Engineering Commons^™

Bond Performance Of High-Capacity Strands In High Strength Concrete, Xin Jiang

Doctoral Dissertations

18-mm-diameter (0.7-in.) strand has the ability to introduce almost twice the prestressing force of 13-mm-diameter (0.5-in.) strand and 135% of the prestressing force of 15-mm-diameter (0.6-in.) strand, which could result in a significant increase in the span capacity of the current AASHTO bulb tee girders without having to modify the sections or acquire new forms. To date, the information regarding the bond performance of 18-mm-diameter (0.7-in.) prestressing strand is very limited, preventing its application despite its attractive high-strength. Also, our understanding of the bond mechanism is incomplete and non-quantitative; a rational understanding of the bond mechanism would help predict the …

Investigation Of Composite Patch Performance Under Low-Velocity Impact Loading, Geoffrey Roy Goodmiller

Masters Theses

Bonded fiber composite repair on damaged metal structures can be an effective method to restore load carrying capacity or increase damage resistance. Low velocity impacts can cause barely visible damage to the interior structure of laminated composites. Delamination between plies is of particular concern in these composites. Impacts may also create disbonds between the patch and metal substrate. A building-block approach was suggested to model impact damage to composite patches. Composite, adhesive, and metal substrate damage models were separately validated and then combined. Cohesive Zone theory modeled interlaminar composite damage and adhesive damage. Hashin failure criteria with energy dissipation based …

An Automated Finite Element Analysis Framework For The Probabilistic Evaluation Of Composite Lamina Properties, Jonathan Phillips Weigand

Masters Theses

This thesis outlines the development of computational modeling tools used to predict the elastic properties of composite lamina from representative volume elements (RVE) using numerical methods. The homogenization approach involves the use of Gauss’s Theorem to simply the average volumetric strain integral into a surface integral containing which is defined by surface displacements and their direction. Simulations of RVEs under specific loading conditions (longitudinal tension or shear and transverse tension or shear) are then performed in the software package ABAQUS to obtain the surface displacements. It was found that obtaining quality meshes and applying periodic boundary conditions for each RVE …

Isolation As A Seismic Design Strategy For Bridges In The New Madrid Seismic Zone, Timothy E. Huff

Doctoral Dissertations

The seismic hazard in the New Madrid Seismic Zone (NMSZ) is primarily from the New Madrid Fault System (NMFS), which produced a series of large earthquakes in 1811-1812. Estimates of the magnitude of these earthquakes and the event magnitude appropriate for structural design in the New Madrid Seismic Zone vary greatly and have been the subject of much debate.

Current bridge design practice in the region relies primarily upon controlled damage by plastic hinging in columns/piles at piers to prevent collapse. Abutments are typically modeled with linear springs to represent piles and backfill stiffness. The usefulness, after a major seismic …

Structural Health Monitoring And Damage Identification Of Bridges Using Triaxial Geophones And Time Series Analysis, Reza Vasheghani Farahani

Doctoral Dissertations

This study uses the vibration data of two full-scale bridges, subjected to controlled damage, along the I-40 west, near downtown Knoxville, TN, to evaluate the feasibility of time series-based damage identification techniques for structural health monitoring. The vibration data was acquired for the entrance ramp to James White Parkway from I-40 westbound, and the I-40 westbound bridge over 4th Avenue, before the bridges were demolished during I-40 expansion project called Smartfix40. The vibration data was recorded using an array of triaxial geophones, highly sensitive sensors to record vibrations, in healthy and damaged conditions of the bridges. The vibration data is …

Rule High School Athletic Field Renovation, Nathan W. Foust

Chancellor’s Honors Program Projects

No abstract provided.