Engineering Commons^™

Fatigue Performance Of Flexural Retrofits For Precast Slab Bridges, Ian Stewart

All Theses

This thesis discusses flexural and cyclic load testing of two potential retrofits for pre-cast slab bridges. These slabs came from South Carolina Department of Transportation (SCDOT) decommissioned bridges as a part of an ongoing project with SCDOT. The first is a Carbon Fiber Reinforced Plate (CFRP) retrofit where four CFRP plates were adhesively bonded to the bottom of a slab. The second is a steel plate that was mechanically attached to the bottom of a slab using bolted connections. The bolts were cast into grouted holes in the slab. To better understand the failure mode of these retrofits and their …

Flexural Strengthening Of Two-Way Slabs Using Cfrp External Laminates, Shams Abbas Naqvi

Civil Engineering Theses

Deterioration of reinforced concrete structures with time is a common phenomenon, which often leads to reduction in the load carrying capacity. To meet the coding requirements, strengthening of these structures is of utmost importance. Composite materials, such as Carbon Fiber Reinforced Polymers (CFRP), have shown effective results in external strengthening of these structures. However, premature delamination of CFRPs can decrease their efficiency. Recently, pre-saturated CFRP (PS-CFRP), a new type of CFRP pre-impregnated with epoxy resin, was introduced. Previous research has shown that PS-CFRP has shown improved results as compared to regular CFRP (R-CFRP) for strengthening beams and columns. However, no …

Assessment Of Different Seismic Retrofit Systems Of Rc Buildings For Earthquake Risk Mitigation, Aya Ragab Mohamed Abou Ei-Hamd

Theses

Many existing Reinforced Concrete (RC) structures were designed and constructed at a time when design codes were insufficient according to current standards. This class of structures is at risk of damage when subjected to strong earthquake loading. Therefore, several seismic retrofit techniques have been investigated experimentally to increase the earthquake resistance and damage-control potential of pre-seismic code structures using different methods such as quasi-static and pseudo-dynamic testing. However, a limited number of studies have focused on investigating the overall seismic performance of retrofitted RC structures using shake table testing. The first task of this study assesses analytically and experimentally the …

Analysis Of Frp-Wrapped Concrete Piles In Integral Abutment Bridges Subjected To Axial And Cyclic Lateral Loads, Hassan Mohammed Magbool

Theses and Dissertations

ABSTRACT

The long-term maintenance problems associated with expansion joints, which are used to accommodate bridge movements in conventional bridges, have been the primary motivation for the use of integral abutment (jointless) bridges. These bridges rely on the interaction between the structure and the surrounding soil to accommodate bridge movements without the use of any expansion joints on the bridge superstructure. As the bridge superstructure expands and contracts due to seasonal thermal and other strains, relatively large forces can develop in the pile near the pile-cap interface. These reversible moment and shear forces can lead to localized damage near the top …

Detection Of Buried Non-Metallic (Plastic And Frp Composite) Pipes Using Gpr And Irt, Jonas Kavi

Graduate Theses, Dissertations, and Problem Reports

This research investigated alternative strategies for making buried non-metallic pipes (CFRP, GFRP, and PVC) easily locatable using Ground Penetrating Radar (GPR). Pipe diameters up to 12" and buried with up to 4 ft. of soil cover were investigated. The findings of this study will help address the detection problem of non-metallic pipelines and speed the adoption of composite pipes by the petroleum and natural gas industry. The research also investigated the possibility of locating buried pipes transporting hot fluids using Infrared Thermography (IRT).

Results from the study have shown that, using carbon fabric and aluminum tape overlay on non‑metallic pipes …

Viscoelastic Behavior Of Carbon Fiber Reinforced Polymer Composites Incorporating Nanomaterials, Amy R. Garner

Civil Engineering ETDs

Carbon fiber reinforced polymer (CFRP) composites are increasingly being used in a variety of industries such as aerospace and infrastructure. This investigation experimentally examines the effect of incorporating alumina nanoparticles (ANPs), non-functionalized multi-walled carbon nanotubes (NF-MWCNTs), and functionalized multi-walled carbon nanotubes (F-MWCNTs) on the off-axis stiffness and stress-relaxation of carbon fiber reinforced polymer (CFRP) composites. Epoxy- nanocomposites incorporating 0.0, 1.0, 2.0, and 3.0 wt.% ANPs; 0.0 0.5, 1.0, and 1.5 wt. % NF-MWCNTs; 0.0 0.5, 1.0, and 1.5 wt. % F-MWCNTs of the total weight of epoxy are examined. Off-axis tension stiffness and stress-relaxation tests were performed on CFRP coupons …

Development Of Pre-Stressed Retrofit Strategies For Mitigating Fatigue Cracking In Steel Waterway Lock Gate Components, Christine Michelle Lozano

Graduate Theses and Dissertations

Lock gates are an important part of the transportation infrastructure within the United States (US), having many economic, safety, and environmental benefits over rail and highway transportation systems. Unfortunately, many existing lock gates throughout the US have reached or exceeded their initial design life and require frequent repairs to remain in service. Unscheduled repairs often increase as gates age, having a local economic impact on freight transport which can create economic ripples throughout the nation. Fatigue and corrosion are key causes of unscheduled service interruptions, degrading lock gate components over time. Additionally, because lock gates are submerged during operation, crack …

Behavior And Strength Of Rc Spandrel Members Under Unsymmetrical Bending And Torsion Including Cfrp Retrofitting, Muhammad Fahim

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents the outcome of an experimental and theoretical investigation of the behavior and strength of reinforced concrete spandrel members both with and without carbon fiber reinforced polymer (CFRP) retrofitting. Both isolated spandrel members with L-shaped cross section as well as those integrated with reinforced concrete slabs are studied. A series of isolated spandrel members were tested under separate and combined actions of unsymmetrical bending and torsion. Six of these specimens were retrofitted externally with high-strength CFRP strips. Materially nonlinear analysis procedures are also formulated and programmed for the spandrel members with and without CFRP retrofitting. Furthermore, ultimate bending-torsion …

Behavior And Strength Of Non-Prestressed And Prestressed Hillman Composite Beam Including Cfrp Retrofitting, Wajid Khan

Civil & Environmental Engineering Theses & Dissertations

The Hillman Composite Beam (HCB) is a recent innovation used for the first time in 2008 for a bridge construction in USA. It essentially consists of an FRP outer shell, concrete arch inside the shell and steel strands used to tie the two ends of the arch. Being new in the field, the behavior of HCB has not been thoroughly studied. This dissertation presents a study of the flexural behavior and strength of HCB up to the collapse as well as explores the influence of using carbon reinforced polymer (CFRP) retrofitting and prestressed steel for a further increase in HCB …

Strengthening Of Lightweight Reinforced Concrete Beams Using Carbon Fiber Reinforced Polymers (Cfrp), Tariq Al Jaafreh

Civil Engineering Dissertations

This research aimed to investigate the effect of utilizing “Fiber Reinforced Polymer” (FRP) on the light weight concrete beams. The main hypothesis is that such utilization of the FRP will lead to strengthened lightweight beams. The research that has been done on this relationship is somewhat broad in the scope and have mostly focused on the normal-weight concrete. However, only few studies that have considered the light weight concrete. Eight Beams were tested in this research under four point bending test. Two beams were taken as a control beams without any external bonding of Carbon Fiber Reinforced polymer. Another two …

Structural Retrofit Of Reinforced Concrete Circular Columns Using Cfrp, Ahmed Haider Mohiuddin

Civil Engineering Theses

Fiber reinforced polymer (FRP) composites have developed numerous applications in the field of Civil Engineering, mostly because of their beneficial properties like high strength-to=weight ratio and high corrosion resistance. This study presents an easy and expedient finite element (FE) able to accurately estimate the axial load carrying capacity of reinforced concrete (RC) circular columns confined with externally bonded carbon fiber reinforced polymer (CFRP) sheets. The element is able to model collapse due to concrete crushing. The FE generated in this study is used the load carrying capacity of CFRP confined RC columns subjected to concentric loading. Constitutive models for materials …

Strengthening Of Lightweight Reinforced Concrete Beams Using Carbon Fiber Reinforced Polymers (Cfrp), Tariq Al Jaafreh

Civil Engineering Theses

This research aimed to investigate the effect of utilizing “Fiber Reinforced Polymer” (FRP) on the light weight concrete beams. The main hypothesis is that such utilization of the FRP will lead to strengthened lightweight beams. The research that has been done on this relationship is somewhat broad in the scope and have mostly focused on the normal-weight concrete. However, only few studies that have considered the light weight concrete. Eight Beams were tested in this research under four point bending test. Two beams were taken as a control beams without any external bonding of Carbon Fiber Reinforced polymer. Another two …

Normal-Strength And High-Strength Concrete Columns Under Cyclic Axial Load And Biaxial Moment, Mehdi Zarei

Dissertations

The technique of using Carbon Fiber Reinforced Polymer (CFRP) materials to repair and strengthen various concrete members has become popular in the structural retrofitting field as an effective way to enhance the strength and ductility of concrete members due to its superior mechanical properties. In this study a method was introduced to study the behavior of concrete columns with and without CFRP jackets under constant axial load and variable lateral load. The lateral load was applied monotonically and cyclically. To predict the behavior of concrete columns under monotonic and cyclic compressive loadings, a computer code was developed to produce the …

Rapid Repair Of Severely Damaged Rc Columns Under Combined Loading Of Flexure, Shear, And Torsion With Externally Bonded Cfrp, Ruili He

Doctoral Dissertations

"This research aimed to develop a technique to rapidly repair reinforced concrete (RC) bridge columns for emergency service restoration after severe earthquake damage has occurred. Experimental and analytical studies were conducted to study the performance and effectiveness of the proposed repair method. The experimental study included a series of 1/2-scale RC square bridge columns originally tested to failure under constant axial and increasing cyclic lateral loadings resulting in combined flexure, shear, and torsion with different torsional-to-flexural moment ratios. Using externally bonded carbon fiber reinforced polymer (CFRP) sheets, each column was repaired over a 3-day period and then retested under the …

Flexural Mechanical Durability Of Concrete Beams Strengthened By Externally Bonded Carbon Fiber Reinforced Polymer Sheets, Michael Olka

Electronic Theses and Dissertations

About 77,600 bridges throughout the United States in the Federal Highway Association (FHWA) bridge database are listed as structurally deficient. This has created a need to either replace or strengthen bridges quickly and efficiently. Due to high costs for total replacement of deficient bridges, strengthening of existing bridges is a more economical alternative. A technique that has been developing over the past two decades is the strengthening of bridges using carbon fiber reinforced polymer (CFRP) sheets. The CFRP sheets are attached to the bottom of the bridge girders using structural adhesives so that the CFRP becomes an integral part of …

Finite Element Evaluation Of The Effects Of Lateral Anchorage Strips On The Behavior Of Cfrp-Strengthened Rc Beams, Jose Javier Perez

Electronic Theses and Dissertations

In this thesis, a fully nonlinear finite element study of the flexural behavior of doubly reinforced concrete beams strengthened using different Carbon Fiber Reinforced Polymer (CFRP) composite strengthening configurations has been carried out. Prior to the study, a total of six beams were constructed, pre-cracked, strengthened and tested to failure under a four-point loading condition (Zhao and O'Riordan-Adjah, 2004). Then, for the purpose of this thesis work, detailed three dimensional finite element models were created not only to correlate the results obtained from the experiments, but also to predict the load capacity, failure modes and crack pattern of reinforced concrete …