines field and laboratory measurements with three dimensional (3D) finite element analysis (FEM) to demonstrate the use of Time Domain Reflectometry (TDR) cable-grout composites to measure localized shearing in soft soil. Past field installations of TDR cable-grout composites in rock have lead to its widespread use in the...
This thesis presents the application of Time Domain Reflectometry technology in nine case studies. Presented in detail are cable and grout installation techniques, data acquisition instrumentation and autonomous real time monitoring of soil deformation using TDR. The goal of this work is to summarize the state of the technology in...
Miniaturized, wireless instrumentation is now a reality and this thesis describes development of such a system to monitor crack response. Comparison of environmental (long-term) and blast-induced (dynamic) crack width changes in residential structures has lead to a new approach to monitoring and controlling construction vibrations. In wireless systems transducer power...
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,...