Engineering Commons^™

Parametric Analysis And Enhancement Of The Burst Capacity Model For Composite-Repaired Corroded Pipelines, Rodrigo Silva Silva-Santisteban

Electronic Thesis and Dissertation Repository

One of the main causes of pipeline failures is corrosion, which leads to a localized loss of the pipe wall thickness and hence compromises the capacity of the pipeline. Composite repair is a method to rehabilitate corroded pipelines. Design codes such as ASME PCC-2 are commonly used to design the repair thickness. As the predictive accuracy to determine the burst capacity of a composite repaired pipeline with existing models is generally poor, the main objective of the present thesis is to provide insights on the parameters that affect the burst capacity and propose improvements to the prediction of burst capacity …

Excavation Response Analysis Of Prefabricated Recyclable Support Structure For Water-Rich Silt Foundation Pit, Rui-Song Wang, Cheng-Chao Guo, Pei-Yuan Lin, Fu-Ming Wang

Rock and Soil Mechanics

The prefabricated recyclable support structure provides a new green support system with economic security, functional coordination and sustainable development for the development of underground space. The physical model test of the foundation pit of a pipe-jacking working well in Zhengzhou city is carried out based on the similarity theory. A three-dimensional fluid-solid coupling model that can differentiate the deformation difference between rigid and flexible components in the support system is established by using the ABAQUS software. The stress and deformation characteristics of support structure in the process of dewatering and excavation are analyzed. The influences of dewatering and excavation on …

Performance Of Helical Piles Retrofitted With A Novel Collar Vane Under Lateral And Torsional Loads, Juan Sebastian Carvajal Munoz

Electronic Theses and Dissertations

Helical piles are lightweight deep foundations designed to support both compressive and uplift loads by mobilizing the shear strength of soil adjacent to helical plates that are welded to an extendable shaft. Helical piles are relatively inexpensive, can be installed quickly utilizing non-specialized equipment, and they are suitable for a wide range of soil conditions. However, helical piles are precluded from many applications due to their inability to support substantial lateral and torsional loads. To overcome this limitation, a novel easy-to-install Collar Vane is implemented to augment the lateral and torsional capacity of helical piles.

The Collar Vane consists of …

Empirical Fragility Functions And Numerical Parametric Study For Buckling Of Steel Grain Bins Under High Wind Loads, Andrew Ruder

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

While rural infrastructure is critical to the agricultural industry, it has been historically more susceptible to damage and slower to recover following natural disasters than its urban and suburban counterparts. This has been made evident most recently by the events of the August 10, 2020, derecho in which rural regions in Iowa were among the hardest hit areas with sustained windspeeds exceeding 120 mph. Among the most frequently damaged structures in this event were corrugated steel grain bins, which farmers and co-ops use to dry and store certain commodities. Unlike most other critical structures, steel grain bins are not designed …

Cyclic Behavior Of Laterally Skewed Special Moment Frame Connections: Experimental Testing And System-Level Analyses, Mohammad Hossein Kashefizadeh

Graduate Theses and Dissertations

Special moment frames (SMFs) are frequently used in high seismic areas for architecturally constrained designs. SMFs provide lateral system stiffness without the use of braces that often obstruct views and architectural features. Current American Institute of Steel Construction (ASIC) provisions (AISC 341-16) provide prequalified SMF connection details; however, all prequalified details only consider orthogonal connections between the beam and column. This dissertation investigates the effect of adding skew within SMF beam-to-column connections. The study presented herein involves system-level dynamic time-history analyses of skewed SMF connections, the analytical component-level investigation into the effect of the concrete slab on behavior of the …

Numerical Modeling And Experimental Investigation Of Effective Elastic Properties Of The 3d Printed Gyroid Infill, Philip Bean, Roberto A. Lopez-Anido, Senthil Vel

Civil Engineering Faculty Scholarship

A numerical homogenization approach is presented for the effective elastic moduli of 3D printed cellular infills. A representative volume element of the infill geometry is discretized using either shell or solid elements and analyzed using the finite element method. The elastic moduli of the bulk cellular material are obtained through longitudinal and shear deformations of a representative volume element under periodic boundary conditions. The method is used to analyze the elastic behavior of gyroid infills for varying infill densities. The approach is validated by comparing the Young’s modulus and Poisson’s ratio with those obtained from compression experiments. Results indicate that …

Guidelines For Designing The Overhead Transmission Tower Foundations Adjacent To Cohesionless Slopes, Meshel Q. Alkahtani

Electronic Thesis and Dissertation Repository

Foundations supporting electrical transmission line towers are subjected to oblique loading due to tower own weight along with wind loading. Due to land limitation and linear alignment of transmission lines, many power transmission towers are situated in sand near sloping grounds and proper evaluation of their foundation performance is essential for the safety and reliability of the critical power transmission lines. There is currently no guidance available on the behaviour of transmission towers foundations constructed near slopes. Thus, the primary objectives of this study are to evaluate the response of transmission tower foundations in cohesionless sloping grounds and investigate the …

Evaluation And Damage Detection Of Highway Bridges With Distinct Vulnerabilities, Mohammad Abedin

FIU Electronic Theses and Dissertations

Bridge failures over the past few decades have shown conventional bridge monitoring is insufficient to effectively evaluate the safety of this important piece of infrastructure. Therefore, new methods for bridge monitoring and special considerations in bridge design are needed to ensure the health of these structures as they continue to age and prevent the possibility of catastrophic collapses. The objective of this research is to explore new means for detecting damage in bridge members during normal operations that are both accurate and affordable at the same time. However, to make any damage detection method effective and efficient, the behavior of …

Finite Element Analysis Of Complex Vectorbloc Beam-Column Connections, Labiba Kalam

Electronic Theses and Dissertations

Steel modular construction provides an efficient alternative to traditional construction practices. A key component to modular construction is the connection between the individual modules, which hold the building together against applied loads such as gravity, snow, and wind. The VectorBloc connector is an innovative cast steel connector that is used in the connections between steel modules made from hollow structural steel (HSS) members. The current VectorBloc connector, called VB4, is limited in its uplift capacity and thus faces challenges when applied to structures facing high uplift forces. Thus, a new design of the VectorBloc connector, called VB6, with a focus …

Finite Element Analysis Of Complex Vectorbloc Beam-Column Connections, Labiba Kalem

Electronic Theses and Dissertations

Steel modular construction provides an efficient alternative to traditional construction practices. A key component to modular construction is the connection between the individual modules, which hold the building together against applied loads such as gravity, snow, and wind. The VectorBloc connector is an innovative cast steel connector that is used in the connections between steel modules made from hollow structural steel (HSS) members. The current VectorBloc connector, called VB4, is limited in its uplift capacity and thus faces challenges when applied to structures facing high uplift forces. Thus, a new design of the VectorBloc connector, called VB6, with a focus …

Fragility Functions Of Manufactured Houses Under Earthquake Loads, Shuyah Tani Aurore Ouoba

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

Manufactured homes are factory-built homes made of wooden structural members, then transported and installed on a given site. Manufactured housing is used in many countries, such as in Australia, and in New Zealand but remain mostly popular in the United States. In 2020, nearly 22 million people were estimated to live in manufactured homes in the United States, with an increase of more than fifty percent in the shipment over the past seven years. However, performance observations from the last decades have shown the vulnerability of manufactured homes to extreme events, like windstorms and earthquakes. Damage assessments and post-event evaluations …

Reliability Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The reliability of reinforced concrete bridge columns strengthened with externally bonded, steel-fiber reinforced polymer fabric subjected to blast loads was investigated. Columns were modeled with a nonlinear finite element approach that considers material damage, fracture, and separation. Different concrete strengths, longitudinal reinforcement ratios, and gravity and blast load levels were considered, while uncertainties in material strength and stiffness parameters, as well as load characteristics, were incorporated in the probabilistic analysis. It was found that the use of SFRP can allow significant increases in blast load while maintaining the same level of column reliability.

Finite Element Analysis Of Buckling Capacity Of Conical Steel Tanks Considering Field-Measured Initiation Imperfections – A Case Study, Haoyi Zhang

Electronic Thesis and Dissertation Repository

The geometric imperfection in elevated steel conical water tanks is a key factor that influences the buckling capacity of the tank. Current considerations of imperfections in the design of conical tanks are based on theoretical analysis, whereby the imperfection shapes and locations are assumed to have the most critical impact on the capacity. This thesis investigates the initial imperfections of an actual stiffened liquid-filled steel conical tank (LFCT) based on high-resolution laser scan measurement data of the tank geometry.

In the first part of this study, detailed analyses of the laser scan data were carried out to extract the global …

Finite Element Analyses And Random Field Modeling Of Naturally Corroded Underground Energy Pipelines, Ji Bao

Electronic Thesis and Dissertation Repository

Metal-loss corrosion is one of the major threats to the integrity of oil and natural gas pipelines. The Fitness-For-Service (FFS) assessment is commonly carried out to demonstrate the integrity of the corroded pipelines. The naturally occurring corrosions on the external surfaces are irregularly shaped three-dimensional features. Due to the geometric complexity of the natural corrosion features, the research of FFS assessment in the previous studies always employed the pipe segments containing artificially induced corrosion features. However, since artificial features are in general regular-shaped, e.g. cubic or semi-ellipsoidal, they do not capture geometric characteristics of naturally occurring corrosions. The thesis develops …

Ultimate And Serviceability Limit States Of Large Shallow Foundations Under Combined Loading, Pengpeng He

Electronic Thesis and Dissertation Repository

Estimation of the bearing capacity and deformations of large shallow foundations under combined loadings can be of great significance. Some geotechnical design guidelines recommend the failure load envelope method for ultimate limit state analysis. Since many investigations of this method focus primarily on undrained failure envelopes using unlimited-tension interfaces, zero-tension interfaces have not been well investigated. In addition, less work is available on drained failure envelopes. For serviceability limit states, the majority of approaches used are based on uncoupled, isotropic assumptions. Further work needs to be done on more appropriate elastic solutions for combined loadings.

General VHMT failure envelopes for …

Development Of Multi-Axial Fatigue Retrofits For Lock Gate Components, Logan Verkamp

Graduate Theses and Dissertations

Lock gates are essential infrastructure components to the United State (US) supply chain. They create large cost savings and environmental benefits when compared with traditional methods of transport (freight and rail). Because of the large quantity of goods and dependence on these shipping chains, the US economy can be drastically affected by an unexpected gate closure. Unfortunately, many lock gates within the US have reached or exceeded their designed life. Due to the intensity of cyclic loads and the environment, fatigue cracks have become a prominent issue. Developed cracks near the pintle region (a joint which the gate rotates and …

Quantitative Resistance Assessment Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon

Civil and Environmental Engineering Faculty Research Publications

The blast resistance of a typical reinforced concrete bridge pier column design was modeled with a nonlinear finite element approach that considers material damage, fracture, and separation. While varying concrete strength, amount of longitudinal reinforcing steel, and gravity load, the effect of applying an externally bonded steel fiber reinforced polymer (SFRP) wrapping was assessed. The presented approach uniquely quantifies column blast resistance in terms of charge weight. It was found that blast capacity was roughly linearly related to concrete strength and steel reinforcement ratio, the former of which is most influential. It was further found that a single layer of …

P-Y Curve Of Small-Spaced Row Piles Subjected To Lateral Loads In Marine Clay, Runze Xue, Shean Bie, Linlin Guo

Journal of Marine Science and Technology

Newly proposed pile wall frame structures (PWFSs), notably with small-spaced row piles, have great potential for cofferdams of artificial islands applied for oil recovery in shallow seas. Studies have been called to analyze the bearing performance of small-spaced row piles subjected to lateral loads. A numerical investigation of laterally loaded row piles with small pile spacing was conducted to achieve a fitted algebraic expression of the P-Y curve. Significantly different from the hyperbolic P-Y curves of a single pile reported in other studies, the P-Y curve of small-spaced row piles is similar to an elastic–perfectly plastic curve, which simply depends …

Sway And No-Sway Behaviour Of Pitched Roof Portal Frames Composed Of Cold-Formed Steel Sections, Ghada El-Mahdy Ph.D, P.Eng., Maged Tawfick Hanna Ph.D

Civil Engineering

Cold-formed sections buckle locally and distortionally in combination with overall buckling of the member. When these sections are incorporated into a portal frame structure, this combination of buckling modes affects the overall buckling behaviour of the portal frame. The objective of this paper is to study the effect of local and distortional buckling on the overall behaviour of portal frames. The portal frames studied have a span of 10 m and an eave height of 3 m with a roof pitch of 1:10. Two frames are studied the first with one intermediate interconnector at the midpoints of the column and …

Long-Term Performance Evaluation Of Nudeck In Kearney East Bypass, George Morcous, Marc Maguire

Nebraska Department of Transportation: Research Reports

The Kearney East Bypass bridge is the first project that implements the newly developed precast concrete deck system (known as 2nd generation NUDECK). The new system consists of full-depth full-width precast prestressed concrete deck panels that are 12 ft (3.66 m) long each. The panels have covered shear pockets at 4 ft (1.22 m) spacing on each girder line to host clustered shear connectors that are adjustable in height. Narrow unreinforced transverse joints are used to eliminate the need for deck overlay. Also, deck panels are post-tensioned in the longitudinal direction using a new post-tensioning system that eliminates the need …

Analysis Of Roofs Of Wooden Houses Under Uplift Wind Loads- Analytical Solution, Retrofit, And Reliability Analysis, Adnan Farouk Enajar

Electronic Thesis and Dissertation Repository

Observations of post-hurricane events indicate that light-frame wood houses are vulnerable to failure

Observations of post-hurricane events indicate that light-frame wood houses are vulnerable to failure due to the inability of their connections to provide sufficient transfer of uplift wind loads from the roof of the house to the foundation. One of these connections is the roof-to-wall connection (RTWC), which connects roof trusses to the top plate members of the walls. This issue has been investigated through full-scale testing at the Insurance Research Lab for Better Homes. This thesis describes the detailed finite element modelling performed for this full-scale testing …

Performance Evaluation Of Inverted Tee (It) Bridge System, Garrett P. Martindale, Daniel Watson, Antony Mohsen Kamal Masoud Kodsy, Mostafa Abo El-Khier, Richard L. Wood, George Morcous

Nebraska Department of Transportation: Research Reports

The Inverted Tee (IT) girder bridge system was originally developed in 1996 by the University of Nebraska–Lincoln (UNL) researchers and Nebraska Department of Transportation (NDOT) engineers. This bridge system currently accounts for over 110 bridges in Nebraska used for both state highways and local county roads. Extensive longitudinal and transverse deck cracking have been observed and noted in numerous bridge inspection reports. Since the IT girder bridge system is relatively new, limited data and knowledge exist on its structural performance and behavior. This study evaluates the IT girder bridge system by conducting twenty field observations as well as recording accelerometer, …

Characterization Of Geogrid Reinforced Ballast Behavior Through Finite Element Modeling, Bugra Sinmez

USF Tampa Graduate Theses and Dissertations

Recently, the railway pavement structure system, as an integral part of the transport infrastructure, has been under fast development in some countries such as China, Turkey, and some European Union countries, particularly for the use of high-speed trains. In designing and constructing the railway pavement structure, it is necessary to take into account the infrastructure demand of the High-Speed Railway Lines (HSRL). Compared to traditional railway trains, HSRL can cause more significant problems to the ballast or base layer of commonly used ballasted railway pavements. The deteriorated ballast or base layer may further result in substructure degradation that may cause …

Analytical And Numerical Modeling Of Cavity Expansion In Anisotropic Poroelastoplastic Soil, Kai Liu

LSU Doctoral Dissertations

Cavity expansion/contraction problems have attracted intensive attentions over the past several decades due to its versatile applications, such as the interpretation of pressuremeter/piezocone penetration testing results and the modelling of pile installation/tunnel excavation in civil engineering, and the prediction of critical mud pressure required to maintain the wellbore stability in petroleum engineering. Despite the fact that various types of constitutive models have been covered in the literature on this subject, the soils and/or rocks were usually treated as isotropic geomaterials.

In recognition of the above fact, this research makes a substantial extension of the fundamental cavity expansion theory by considering …

Analysis Of Adhesive Anchorage Systems Under Extreme In-Service Temperature Conditions, Rachel Wang

Masters Theses

Adhesive anchorage systems have found widespread use in structural applications, including bridge widening, concrete repair and rehabilitation, and barrier retrofitting. Because these applications typically require adhesive anchorage systems to be installed outdoors, the effects of climate conditions and day-to-day temperature fluctuations on adhesive behavior and performance should be considered. The purpose of this thesis is to simulate pullout tests of adhesive anchorage systems for threaded rod and reinforcing bars and to emulate effects under various temperature conditions through the use of finite element analysis. Results from the finite element simulation are then compared to the physical tests conducted at UMass …

Performance Of Concrete Tunnel Systems Subject To Fault Displacement, Michael Morano

Masters Theses

A Finite Element Analysis (FEA) investigation of concrete tunnel systems traversing seismic faults is carried out to determine how to effectively mitigate the stresses induced in the liner when subject to fault displacement. A parametric study of various fault parameters, both in the damage zone and competent rock, is carried out to determine the site conditions which induce the most stress on the tunnel liner system. Results indicate that friction angle, cohesion, and elastic modulus of fault zones have varying effects on the stresses induced on the liner. The width of damage zone and expected displacements are also investigated and …

Effect Of Subsurface Conditions On Flexible Pavement Behavior: Non-Destructive Testing And Mechanistic Analysis, Md. Fazle Rabbi

Boise State University Theses and Dissertations

The behavior of flexible pavements under traffic and environmental loading can be significantly affected by subsurface conditions. Inadequate support conditions under the surface can lead to excessive pavement deformations, often leading to structural and functional failure. This research effort focused on assessing the effects of base/subbase and subgrade layer conditions on flexible pavement behavior. The results of this study are presented in the form of two journal manuscripts.

The first manuscript focuses on utilizing pavement structural and functional evaluation data in making pavement rehabilitation decisions. Visual distress surveys and Falling Weight Deflectometer (FWD) testing are often carried out by agencies …

Parametric Study On Multi-Story, Partially Grouted, Perforated, Masonry Shear Walls By Finite Element Analysis, Kyle Henry Chavez

Theses and Dissertations

In this study, parameters related to material properties, geometry, and external stimuli were examined individually to determine their influence on multi-story, partially grouted, perforated (openings), masonry shear walls using a finite element software FormWorks. The parameters studied were: the strength of grouted masonry prisms f'_m,grouted; the strength of un-grouted (hollow) masonry prisms f'_m,ungrouted; the ratio of mortar shear strength to masonry compressive strength; vertical and horizontal reinforcement ratios in terms of size and spacing of reinforcement; axial load; aspect ratio; and openings that were vertically and horizontally altered. To perform this study, finite element models were …

A 3d Numerical Analysis Of The Railway To Compare The Performance Of The Granular And Asphalt Trackbeds., Thammapot Wattanapanalai

Electronic Theses and Dissertations

In the last two decades, trains have been developed either to carry heavy weight of cargo or for high-speed rail transport. Nonetheless, track structure, have not been improved adequate to support the extra loads or dynamic vibrations of high-speed trains. As a result, the performance of track will be affected from heavy freight or high-speed trains. In the long term it results in trackbed damage by increasing the subgrade and ballast displacement. Besides, it negatively affects the performance of the locomotives. Therefore, alternative subballast, should be introduced to reduce the stress and deformation of the track under dynamic or heavy …

Comprehensive Comparison Of Steel Framed Fabric And Conventionally Constructed Aircraft Hangars, Justin M. Iungerich

Theses and Dissertations

Through the life of the United States Air Force (USAF), the accepted method for constructing permanent aircraft hangars is the use of materials such as steel and concrete. However, the emerging type of construction known as steel framed fabric (SFF) construction shows potential to meet the requirements of the USAF at a lower life-cycle cost and with faster construction delivery. A comprehensive comparison to conventional hangars is conducted through the means of an extensive literature review, case study analysis, structural analysis with the use of finite element analysis (FEA) software, and a life-cycle cost comparison. Through examination of Department of …