Engineering Commons^™

Strain And Temperature Measurement From Distributed Fiber Optic Sensors In Performance-Based Fire Engineering, Yanping Zhu

Doctoral Dissertations

"Strain and temperature measurement of steel and concrete structures under fires is critical to the understanding of structural performance yet historically challenging due to a significant gap in measurement science. This Ph.D. study characterizes in six parts low-cost distributed fiber optic sensors and applies them to strain, and temperature measurements based on Rayleigh and Brillouin light scattering. The first part aims to quantify the Rayleigh scattering based measurement accuracy of distributed fiber optic sensors under a heating-holding load protocol and characterize the effect of polymer coating on the sensors as the polymer softens and melts at elevated temperatures. The second …

Nondestructive Condition Assessment Of Civil Infrastructure Using Ultrasonic Technique, Tyler Keith Ashbrook

Graduate Theses, Dissertations, and Problem Reports

Civil Infrastructure controls the way people live by providing safe passage and shelter across the entire globe. Since safety leads the concern in infrastructure, it is essential to ensure that these structures have been adequately tested and analyzed periodically. Testing these structures can be extremely expensive when parts are required to be removed to capture the flaw, which is why nondestructive testing (NDT) continues to grow in demand since it can evaluate the structural component in-situ without causing any damage. Ultrasonic testing (UT) helps to adequately sustain and advance the safety in existing and future infrastructure across the globe. Continual …

Impacts Of Using Tubular Sections In Open Web Steel Joists, Hollis (Cas) L. Caswell V

Honors Theses

Open web steel joists are lightweight structural trusses used in place of I-beams to support long-span floors and roofs of open space buildings. Their slender geometry makes them highly efficient in resisting flexure, but susceptible to out-of-plane buckling in a failure mode known as lateral-torsional buckling. This failure can be avoided by running lateral bracing between joists called bridging or potentially by using tubular sections to build up the joists rather than angle sections.

It is possible that a joist design using tubular cross-sections could require less bridging and prevent the need to use erection bridging for initial joist construction. …

Inelastic Behavior And Seismic Design Of Multistory Chevron-Braced Frames With Yielding Beams, Charles W. Roeder, Andrew D. Sen, Hayato Asada, Sara M. Ibarra, Dawn E. Lehman, Jeffrey W. Berman, Keh-Chyuan Tsai, Ching-Yi Tsai, An-Chien Wu, Kung-Juin Wang, Ruyue Liu

Civil and Environmental Engineering Faculty Research and Publications

Chevron or inverted V-braced frames offer numerous architectural and structural advantages, but the current special concentrically braced frame (SCBF) seismic-design requirements in the American Institute of Steel Construction (AISC) Seismic Provisions for Structural Steel Buildings lead to deep, heavy chevron beams; as a result, few chevron SCBFs are built today. Recent research on single-story chevron SCBFs demonstrated that beam yielding can be advantageous at higher demand levels, and design for large, inelastic unbalanced brace-force demands may still result in acceptable seismic performance. However, this prior research did not consider the response of multistory frames. In particular, questions remain as to …

Steel Bridge Truss Analysis, Alastair Seed

Williams Honors College, Honors Research Projects

The purpose of this project is to conduct a study comparing the effectiveness of different cross frame orientations in lowering the deflection of the main stringers of a bridge. Three different orientations of cross frames were researched; vertical, angled with the superstructure webbing, and halfway-angled. All of these were studied when the stringers were placed directly under the superstructure and when the superstructure was placed outside of the stringers. Analysis was performed in a program called SAP 2000 to find the deflections along the stringers under different loading conditions. The results showed that when the superstructure was oriented over the …

Development Of A Mechanical Device For Measuring Connection Rotations During Seismic Loading, Garrett Tatum

Civil Engineering Undergraduate Honors Theses

This engineering design project sought to design a cheap and easy-to-use sensor to monitor seismic connection rotations in steel buildings during earthquakes by using a linear ratchet mechanism. The idea for the project goes against the mainstream of research that is seeking to develop complex digital networks for monitoring structures in earthquake regions. Whereas many modern sensor networks require high-cost, professionally maintained digital networks, an analog sensor could provide much of the same information at a fraction of the cost, allowing sensors to be more widely utilized, particularly in developing countries. This project required an iterative engineering design process to …

Adhesion Of Bituminous And Cementitious Materials Using Particle-Probe Scanning Force Microscopy, Yujie Li

Graduate College Dissertations and Theses

As the most important materials in civil engineering, bituminous and cementitious materials have been used widely in pavements and constructions for many years. Accurate determination of adhesion is important to the bonding properties of bituminous and cementitious materials. In this work, we presented a novel approach to measure the adhesion between binders and aggregate mineral particles at microscopic scale.

Particle probe scanning force microscopes (SFM) were used to study the adhesion between mineral microspheres representing the primary aggregate constituents (Al2O3, SiO2 and CaCO3) and various control (PG 64-22 and PG 58-22) and modified binders. Results showed that these modified SFM …

Effect Of Continuity Plate Eccentricity On The Performance Of Welded Beam-To-Column Connections, Jason Thomas Norwood

Graduate Theses and Dissertations

Beam-to-column connections in structural steel buildings may have varying degrees of rotational restraint and varying degrees of moment transfer. In fully restrained moment connections, shear is typically transferred through the beam web, while the moment is mostly transferred through the beam flanges which create tension/compression force couples. Column sections that are incapable of resisting these flange forces are often retrofitted with continuity plates within the connection region to improve capacity. In cases of unequal beam depths on either side of the column, an eccentricity between the framed-in beam flange and continuity plate may be required; however, limited research exists to …

Numerical And Experimental Analysis Of Local Buckling Of Axially Loaded Steel Tubes Confined By Concrete And Frp, Nicholas Colbert

Masters Theses

“The hollow core Fiber-Reinforced-Polymer (FRP) concrete circular-steel (HC-FCS) column consists of an outer circular fiber reinforced polymer (FRP) tube, an inner thin-walled circular steel tube concentrically aligned, and a concrete shell between them. Research has been performed on the performance of the member as a whole, but to date, there has been no investigation into the behavior of the steel tube confined in the column. 17 small-scale columns were tested under axisymmetric axial compressions applied directly to the steel tube under displacement control. The conducted parametric study examined the effects of diameter-to-thickness (D/t) ratio, concrete unconfined compressive strength, FRP thickness, …

Evaluation Of Redundancy Of Twin Steel Box-Girder Bridges, Huy V. Pham

FIU Electronic Theses and Dissertations

Based on the definition given in the AASHTO LRFD Bridge Design Specifications, twin steel box-girder bridges are classified as bridges with fracture critical members (FCMs), in which a failure of a tension member is expected to lead to a collapse of the bridge. However, a number of such bridges with either a partial or full-depth crack in one girder have been reported and are still providing service without collapsing. The main objective of this research project is to understand the behavior of twin steel box-girder bridges and to develop methods for evaluating their redundancy level in the event of the …

Dynamic Elasto-Plastic Behavior Of Steel Building Sub-Assemblage Including Cfrp Retrofitting Under Impact Load, Ali Mohammed Salih Aloosi

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents the outcome of a theoretical and experimental study of the dynamic as well as the quasi-static elasto-plastic behavior of a steel building sub-assemblage including carbon fiber reinforced polymer (CFRP) retrofitting. The steel sub-assemblage consists of a beam-column attached to a pair of beams at its top end while its bottom end is fixed. An apparatus is constructed and used for conducting a series of experiments by applying a lateral impact load on the beam-column in the presence or absence of a static axial load. An innovative procedure for determining the shape of the forcing function caused by …

Threshold Chloride Concentration Of Stainless Steels In Simulated Concrete Pore Solution, Hailong Wang, Jiayan Ling, Xiaoyan Sun

International Conference on Durability of Concrete Structures

To evaluate whether stainless steel can replace carbon steel as rebar in reinforced concrete structures exposed to aggressive environment, the threshold chloride concentration of carbon steel, austenitic and duplex stainless steels were experimentally studied in this paper. The solutions with pH ranging from 9.5 to 13.6 were used herein to simulate the pore liquids in both alkaline and carbonated concretes. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were carried out in the solutions with chloride concentration ranging from 0 to 5.0M and at a temperature around 25°C. The activation of pitting corrosion was determined when corrosion current increased and …

Stability Sensitivity Of Low-Rise Steel-Moment Framed Buildings To Hazard-Independent Damage, Trey Reynolds Powell

Electronic Theses and Dissertations

Structural stability has been the subject of much research in recent years. Simply, structural stability may be vieas the ability of the structure’s response to be relatively unaffected by perturbations to its system. Stability of low-rise steel-moment framed buildings and their sensitivity to perturbations from significant damage are the focus of this work. Perturbations, or changes from the normal state of the structural system, have the ability to affect the structural response. Second-order geometric effects imposed through column axial loads, and/or initial out-of-plumbness during the construction process, are a comperturbation in steel framing systems. If the structural members subjected to …

Experimental And Numerical Study On Full-Scale Precast Steel Fibre-Reinforced Concrete Pipes, Nedal Mohamed

Electronic Thesis and Dissertation Repository

Reinforced concrete (RC) pipes are widely used as open channels (non-pressurized pipes) for sewage and storm water conveyance. RC pipes have generally achieved a reliable long-term performance. Depending on multiple parameters (e.g. pipe diameter, pipe wall thickness, required strength, etc.) the pipe may have up to three welded reinforcement cages in order to resist anticipated loads. Each cage is an assembled unit of steel reinforcement consisting of circumferential and longitudinal bars or wires. The fabrication process of a steel cage reinforcement is time and labour consuming. Thus, eliminating the steel cage reinforcement will yield an overall reduction in the production …

Comprehending Performance Of Cross-Frames In Skewed Straight Steel I-Girder Bridges, Jawad H. Gull

FIU Electronic Theses and Dissertations

The effects of support in steel bridges can present significant challenges during the construction. The tendency of girders to twist or layovers during the construction can present a particularly challenging problem regarding detailing cross-frames that provide bracing to steel girders. Methods of detailing cross-frames have been investigated in the past to identify some of the issues related to the behavior of straight and skewed steel bridges. However, the absence of a complete and simplified design approach has led to disputes between stakeholders, costly repairs and delays in the construction.

The main objective of this research is to develop a complete …

Compression Testing And Failure Modes Of Steel-Concrete Composite (Sc) Structures For Nuclear Containment, Patrick Michael Wanamaker, Amit H. Varma

The Summer Undergraduate Research Fellowship (SURF) Symposium

Although being able to provide much cleaner power than burning coal and other fossil fuels, nuclear power plants are still a tough sell to the general public due to their history of being spontaneously dangerous. The containment structures surrounding these nuclear plants, however, can play a huge role in reducing the risks associated with them. Relatively new designs for these containment assemblies, known as SC (steel-concrete composite) structures, aim to increase the strength and durability of the containment facilities while keeping costs down. By varying the spacing between shear studs, the ratio of concrete to steel, and the ratio of …

The Design Of Moment Connections Between Rectangular Hollow Sections, Billy Allen

Theses

Steel portal frames in the construction industry typically comprise 1 and H sections. The design procedures for the connections in these frames (base, eaves and apex) are well established. This research is based on using rectangular hollow sections as the column and rafter members.

The eaves connection of a rectangular hollow section pitched portal frame is investigated in this report and includes a literature review of various experimental research relating to moment connections between rectangular hollow sections.

Three eaves joints were considered in this research. The joints were physically tested in the laboratory and a finite element analysis carried out. …

Structural Behaviour Of Semi-Continuous Steel End Plate Connections, Niall Scollard

Theses

This report focuses on determining the joint stiffness and moment capacity values for semi-continuous (semi-rigid) connections in steel framed structures. When designing a beam to column connection, the assumption that the Joint is either fully continuous or fully pinned may not be entirely valid; it may be more realistic to classify the connection as intermediate between fully pinned and fully continuous.

The development of “the component method”, which is utilised in IS EN 1993-1-8 (EC3) to determine design values of the joint properties is described. A software solution was created using Microsoft Excel to carry out calculations in accordance with …

Kelvin Probe Electrode For Contactless Potential Measurement On Concrete-Properties And Applications, Michael Thomas Walsh

USF Tampa Graduate Theses and Dissertations

The practical feasibility of using a Kelvin Probe as a novel reference electrode in the measurement of both potential and polarization pulse response of reinforcing steel in concrete is demonstrated. Potential values measured using a KP reflect greater stability and repeatability than can typically be attained with conventional reference electrodes. Duplicate reinforced concrete beam test specimens with well-differentiated centrally corroding rebar segments were analyzed using both the Kelvin Probe (KP) and a conventional Saturated Calomel Electrode (SCE). Potential profile maps were developed using potential values recorded under static conditions with both the SCE and the KP. Nominal polarization resistance was …

The Effects Of Bolt Pretension, In-Plane Eccentricity, And Friction On The Ductility Of Block Shear Connections, Kevin M. Zmetra

Master's Theses

Block shear is a complex failure mechanism in bolted and welded steel components such as gusset plates, webs of coped beams, angles and tees. It presumes a combination of tension rupture and shear yield. Multiple variables affect the block shear capacity and ductility of a connection. This study investigates the effects of bolt pretension, connection eccentricity and friction force transfer through a series of destructive experiments followed by refined finite element simulation. Clamping forces create a complex triaxial stress field compounded by the stress concentration at the bolt holes. In-plane load eccentricity with respect to the centerline of the connection …

Steel Angle Section Members Under Combined Axial Load And Unsymmetric Bending, Maheshchandra Rajasekharan Phanibhushan

Civil & Environmental Engineering Theses & Dissertations

This thesis presents the outcome of an investigation into the experimental and theoretical behavior of steel angle section members under combined axial load and unsymmetric bending. Tests are conducted on a series of six angle section members provided with biaxial pinned-end boundaries about the cross-sectional non-principal axes. The end bending moments and axial load are applied in a quasi-static manner until the member load-carrying capacity is reached. The experimental load-deflection and load-strain curves are recorded. The theoretical analysis is based on a system of both elastic as well as materially nonlinear differential equations. The equations were solved using an iterative …

Fatigue Strength Of Steel Bridge Members With Intersecting Welds, David T. Delong, Mark D. Bowman

JTRP Technical Reports

The brittle fracture of the Hoan Bridge in December 2000 highlighted the fracture susceptibility of details containing intersecting welds in steel bridges. Though it is now known that details with intersecting welds should be avoided, many existing bridges in Indiana contain details with intersecting welds. Little experimental data on the fatigue performance of these details exists.

The purpose of this study was to evaluate the fatigue strength of several details commonly found in steel bridges in Indiana that contain intersecting welds. Large-scale experimental fatigue testing were performed using nine steel beams to study the behavior of three basic types of …

Frp Rebar (Afrp, Cfrp, Gfrp), Purdue Ect Team

ECT Fact Sheets

Insufficient concrete cover, poor design or workmanship, and presence of large amounts of aggressive agents including environmental factors all can lead to cracking of the concrete and corrosion of the steel rebar. The problems of steel corrosion are avoided with the use of FRPs because FRP materials are nonmetallic and noncorrosive. In addition, FRP materials exhibit several properties including high tensile strength, that make them suitable for the use as structural reinforcement. Furthermore, codes and design guide provisions have been recently prepared for the use of FRP bars in concrete structures for bridges and buildings.

Post-Tensioned Steel Structure, Purdue Ect Team

ECT Fact Sheets

Welded steel Moment-Resisting Frames (MRFs) were long considered as one the most earthquake-resistant types of structures. Recently, the idea of applying the post-tensioning technology to achieve moment resistant structural systems has been investigated at the University of California, San Diego. Since 1996, moment-resisting connections using post-tensioning concepts have been developed and tested for precast concrete beam-to-column connections, and concrete shear walls.

Long-Term Effects Of Super Heavy-Weight Vehicles On Bridges, Scott M. Wood, Necip Onder Akinci, Judy Liu, Mark D. Bowman

JTRP Technical Reports

A permit truck which exceeds the predefined limit of 108 kips is defined as a superload in Indiana. This study was conducted to examine the long-term effects of superload trucks on the performance of typical slab-on-girder bridges and to assess the likelihood of causing immediate damage. Typical steel and prestressed concrete slab-on-girder type bridges were analyzed using both beam line analysis and detailed finite element models. Furthermore, one prestressed concrete bridge and one steel bridge were instrumented using more than 50 sensors each. Strains and deflections were measured during a live load test, and each bridge was monitored for more …

Synthesis Study: Heat Treatment And Its Effects On Rehabilitating Steel Bridges In Indiana, Matthew Lackowski, Amit Varma

JTRP Technical Reports

The literature review of prior heat straightening research indicated that significant research has been conducted on the development of: (i) heat straightening repair techniques and their field implementation, (ii) guidelines and recommendations for heat straightening repair, (iii) empirical procedures for estimating plastic rotations achieved during heat straightening, (iv) empirical procedures for predicting residual stresses caused by heat straightening, and (v) the effects of heat straightening on the structural properties of repaired bridges. Currently, there is a need for additional research on: (a) the fatigue performance of heat straightened beams, (ii) the effects of single and multiple heat straightening on the …

Fatigue Of Older Bridges In Northern Indiana Due To Overweight And Oversized Loads, Volume 1: Bridge And Weigh-In-Motion Measurements, James A. Reisert, Mark D. Bowman

JTRP Technical Reports

This report is the first of a two-volume final report presenting the findings of the research work that was undertaken to evaluate the fatigue behavior of steel highway bridges on the extra heavy weight truck corridor in Northwest Indiana. The purpose of the study was to evaluate the type and magnitude of the loads that travel along the corridor and then assess the effect of those loads on the fatigue strength of the steel bridge structures on the corridor. This volume presents the results of the experimental field study conducted to evaluate the load and load effects on one steel …

Sensors To Monitor Cfrp/Concrete Bond In Beams Using Electrochemical Impedance Spectroscopy, Sangdo Hong, Ronald S. Harichandran

Civil Engineering Faculty Publications

The use of inexpensive electrochemical impedance spectroscopy based sensor technology for nondestructive evaluation (NDE) of bond degradation between external carbon fiber-reinforced polymer (CFRP) reinforcement and concrete is examined. Copper tape on the surface of the CFRP sheet, stainless steel wire embedded in the concrete, and reinforcing bars were used as the sensing elements. Laboratory experiments were designed to test the capability of the sensors to detect the debonding of the CFRP from the concrete and to study the effect of short-term (humidity and temperature fluctuations) and long-term (freeze-thaw and wet-dry exposure and rebar corrosion) environmental conditions on the measurements. The …

The Examination Of Infra-Red Techniques For Inspection Of Steel Structures I & Ii, Vachirapun Trakulyingyong, Mark D. Bowman

JTRP Technical Reports

Infra-red thermography systems that have been developed over the last few years offer great potential to locate and discover flaws in steel highway bridge structures at a relatively early stage in their development. Under ideal conditions, the use of infra-red instrumentation should allow bridge inspection personnel to rapidly scan the structure and determine if a potential structural problem has developed. If a problem spot is located by the infra-red camera, then the trouble spot can be examined carefully to determine the need for corrective maintenance. The primary purpose of this research study is to evaluate the accuracy and reliability of …

Fatigue Behavior Of Beam Diaphragm Connections With Intermittent Fillet Welds: Part Ii, Brittle Fracture Examination Of The I-64 Blue River Bridge, Mark D. Bowman

JTRP Technical Reports

This report is the second of a two-part, three volume final report presenting the findings of the research work that was undertaken to evaluate the behavior of Indiana highway bridges with diaphragm members welded directly to the web of the primary beams and girders. Fatigue cracks have been observed at several bridges that utilize the welded diaphragm connection. The seriousness of the cracking and the corresponding potential risk on the integrity of the bridge superstructure were assessed. Inspection and repair guidelines for bridges with the welded diaphragm connections were also developed as part of the research effort. This volume presents …