Structural Engineering Commons^™

Efficient Intensity Measures Of Slide-Rocking Structures For Precariously Balanced Rocks, Taylor J. Knickerbocker, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

Precariously balanced rocks (PBRs) and other fragile geologic features are important in both the engineering and seismological communities since they are indicative of the maximum ground motion at a site over the rock’s lifetime. Precariously balanced rocks are individual or stacks of freestanding rocks that tend to respond in rigid body modes when subject to seismic excitation – namely, rocking, sliding, slide-rocking, and free-flight, which can lead to overturning. The seismic response of freestanding structures, such as PBRs, is known to be extremely sensitive to small changes in geometry, position, and earthquake excitation. As such, deterministic methods are limited in …

Analysis Of Standardized Concrete Mixes, Riley Graybeal

Williams Honors College, Honors Research Projects

Concrete is one of the most common materials used in construction. It is mass produced throughout the country, with numerous different designs for concrete mixes. A common practice among concrete manufacturers is to use a standardized concrete mix design. These standardized mix designs are pre-tested and are not usually altered frequently. The hypothesis of this research project is that manufacturers do not constantly investigate new ways to save on their mixes, and simply use the same standardized mix designs.

In this research, investigations into what alterations may reduce the cost of standardized mixes began with a baseline mix design provided …

Damage Assessment Of A Sixteen Story Building Following The 2017 Central Mexico Earthquake, Yijun Liao, Richard L. Wood, M Ebrahim Mohammadi, Kanchan Devkota, Christine E. Wittich

Department of Civil and Environmental Engineering: Faculty Publications

The 2017 M7.1 Central Mexico Earthquake caused significant infrastructural damage in the Mexico City area. The earthquake contained a significant pulse in the long period, resulting in numerous buildings severely damaged or collapsed. This paper discusses a reinforced concrete building which was still partially occupied post-earthquake. The building’s interior walls were examined to have substantial damage, including some extensive cracking. In January 2018, the authors visited the structure and collected detailed assessment data. The data collection included ground-based lidar scans and recorded ambient vibrations of the damaged structure using accelerometers. Eleven scans were collected from the four exterior facades to …

Finite Element Modeling Of Mechanically Stabilized Earth Walls Built With Welded Wire Wall Panels, Dejuan G. Solan

College of Graduate Studies: Theses & Dissertations

In this thesis, a finite element modeling of Mechanically Stabilized Earth (MSE) walls using welded wire wall panels was performed. The implementation of finite element modeling and analysis proved to be quite efficient in simulating the three-dimensional behavior of wall panels that are a part of MSE walls. The comprehensive finite element model included defined concrete and steel material properties in order to present both the realistic behaviors of each component in the model as well as better facilitating and increasing the accuracy of the simulation of numerous finite element analysis (FEA) cases. FEA was employed to simulate welded wire …

Development Of Electromagnetic Friction Dampers For Improving Seismic Performance Of Civil Structures, Mohsen Amjadian

Dissertations and Theses

Energy dissipation is critical to limiting damage to civil structures subjected to extreme natural events such as earthquakes. Friction is one of the most reliable mechanisms of energy dissipation that has been utilized extensively in friction dampers to improve seismic performance of civil structures. Friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably, in spite of the fact that the displacement is generally reduced because of the energy dissipation. This increase in acceleration …

Direct Determination Of The Dynamic Elastic Modulus And Poisson's Ratio Of Timoshenko Prisms And Rods, Guadalupe Leon

Graduate Theses, Dissertations, and Problem Reports (ETD)

In this study, the exact solution of the Timoshenko beam vibration frequency equation under free-free boundary conditions was determined with an accurate shear shape factor. The exact solution was compared with a 3-D finite element calculation using ABAQUS program, and the difference between the exact solution and the 3-D FEM was within 0.15% for both the transverse and torsional modes. Furthermore, relationships between the resonance frequencies and Poisson’s ratio were proposed that can directly determine the elastic constants, unlike the equations provided by ASTM C215. The frequency ratio between the 1^st bending mode and the 1^st torsional mode, …

Bending Response Of Timber Mortise And Tenon Joints Reinforced With Filler-Modules And Frp Gussets, Andrew Robert Pacifico

Graduate Theses, Dissertations, and Problem Reports (ETD)

In 2013, the California Bay Area (CBA) passed a set of ordinances to ensure that their 10,000 plus timber soft-story buildings were prepared for seismic events, through nondestructive evaluation methods. Many property owners are searching for an affordable retrofitting system that will also meet CBA’s new laws focusing on installations by the mandated deadlines in 2020. Over the past three to four decades, Fiber Reinforced Polymer (FRP) composites have found their way into the civil infrastructure sector for rehabilitation. The objective of this study is to evaluate the bending behavior retrofitted mortise and tenon timber joints reinforced with engineered wood …

Structural Behavior Of Steel Plate Embedded Hybrid Gfrp Shapes, Piyush R. Soti

Graduate Theses, Dissertations, and Problem Reports (ETD)

The civil infrastructure industry has been dominated by traditional materials such as steel, timber, and concrete. Although these materials offer great advantages, they have major durability issues in terms of corrosion, decaying, and cracking. Traditional material-based structures deteriorate frequently and require regular-interval repairs with huge expenditures. To resolve these maintenance and durability issues associated with traditional materials, fiber reinforced polymer (FRP) composites have gained some popularity in the past few decades because of their superior mechanical properties and durability. Carbon-FRPs (CFRPs) and glass-FRP (GFRPs) are the most commonly used FRPs in the market. However, in civil engineering applications, CFRPs are …

Short Beam Shear Strength Evaluations Of Gfrp Composites: Correlations Through Accelerated And Natural Aging, William Todd Barker

Graduate Theses, Dissertations, and Problem Reports (ETD)

Fiber Reinforced Polymers (FRP) composites have been materials of interest in replacing or reinforcing steel, wood, and concrete, but lack of understanding of degradation under physical and chemical aging is a main concern. Through many years of research, the understanding of aging or durability of GFRPs has improved. To be able to evaluate aging related degradation rates, an accelerated aging methodology under varying environments is introduced. Accelerated aging is a concept used to age composites in a lab controlled environment under varying pH conditions (2 to 13) and temperatures (~ -20° to +160°F). Once acceleratedly aged testing is completed, Arrhenius …

Retaining Wall System With Soldier Pile And Composite Resin Infused Lagging Elements, Shane Phillip Moore

Graduate Theses, Dissertations, and Problem Reports (ETD)

Retaining walls are used as an alternative to installing drainage and soil reinforcement, depending on site conditions. This report discusses the design of a retaining wall with steel soldier piles and lagging elements for rocky slopes. The design consists of six different options, three options with a span of eight feet and three options with a span of ten feet between soldier piles. The three options for both spans are the same concept but designed for different load conditions. These options include: timber with glass fiber reinforced polymers (GFRP) wraps, reinforced concrete with GFRP wraps, and an FRP Prodeck system …

Field Performance And Rating Evaluation Of A Modular Press-Brake-Formed Steel Tub Girder With A Steel Sandwich Plate Deck, Nicole Marie Hegele Underwood

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Short Span Steel Bridge Alliance (SSSBA) is a group of bridge and culvert industry leaders (including steel manufacturers, fabricators, service centers, coaters, researchers, and representatives of related associations and government organizations) who have joined together to provide educational information on the design and construction of short span steel bridges in installations up to 140 feet in length. The SSSBA technical working group has developed a shallow press-brake-formed tub girder, a trapezoidal cold bent girder, to address the demand in the short span steel bridge market for rapid infrastructure replacement solutions.

Following extensive experimental testing and design work at West …

Design And Performance Of Fiber-Reinforced Concrete With Adapted Rheology For Construction And Repair Of Bridge Structures, Ahmed Abdelrazik

Doctoral Dissertations

“The objective of this document is to design high-performance fiber-reinforced self-consolidating concrete (FR-SCC) for infrastructure repair and fiber-reinforced super-workable concrete (FR-SWC) for bridge construction. The investigated fibers included propylene synthetic fibers, hooked steel fibers, double and triple hooked steel fibers, hybrid crimped steel fiber and polypropylene multifilament fibers, and micro-macro steel fibers. The fiber volume varied between 0 and 0.75%. An expansive agent (EA) was incorporated to compensate for shrinkage and induce compression in the concrete at early age. Two types of EA (G and K) were employed at 0 to 8%, by mass of binder. The investigated FRSCC and …

Long Period Fiber Grating, Thin Coating Of Graphene And Silver Nanowires, And Corrosion Sensing For Life-Cycle Assessment Of Steel Structures, Chuanrui Guo

Doctoral Dissertations

"This study aims to develop and validate a compact, integrated lab-on-sensor system for simultaneous measurement of strain, temperature and corrosion-induced mass loss in steel structures and concrete reinforcement elements in order to assess their life-cycle performance. The sensing system operates based on the principle of long period fiber gratings (LPFG) that are responsive to both thermal and mechanical deformation, and the change in refractive index of any medium surrounding the optical fiber. To fabricate a LPFG sensor for strain and temperature measurement, a CO₂ laser aided fiber grating system was assembled. To enable mass loss measurement, a low pressure …

The Effects Of Silica On The Properties Of Vitreous Enamels, Signo Tadeu Dos Reis, Mike Koenigstein, Liang Fan, Genda Chen, Luka Pavic, Andrea Mogus-Milankovic

Materials Science and Engineering Faculty Research & Creative Works

Ground coat enamels for low carbon steel that contain silica as a mill addition have been developed to study the changes of their properties. Acid-resistant commercial enamel where silica addition was varied from 0 to 10.0 wt % was used for this investigation. The effects of the addition on the corrosion resistance, thermal properties, electrical properties, and mechanical adherence of the enamel to low carbon steel were studied. The corrosion resistance of the steel enameled coupons was tested using a salt spray (fog) apparatus for time periods reaching 168 h at room temperature. It was found that, although the density …

Elevated Temperature Progressive Damage And Failure Of Duplex Stainless Steel, Darren P. Luke

Civil Engineering ETDs

Ductile failure of metals has been the focus of research efforts within academia and industry for many years since it is tremendously important for understanding the failure of structures under extreme loading conditions. However, limited research has been dedicated to elevated temperature ductile failure, which is critical for evaluating catastrophic events such as industrial, structural or shipping vessel fires. A detailed investigation was conducted on the structural response of Duplex Stainless Steel at elevated temperatures. The temperature dependence of elastic modulus, yield strength, ultimate strength, and ductility was measured up to 1000°C and a continuum damage plasticity model was developed. …

Epics Gaqt: Nandi Clean Kitchen Study, Yichen Fan

Engagement & Service-Learning Summit

No abstract provided.

Conversion Of Heat Energy From Cooling Water Of Diesel Engine To Electrical Energy Using Thermoelectric Generator, Muhammad Hasan Albana

Makara Journal of Technology

This research objective is to convert heat from the radiator fluid of a diesel engine to electrical energy by utilizing a thermoelectric generator (TEG). The TEG consists of 20 semiconductors (TE modules) and is equipped with a heat sink. The research shows that using the TEG, the heat of radiator fluid can be converted to electrical energy, although the electricity generated is small. The maximum electrical voltage generated by the TEG when modules were connected in series was 10 volts. When the TE modules were connected in parallel and series-parallel, the maximum voltages generated were 2.11 and 2.53 volts, respectively. …

Immittance Response On Carboxymethyl Cellulose Blend With Polyvinyl Alcohol- Doped Ammonium Bromide-Based Biopolymer Electrolyte, Norfatihah Mazuki, Yuki Nagao, Ahmad Salihin Samsudin

Makara Journal of Technology

The blended carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) doped with various compositions of ammonium bromide (NH4Br)-based solid biopolymer electrolytes (SBEs) were prepared by using the casting method. In this present work, CMC/PVA–NH4Br SBE thin film was used to investigate the electrical conductivity via electrical impedance spectroscopy. The maximum conductivity obtained was 3.21 X 10−4 S cm−1 for sample AB20 at ambient temperature (303 K), and this result might be due to the increased number of charge carrier. A dielectric study was conducted to understand the conductivity behavior. The electrical properties have been measured as a function of frequency of …

Transition Metal Dichalcogenide For High-Performance Electrode Of Supercapacitor, Saifful Kamaluddin Muzakir, Ahmad Salihin Samsudin, Bouchta Sahraoui

Makara Journal of Technology

Molybdenum dichalcogenides have been reviewed from the perspectives of bandgap, conductivity, and oxidation states of transition metal. Researchers have concluded that a narrow-bandgap transition metal dichalcogenide with high conductivity could be achieved for the high-performance electrode of a supercapacitor.

Automated Compilation Test System For Embedded System, Mohamad Khairi Ishak, Ooi Jun Hwan, Teh Jiashen, Nor Ashidi Mat Isa

Makara Journal of Technology

Embedded system testing involves testing an integration of software and hardware. It is increasingly difficult to evaluate the functionality of each module within a short time because of the increasing number of tests required. In this paper, a novel stepwise methodology involving the use of an automated compilation test system (ACTS) is proposed, to improve the quality of testing and optimize the testing time using automation. Using the proposed method, the testing coverage can be maximized, while minimizing the manual work and testing time required. This ACTS was used to automate the test code compilation and execution for different hardware …