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Full-Text Articles in Civil Engineering

Characterize Behavior Of Geogrid Reinforced Ballast At Different Levels Of Degradation Through Triaxial Shear Strength Test And Discrete Element Modeling, Yu Qian, Debakanta Mishra, Erol Tutumluer, Hasan A. Kazmee Oct 2015

Characterize Behavior Of Geogrid Reinforced Ballast At Different Levels Of Degradation Through Triaxial Shear Strength Test And Discrete Element Modeling, Yu Qian, Debakanta Mishra, Erol Tutumluer, Hasan A. Kazmee

Civil Engineering Faculty Publications and Presentations

Recent research efforts at the University of Illinois have aimed at studying geogrid applications in railroad track structures, specifically focusing on ballast and subballast reinforcement. Ballast, typically comprising large sized aggregate particles with uniform gradation, is an essential layer in the railroad track substructure to facilitate load distribution and drainage. The primary mechanism of load transfer within the ballast layer involves inter-particle contact between ballast particles. Similarly, the effectiveness of ballast reinforcement with geogrids is primarily governed by the geogrid-aggregate interlock. Such interaction and the effectiveness thereof can change significantly as the level of grain size and shape degradation or …


Stethoscope-Based Detection Of Detorqued Bolts Using Impact-Induced Acoustic Emissions, Joe Guarino, Robert Hamilton Jan 2015

Stethoscope-Based Detection Of Detorqued Bolts Using Impact-Induced Acoustic Emissions, Joe Guarino, Robert Hamilton

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Results of a preliminary study investigating a simple method for detecting looseness in bolted fasteners of a steel structure are presented. Extensive research by many investigators demonstrates that the frequency response of a bolted structural member changes when one or more bolts are loosened. A simple and effective method for detecting looseness can be applied to bolted joints, using inexpensive and commonly-available equipment and software. The difference between spectrograms associated with tight and loose bolts is clearly apparent due to the presence of a tell-tale mode when one or more bolts are loosened. Further, a striking difference can be elucidated …


Uncertainty Considerations In Calibration And Validation Of Hydrologic And Water Quality Models, J. Hernandez Jan 2015

Uncertainty Considerations In Calibration And Validation Of Hydrologic And Water Quality Models, J. Hernandez

Civil Engineering Faculty Publications and Presentations

Hydrologic and water quality models (HWQMs) are increasingly used to support decisions on various environmental issues and policy directions for present and future scenarios, at scales varying from watershed to continental levels. Uncertainty associated with such models may affect the ability of the models to accurately evaluate the response of complex systems, leading to misguided assessments and risk management decisions. Current well-known HWQMs contain numerous input parameters, many of which are not known with certainty, and in other cases model users can hardly recognize the genesis of uncertainty. Uncertainty in data, model structure, and model parameters can propagate throughout model …


Performance Evaluations Of Pavement Working Platforms Constructed With Large-Sized Unconventional Aggregates, Hasan Kazmee, Erol Tutumluer, Debakanta Mishra Jan 2015

Performance Evaluations Of Pavement Working Platforms Constructed With Large-Sized Unconventional Aggregates, Hasan Kazmee, Erol Tutumluer, Debakanta Mishra

Civil Engineering Faculty Publications and Presentations

With recent focus on sustainable construction practices and the ever-increasing transportation cost and scarcity of natural resources, use of unconventional aggregate materials, such as primary crusher run and concrete demolition waste, have become viable for the construction of pavement working platforms over very weak and often wet subgrade soils. To this end, a research study was undertaken at the Illinois Center for Transportation to evaluate the adequacy and field performances of such large-sized aggregate materials and validate new material specifications. A state-of-the-art image analysis technique was utilized to characterize the size and morphological properties, e.g. shape, texture and angularity of …


Flowability And Density Characteristics Of Controlled Low Strength Material (Clsm) Using Native High Plasticity Clay, Anand J. Puppala, Bhaskar Chittoori, Anil Raavi Jan 2015

Flowability And Density Characteristics Of Controlled Low Strength Material (Clsm) Using Native High Plasticity Clay, Anand J. Puppala, Bhaskar Chittoori, Anil Raavi

Civil Engineering Faculty Publications and Presentations

In pipeline construction projects when high plastic clayey soils are encountered in the excavated trench material, they are typically landfilled and better quality materials are imported from outside quarry sources for use as bedding and haunch zone materials. This practice has detrimental environmental and cost impacts; therefore, an efficient reutilization of this high plastic excavated material to produce controlled low strength materials (CLSMs) to use as bedding and haunch zone materials will have major sustainability benefits. As a part of an on-going research study, novel CLSM mix designs were developed by utilizing native high plastic clayey soils from the excavated …