Engineering Commons^™

Experimental And Theoretical Investigation Of Adsorption Of Water Vapor On Carbon Nanotubes, Pyoungchung Kim

Doctoral Dissertations

The adsorption of water in nanoporous materials becomes an important issue in the environmental fate and applications when one considers the practical use of these materials as adsorbents for hazardous organic compounds in the diverse environments.

In this study, the complexity of water-SWNTs interaction was investigated by morphological and chemical characterization techniques, by gravimetric adsorption measurement and by interpretation of experimental adsorption isotherms by fitting to several existing semi-empirical water adsorption models. Commercially available SWNTs samples were measured for chemical and physical characterization such as O% by x-ray photoelectron spectroscopy, I_D/I_G by Raman spectroscopy and surface and …

Structural Health Monitoring And Damage Evaluation Of Full-Scale Bridges Using Triaxial Geophones: Controlled In-Situ Experiments And Finite Element Modeling, William S. Ragland Ii

Doctoral Dissertations

The purpose of this study was to evaluate the effectiveness of various vibration-based damage detection methods using triaxial vibration records obtained using inexpensive geophones during in-situ, full-scale, damaged bridge tests.

Geophones are passive directional sensors and much cheaper than accelerometers which are typically used for structural vibration measurements. However, magnitude and phase errors associated with a geophone’s output must be corrected for if they are implemented in bridge monitoring systems. This research discusses correction procedures for magnitude and phase errors associated with geophones. A simply supported beam was analyzed to verify that the correction procedures and modal parameter identification procedures …

Development Of Dbt Bridge System With Continuous Joints For Accelerated Construction, Lungui Li

Doctoral Dissertations

Speed of construction has become a critical issue to minimize disruption of traffic and commerce. One of the promising systems for accelerated bridge construction is the use of the decked bulb-tee (DBT) girders for the bridge superstructure. An integral deck that is precast and prestressed with the girder provides benefits of rapid construction along with improved structural performance. However, the limited research and concerns about the use of longitudinal joints as well as intermediate diaphragms limit widespread of the DBT bridge system.

This dissertation presents a study of the continuous for both moment and shear transfer longitudinal joint detail and …

Impact Of Larger Diameter Strands On Aashto/Pci Bulb-Tees, Jayaprakash Vadivelu

Masters Theses

This thesis consists of the analytical study and the experimental investigation of larger diameter strands in AASHTO Type I girders. The main purpose of this study was to verify that the 2 inch minimum spacing recommended by ACI 318-08 and AASHTO (2008) can be used for 0.7 inch diameter strands by comparing various effects in girders using 0.7 and 0.6 inch diameter strands. Based on the parametric analysis it was concluded that by using 0.7 inch strands there was a considerable saving in the material. For example, an AASHTO BT-72 with 0.6 inch strand could be replaced with AASHTO BT-54 …

Structural Behavior Of A Pile Framed Tie Back Retaining Wall, Mieah Dee Turner

Masters Theses

The objective of this research study is to analyze the preliminary structural behavior of a pile framed tie back retaining wall concept created by the Tennessee Department of Transportation (TDOT). Instrumentation is used to measure the forces and moments on the steel piles, loads on the anchors, and the pressure and displacement of the retained soil over time. Data collection for steel pile analysis consisted of the comparison of strain gage readings. Stress values were calculated from the readings and reduced down to an axial and bending force along the pile. Soil pressures that built up behind the wall were …

The Influence Of Brick Veneer On Racking Behavior Of Light Frame Wood Shear Walls, Nikola Zisi

Doctoral Dissertations

The racking behavior of an anchored brick veneer – wood frame wall system was investigated analytically. The core wall model simulated a wood frame sheathed with oriented strand board. Brick veneer was then tied to the exterior wall face, and gypsum wallboard sheathing was added on the interior wall face. Two-dimensional linear elastic beam and continuum type elements were used to model these principal wall components. Gap elements were used to prevent sheathing overlap and to model panel bearing at the base. The veneer was supported on compression-only spring elements in the vertical direction and perfectly plastic spring elements in …

Experimental Investigation Of Precast Bridge Deck Joints With U-Bar And Headed Bar Joint Details, Samuel Lewis

Masters Theses

This thesis presents the experimental investigation of two joint details for use in precast bridge deck systems. U-bar and headed bar joint details were developed for use in accelerated construction applications. Both details, in practice, would consist of staggered protruding reinforcement that would allow for the anchorage of the precast deck component into the joint. Six specimens containing the joint details were constructed and tested. Three specimens were tested in flexure to simulate the forces that would be experienced in a longitudinal deck joint, and three specimens were tested in tension to simulate the forces that would be experienced in …