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 …

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. …

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 …

Toward A Seismic Resistant Steel Staggered Truss Framing System (Stf), Ra'ed Al-Mazaidh

Civil Engineering Dissertations

The Staggered Truss Framing (STF) system is a type of steel structural system used in mid- to high-rise buildings. It was initially developed in the 1960s in order to create a steel framing system that has low floor-to-floor height (9 to 10 ft.) and wide column-free space (60 to 80 ft.). This system consists of a series of story-high trusses spanning the total width between two rows of exterior columns and arranged in a staggered pattern on adjacent column lines. Due to the staggered layout, lateral seismic force transfer in the STF system is also in a staggered manner from …

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, …

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 …

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 …

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 …

Performance-Based Seismic Engineering Of Low And Medium-Rise Steel Frames, Saeid Rashidi

Dissertations

The performance level of low and medium-rise steel frames designed according to the common force/strength approach of the UBC or NEHRP is determined. Several combinations of soil profile type, lateral-force-resisting system, and frame-member proportioning are included in the designs.

To evaluate the expected damage, nonlinear models of the designed frames are subjected to a number of actual and simulated ground motion accelerograms and appropriate structural response parameters such as, interstory drift, ductility demand, and dissipated hysteretic energy are obtained. In addition, a modified form of Park-Ang damage index is calculated for moment-resisting frames. The seismic performance of the steel frames …