Polymer and Organic Materials Commons^™

Higher-Order Effects In Biaxial Flexure Of Gfrp I-Section Beams, Zia Razzaq, Faridoon Z. Razzaq

Civil & Environmental Engineering Faculty Publications

A theoretical study of Glass Fiber Reinforced Polymer (GFRP) beams subjected to biaxial bending moments is presented with a focus on the influence of higher-order effects on maximum normal stresses. It is shown that the biaxial bending type of loading causes a dramatic increase in the maximum normal stress for a GFRP beam when induced torsional effects are included. The study demonstrates that the traditional first-order theory can grossly underestimate the maximum normal stress in a GFRP beam. Based on the numerical results presented using a higher-order theory which also accounts for induced warping normal stresses, the maximum normal stress …

Elastoplastic Quasi-Static And Impact Load Response Of Steel Structure Sub-Assemblage With Cfrp Strips, Ali Al Aloosi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

Presented in this paper is the outcome of an experimental investigation of the elastoplastic quasi-static and impact load response of a steel sub-assemblage constructed using a pair of hollow square section members with or without Carbon Fiber Reinforced Polymer (CFRP) strips. The sub-assemblage consists of a long structural member welded to a short member, thus representing a typical combination of a column and a beam on the face of a multi-story steel building frame. The column is subjected to a lateral quasi-static or impact load. Tests are conducted on four separate steel sub-assemblages. The first two tests are conducted with …

Lateral-Torsional Instability And Biaxial Bending Of Imperfect Frp I-Beams, Jodi Knorowski, Stella B. Bondi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

This paper presents the outcome of a theoretical and experimental study of the behavior of Fiber Reinforced Polymer (FRP) I-beams exposed to lateral-torsional instability or when subjected to biaxial bending. Laboratory experiments involved the application of vertical and horizontal static loads to a 4 x 4 x ¼ in. I-beam with various lengths and the resulting deflections were recorded. Governing biaxial flexure and torsion differential equations were modified to account for the presence of initial imperfections and subsequently solved using a central finite-difference scheme. The theoretical predictions of the beam behavior were found to be in good agreement with what …

Electrospinning Processing Techniques For The Manufacturing Of Composite Dielectric Elastomer Fibers, Rani Elhajjar

Civil and Environmental Engineering Faculty Articles

Dielectric elastomers (DE) are novel composite architectures capable of large actuation strains and the ability to be formed into a variety of actuator configurations. However, the high voltage requirement of DE actuators limits their applications for a variety of applications. Fiber actuators composed of DE fibers are particularly attractive as they can be formed into artificial muscle architectures. The interest in manufacturing micro or nanoscale DE fibers is increasing due to the possible applications in tissue engineering, filtration, drug delivery, catalysis, protective textiles, and sensors. Drawing, self-assembly, template-direct synthesis, and electrospinning processing have been explored to manufacture these fibers. Electrospinning …

Experimental Investigation Of The Performance Of A Hybrid Self-Healing System In Porous Asphalt Under Fatigue Loadings, Shi Xu, Liu Xueyan, Amir Tabakovic, Erik Schlangen

Articles

Self-healing asphalt, which is designed to achieve autonomic damage repair in asphalt pavement, offers a great life-extension prospect and therefore not only reduces pavement maintenance costs but also saves energy and reduces CO2 emissions. The combined asphalt self-healing system, incorporating both encapsulated rejuvenator and induction heating, can heal cracks with melted binder and aged binder rejuvenation, and the synergistic effect of the two technologies shows significant advantages in healing efficiency over the single self-healing method. This study explores the fatigue life extension prospect of the combined healing system in porous asphalt. To this aim, porous asphalt (PA) test specimens with …

Strengthening Of Corroded Steel Structures Using Cfrp – An Experimental Review, Ghada El-Mahdy Ph.D., P.Eng, Abdallah H. Yassin, Abdel El Rahman Khaled

Civil Engineering

Fibre reinforced polymers (FRP) have been widely used to strengthen reinforced concrete structures, however, nowadays their use to strengthen steel structures is under investigation. In particular, the need to strengthen corroded steel structures found in aggressive environments, such as marine environments, which have undergone a reduction in cross-sectional area and hence a reduction in their load-carrying capacity is in need of studying. The main problems that arise when using carbon fibre reinforced polymer (CFRP) sheets to strengthen steel structures is the weakness in the interfacial bond between the CFRP and the steel surface, the thinness of CFRP sheet, and the …

Biopolymer-Stabilized Earth Materials For Resilient And Adaptable Infrastructures, Sherif Abdelaziz, Dilip Gersappe, Dilip Rafailovich

Department of Civil Engineering Faculty Publications

Earth dams and levees are constructed and retrofitted nowadays using the same materials that were used in the past, clays and sands. Despite the current advances in engineering, designing and constructing these critical infrastructure, earthen dams and levees continue to suffer from the same challenges over the years. These challenges include internal and surface erosions, loss of stability due to moisture migration, and inabilities to self-heal potential failure points. This project focuses on the use of biopolymers as additives to strengthen earthen dams and levees targeting an overall increase in their resilience.

Explicitly, the report for Milestone 3 presented the …

Molecular Dynamics Modeling And Simulation Of Bitumen Chemical Aging, Farshad Fallah

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Chemical aging of asphalt binder leads to significant changes in its mechanical and rheological properties, resulting in poor pavement behavior and distress. Various laboratory methods have been used to simulate asphalt aging during the service life of the pavement. However, controversy exists regarding the capability of these methods to predict field aging, as various factors interact with the pavement during service and the mechanism behind aging is not fully understood. The two main outcomes of chemical aging are oxidation of asphalt molecules, and change in asphalt SARA (saturate, aromatic, resin, and asphaltene) fractions. Reaction of oxygen with asphalt components forms …

Heating Methods And Detection Limits For Infrared Thermography Inspection Of Fiber-Reinforced Polymer Composites, Jeff R. Brown, H. R. Hamilton

Publications

The use of fiber-reinforced polymer (FRP) composites to strengthen existing civil infrastructure is expanding rapidly. Many FRP systems used to strengthen reinforced concrete are applied using a wet lay-up method in which dry fibers are saturated on site and then applied to the surface. This research investigated using infrared thermography (IRT) as a nondestructive evaluation (NDE) tool for detecting air voids and epoxy-filled holes in FRP systems bonded to a concrete substrate. Four small-scale specimens with FRP thicknesses ranging from 1 to 4 mm (0.04 to 0.16 in.) containing fabricated defects were constructed and inspected in a laboratory setting. Three …