Engineering Commons^™

Post-Seismic Response And Repair Of Earthquake-Damaged Reinforced Concrete Bridges, Giacomo Fraioli

Doctoral Dissertations

“In bridge structures, column members are typically designed to be the primary source of energy dissipation during an earthquake. Therefore, reinforced concrete (RC) bridges that are damaged in an earthquake tend to have damage to the column members. While many studies have been conducted on seismic strengthening of RC bridge columns, most are focused on retrofit instead of repair. In addition, the limited research on seismic repair of RC bridges has focused on evaluating the response of individual columns (member level), not the bridge structure (system level), due to limitations in modeling and especially testing of full bridge structures. Local …

Innovative Approach To Use Guayule Resin As A Bio-Based Asphalt Alternative, Ahmed Hemida

Doctoral Dissertations

"Asphalt cement will not last long as the world encounters a diminishment in crude oil. Novel resources can contribute to replacing asphalt with the sustainable, flexible pavement. This study presented guayule resin (guayule) as an innovative bio-based asphalt alternative. Ground tire rubber was used as an asphalt enhancer. To judge the guayule's contribution, guayule-based binders were investigated and compared to control asphalt and asphalt-rubber binders. Binders were assessed according to comprehensive Superpave criteria and advanced rheological tests. Component analysis was performed to link the microscale level with the macroscale level. To validate the novel binder, satisfying mix performance tests were …

Behavior Of Negative Stiffness Metamaterial Systems In Structural Engineering Applications, Yasser Darwish

Doctoral Dissertations

“Metamaterial systems with negative stiffness behavior became a point of interest in many energy dissipation applications due to their ability to dissipate high levels of energy. Negative stiffness metamaterial elements can dissipate energy through non-linear elastic behavior when transferred from one stable mode of buckling to another. Hence, the ability of such elements to be reusable for multiple loading cycles exists. Such unique properties made the metamaterial systems a perfect candidate for structural applications such as impact protection of bridges against collision. This research provides innovative metamaterial shell structure that can exhibit negative stiffness behavior by deforming from one shape …

Design And Performance Of Fiber-Reinforced Concrete With Adapted Rheology For Construction And Repair Of Bridge Structures, Ahmed Abdelrazik

Doctoral Dissertations

“The objective of this document is to design high-performance fiber-reinforced self-consolidating concrete (FR-SCC) for infrastructure repair and fiber-reinforced super-workable concrete (FR-SWC) for bridge construction. The investigated fibers included propylene synthetic fibers, hooked steel fibers, double and triple hooked steel fibers, hybrid crimped steel fiber and polypropylene multifilament fibers, and micro-macro steel fibers. The fiber volume varied between 0 and 0.75%. An expansive agent (EA) was incorporated to compensate for shrinkage and induce compression in the concrete at early age. Two types of EA (G and K) were employed at 0 to 8%, by mass of binder. The investigated FRSCC and …

Long Period Fiber Grating, Thin Coating Of Graphene And Silver Nanowires, And Corrosion Sensing For Life-Cycle Assessment Of Steel Structures, Chuanrui Guo

Doctoral Dissertations

"This study aims to develop and validate a compact, integrated lab-on-sensor system for simultaneous measurement of strain, temperature and corrosion-induced mass loss in steel structures and concrete reinforcement elements in order to assess their life-cycle performance. The sensing system operates based on the principle of long period fiber gratings (LPFG) that are responsive to both thermal and mechanical deformation, and the change in refractive index of any medium surrounding the optical fiber. To fabricate a LPFG sensor for strain and temperature measurement, a CO₂ laser aided fiber grating system was assembled. To enable mass loss measurement, a low pressure …

Critical Buckling And Post-Buckling Behavior Of Thin-Walled Liners Encased By Underground Pipelines In Saturated Soils, Zhaochao Li

Doctoral Dissertations

"This study aims to investigate the structural stability of thin-walled liners encased in functionally-obsolete underground pipelines in saturated soil under external hydrostatic pressure, a concentrated load, temperature change or their combination, and develop a simplified circular arch model of thin-walled liners when not constrained by the pipelines. The friction and adhesion on the interface between a liner and its constraining surface (pipeline or grouting), and the pressure gradient on deeply-buried pipelines are neglected. The critical buckling load of elastic liners is analytically derived under a plane strain condition using the principle of minimum potential energy. The analytical solution is either …

Web Crippling Strength And A Combination Of Bending And Web Crippling Of Cold-Formed Steel Beams, Nipon Hetrakul

Doctoral Dissertations

"The web crippling strength of cold-formed steel beams was investigated experimentally. In this investigation, due consideration was given to the possible influence of bending moment and shear force on the web-crippling loads.

For the subject of web crippling strength, the study involved the testing of 140 built-up beams having single unreinforced webs and 152 I-beams having double webs. In addition, 66 beam tests were conducted for the case of combined bending moment, shear and web crippling.

The experimental results obtained from the beam tests conducted at the University of Missouri-Rolla and the early tests performed previously at Cornell University were …