Structural Engineering Commons^™

Comparison Of Different Power System Resilience Assessment Methods, Jian How Sam Chan

Student Works (2020-2029)

Climate change has been given significant attention in recent times, calling for more ideas to address issues stemming from extreme weather events. Until climate change can be slowed down and ultimately be reversed, it is an imminent objective to find solutions for the mitigation and prevention of the effects of catastrophic weather events. History has a record of the devastation caused by such events on electrical power infrastructures. While electrical power systems have conventionally been designed and built to weather everyday conditions, confronting cataclysmic high-impact, low-probability events will require more resilient attributes. Power systems are often deemed as the backbone …

A Comparative Study On Seismic Analysis Methods And The Response Of Systems With Classical And Nonclassical Damping, Noah G. Bleichner

Master's Theses

This thesis investigated the application of seismic analysis methods and the response of idealized shear frames subjected to seismic loading. To complete this research, a Design Basis Earthquake (DBE) for a project site in San Luis Obispo, CA, and five past earthquake records were considered. The DBE was produced per the American Society of Civil Engineers’ Minimum Design Loads for Buildings and Other Structures (ASCE 7-10) and used for application of the Equivalent Lateral Force Procedure (ELFP) and Response Spectrum Analysis (RSA). When applying RSA, the modal peak responses were combined using the Absolute Sum (ABS), Square-Root-of-the-Sum-of-Squares (SRSS), and Complete …

Design Of Structural Stand For High-Precision Optics Microscopy, Sara T. Novell

Master's Theses

Lawrence Livermore National Lab (LLNL) is home to the National Ignition Facility (NIF), the world’s largest and most energetic laser. Each of the 192 beamlines contains dozens of large optics, which require offline damage inspection using large, raster-scanning microscopes. The primary microscope used to measure and characterize the optical damage sites has a precision level of 1 µm. Mounted in a class 100 clean room with a raised tile floor, the microscope is supported by a steel stand that structurally connects the microscope to the concrete ground. Due to ambient vibrations experienced in the system, the microscope is only able …

Computational Modeling Of Recycled Aggregate Concrete Systems, Anuruddha Jayasuriya

Dissertations

Using recycled concrete aggregates (RCA) as a substitution in concrete materials is an excellent way to improve the sustainability of concrete production. However, due to a lack of globally accepted technical guidance, and high material variability, the usage of recycled aggregate concrete (RAC) systems is not readily practiced within most structural engineering applications.

To date, the majority of the experimental findings in the literature indicate that RAC is a weaker composite material when compared to a natural aggregate concrete system in terms of mechanical properties such as compressive strength, elastic modulus, tensile strength, flexural strength, fracture energy, and toughness. However, …

Reliability Analysis Of Concrete Gravity Dams Under Earthquake Loads, Anu Abraham

LSU Master's Theses

Dams are infrastructure assets of extreme importance; the failure of which can have catastrophic consequences on adjacent communities. Therefore, it is prudent for authorities to evaluate the safety of existing dams in seismically active regions. This thesis focuses on carrying out a reliability analysis of concrete gravity dams under earthquake loads using an enhanced finite element model. For many years, reliability studies on concrete gravity dams were performed using a finite element model that considered a massless foundation and assumed that water is incompressible. Moreover, the design ground motion was applied without any modification either at the bottom fixed boundary …

2-D Non-Linear Finite Element Analysis Of Folsom Dam: Seismically Induced Separation And Pore Pressure Along The Soil-Concrete Interface, Grace Amoussou

Master of Science in Civil Engineering Theses

The seismic soil-concrete interface stability of composite dams has been an area of interest to many researchers. However, the true interface behavior during a seismic event has not been well understood. During a ground shaking, bonding and de-bonding action along the interface may cause significant separation of soil and concrete surfaces, and such a separation may take place at any depth along the interface creating a stability concern for the overall dam. Moreover, the repetitive nature of bonding/debonding behavior may induce excess pore pressure along the interface, which in turn, may trigger a liquefaction failure or a hydraulic fracture in …

Experimental And Numerical Comparison Of Flexural Capacity Of Light Gage Cold Formed Steel Roof Deck, Christopher H. Raeel, Dawid Gwozdz

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

This paper presents an analysis of experimental data and compares it to two numerical analysis methods of light gage cold formed steel roof deck. The flexural capacity was determined upon the first failure mode of the light gage cold formed steel roof deck. A comparison of the experimental data was made to both the effective width method and the direct strength method. The objective of the comparison was to have a physical test provide the actual behavior of the light gage cold formed steel roof deck and grade how well the numerical analysis, effective width and direct strength methods, compare …

Extremely Low Cycle Fatigue Behavior Of Additively Manufactured 17-4ph Stainless Steel, Kaley Collins

Civil Engineering Undergraduate Honors Theses

Steel structures survive seismic loading thanks to components capable of dissipating large amounts of energy through large deformations. Future optimizations of these components include complex free-form geometries that are difficult to fabricate with traditional casting processes. Additive manufacturing (AM) is an alternative for producing optimized free-form geometries. AM material contains significant differences in microstructural characteristics and mechanical behavior compared to its wrought counterparts. Research has been conducted to understand the effect of microscopic features in the high cycle fatigue (HCF) and low cycle fatigue (LCF) regimes. This study focuses on the behavior of 17-4 Precipitation Hardening (PH) stainless steel in …

On The Seismic Performance Of Skewed Special Moment Frame Reduced Beam Section Connections, Damaso Daniel Dominguez

Graduate Theses and Dissertations

Special Moment Frames (SMFs) are frequently used in high seismic areas for architecturally constrained designs, as they provide lateral system stiffness without the use of braces which often obstruct views and architectural features. Reduced beam section (RBS) connections are popular SMF connection details developed following the Northridge earthquake to limit brittle fractures within connection welds. Current American Institute of Steel Construction (ASIC) provisions (i.e. AISC 341-16) provide prequalified SMF RBS connection details (including welding requirements); however, all prequalified details only consider orthogonal connections between the beam and column. This dissertation investigates the effect of adding skew within SMF RBS connections …

Numerical Simulations Of Spread Foundations Supported On Stone Columns Using The Discrete Element Method, Anibal Enrique Santos Marin

Graduate Theses and Dissertations

The implementation of stone columns as a ground improvement technique has become more popular in geotechnical construction practice as a result of their ability to improve strength, stiffness and permeability characteristics of weak clayey soil deposits. There are several analytical and empirical approaches to estimate the bearing capacity of stone column foundation systems; however, there is notable variation in the performance of these existing methods when compared with full-scale experimental results. For very weak cohesive soils (i.e., undrained shear strength less than 15 kPa), the use of conventional stone columns becomes restricted because of the insufficient confinement that these types …

Multiaxial Fatigue Of Notched Steel Plates And Investigation Of Cfrp Retrofits For Crack Initiation Prevention, Ayumi Fujii

Civil Engineering Undergraduate Honors Theses

Fatigue cracks are cracks that result from repeated loading over time, often following millions of loading cycles. Fatigue cracks occur even if the applied load is not large enough to cause material yield. Once a fatigue crack initiates, resulting stress concentrations at the crack tip often make it difficult to arrest the growth of the crack. In order to prevent growth and propagation of fatigue cracks within structural components, it is necessary to alter the stress condition at the crack tip. Fatigue cracks in steel structures resulting from multiaxial loading and or geometry conditions that result in complex states of …

Understanding Workability In Belitic Calcium Sulfoaluminate Concrete Mixtures, Caleb W. Chesnut

Civil Engineering Undergraduate Honors Theses

Belitic Calcium Sulfoaluminate cement (BCSA) is an emerging technology in the concrete industry. BCSA has similar hardened properties to portland cement (PC) but can set in under 20 minutes and reach 4,000 psi in less than 2 hours. Portland cement accounts for 8% of the world’s CO2 emissions, BCSA cements require less energy to produce. Studies have shown that 40% less CO2 is emitted during the production of BCSA cement than portland cement. This environmental benefit also makes it a very promising PC alternative. Before a new material can be used, designers need to understand the material’s properties. The goal …

Preliminary Investigation Of Required Bsca Amount For Soil Cement Mixtures, Mariel Mayori Rivero

Civil Engineering Undergraduate Honors Theses

The recent increase of flooding in the United States and the high expenses related to the damage that these floods have caused to waterway structures suggests a potential interest in rapid setting soil cement to make effective repairs. For this thesis, mix designs of soil only at three different sand-clay proportions were prepared and tested for moisture content and maximum dry density. Due to the early closing of the laboratory and research activities, reliable results were collected from the 70% sand and 30% clay proportions. At those proportions of soil, the optimum moisture content was found to be 8.88% with …

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 …

Final Report - Uav-Enabled Measurement For Spatial Magnetic Field Of Smart Rocks In Bridge Scour Monitoring, Genda Chen, Haibin Zhang, Zhaochao Li

Project SN-1

This project proposed an unmanned aerial vehicle (UAV)-based method to measure the change in magnetic field as a result of the movement of a smart rock to monitor the maximum depth of bridge scour. A high resolution 3-axis magnetometer and global positioning system (GPS) unit were installed on the UAV to obtain the magnetic field intensity and its corresponding coordinate. The optimization algorithm for the localization of smart rock was demonstrated and adopted. The impact factors on accurate smart rock positioning were experimentally investigated. Utilizing finite element method, the influence of steel reinforcing bars on the distribution of ambient magnetic …

Final Report - In-Line Long Period Grating And Brillouin Scattering Fiber Optic Sensors For Strain, Temperature, Chloride Concentration, And Steel Mass Loss Measurement In Bridge Applications, Genda Chen, Chuanrai Guo

Project SN-3

This project developed an in-line grating and scattering fiber optic sensing system for strain, temperature, and steel mass loss measurement in bridge applications. Long period fiber gratings (LPFG) sensors are responsive to thermal and mechanical deformation, and the refractive index change of their surrounding medium. Brillouin scattering sensors are responsive to temperature and strain along an optical fiber. A CO2 laser aided fiber grating system was assembled for LPFG fabrication. To enable mass loss measurement, a low pressure chemical vapor deposition (LPCVD) system was built to synthesize a graphene/silver nanowire composite film as flexible transparent electrode for the electroplating of …

A Prescriptive Criterion For Amphibious Foundation Design, Erin Hughes

Master of Science in Civil Engineering Theses

Flooding is the most frequently occurring natural disaster in the United States and worldwide (FEMA, 2004). Each year, when major flooding ravishes communities, residents are put in danger and often displaced from their homes and jobs for several weeks or months, if not more. The use of amphibious structures as a flood risk mitigation technique has currently only been implemented in individual or small-scale development. Information on the structural design of such buildings is limited and most of the current knowledge regarding amphibious structures is presented in architectural applications. The primary objective of this research is to develop a prescriptive …

The Challenge Of Calculating U-Factors For Cold-Formed Steel C-Shape Wall Assemblies Using Framing Factors, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Development Of A U-Factor Calculation Procedure For Cold-Formed Steel C-Shaped Clear Wall Assemblies, American Iron And Steel Institute

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Using Scrap Tires As An Aggregate In Chip Seal - Phase Ii, Alireza Pourhassan, Ahmed Gheni, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Technical Reports

Chip seals are one of the most cost and performance effective pavement preservation treatments commonly used in the United States. An eco-friendly chip seal pavement, in which the natural aggregate was replaced by crumb rubber obtained from scrap tires, was recently developed by the research team at Missouri S&T, creating rubberized chip seal. This project investigated and optimized the performance of rubberized chip seal under different scenarios. During this project, laboratory chip seal specimens with different sizes were prepared and tested under simulated traffic loads with different loading parameters and environmental conditions. Also, the feasibility of the implementation and performance …