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...
Crack and structural response to construction trench blasting was measured in a woodframe house with a stucco exterior. Blasts at distances between 232 m to 368 m produced peak particle velocities (PPV) and air blast over pressures (AB) of 9 mm/sec and 0.02 kPa (123 dB), respectively. Structural response velocities...
In early 2001, a sinkhole formed directly under State Road 66 near the city of Sebring in Highlands County, Florida. The Florida DOT built a land bridge over the sinkhole and the road was reopened to traffic. Since SR-66 is an important regional trucking route, it was decided that the...
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,...
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...
This appendix synthesizes micrometer changes in crack width in response to both long term (environmental) and transient (blast vibration) of four of the structures in the main body. The appendix begins with a description of the genesis of the study and instruments employed. Response of the distressed wood-framed structure in...
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...
Construction is omnipresent in modern-day America. It's the sound and vibration of a nation scrambling to keep up with its burgeoning population. In most states, allowable construction-induced ground motions range from 0.5 to 1.0 inches per second (in/sec) and under certain
conditions up to 2.0 in/sec.
However, ground motion as...
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...
This paper describes qualification of devices to measure sub micro-meter changes in crack width, which is the basis of autonomous crack monitoring for control of blasting vibrations. Performance of LVDT, eddy current and potentiometer sensors to monitor long-term and transient displacements will be described. Potentiometers are attractive for wireless measurement,...
This file contains power-point slides of Application to Crossbow’s Smart Dust Challenge Contest, title "Wireless Data Acquisition System" by Mat Kotowsky and Hasan Ozer. The presentation was delivered at University of California, Berkeley on February 11, 2005.
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...
Northwestern University developed copper-precipitation-hardened, high-performance weathering steel (NUCu 70W Steel) that is produced by hot rolling after casting and then air-cooling. Due to simple processing the steel is fabricated at lower cost than competing high-performance steels that require quench and tempering. NUCu 70W steel can be easily welded without pre-...
During the past several years an easily weldable, high strength (more than 75 ksi yield), high impact fracture toughness steel (NUCu steel) has been investigated at Northwestern University with bridge applications in mind. For good weldability without pre-heating and post-heating, the carbon content of the steel was kept low and...
This presentation provides information on the the project "Use Of High-Performance A710 Grade B Steel in Construction of Lake Villa, IL Bridge". The presentation was delivered by Morris E. Fine, Semyon Vaynman, and Nunzio Mario Biondolillo on June 14, 2006.
This paper describes developments of integrated tools for predicting, monitoring, and controlling ground movements associated with excavations in urban areas. Successful use of monitoring data to update performance predictions of supported excavations depends equally on reasonable numerical simulations of performance, the type of monitoring data used as observations, and the...
Two numerical procedures are described that quantitatively identify a set of constitutive parameters that best represents observed ground movement data associated with a deep excavations in urban environments. This inverse problem is solved by minimizing an objective (or error) function of the weighted least-squares type that contains the difference between...
Successful use of monitoring data to update performance predictions of supported excavations depends equally on reasonable numerical simulations of performance, the type of monitoring data used as observations, and the inverse analysis techniques used to minimize the difference between predictions and observed performance. This paper summarizes each of these factors...