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Articles 1 - 30 of 39
Full-Text Articles in Engineering
Reliability Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon
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.
Initial Assessment Of Liquefied Scrap Tire Concrete, Abdulkareem Kuaryouti, Christopher D. Eamon
Initial Assessment Of Liquefied Scrap Tire Concrete, Abdulkareem Kuaryouti, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
A new approach to incorporate scrap tire material into concrete was investigated, where two reclaimed waste tire components, carbon black and fuel oil, were used to replace a portion of water. The effect of “liquid tire” content to water ratios from 5-40% on an otherwise typical concrete mix were assessed, where compressive and flexural strength, flexural toughness, modulus of elasticity, and several fresh concrete properties were determined. Results were compared to typically expected results of traditional shredded tire mixes with equivalent tire content. It was found that the liquid tire mixes experienced significantly less losses of compressive strength and workability …
Failure Sampling With Optimized Ensemble Approach For The Structural Reliability Analysis Of Complex Problems, Christopher Eamon, Kapil Patki, Ahmad Alsendi
Failure Sampling With Optimized Ensemble Approach For The Structural Reliability Analysis Of Complex Problems, Christopher Eamon, Kapil Patki, Ahmad Alsendi
Civil and Environmental Engineering Faculty Research Publications
Failure sampling is a structural reliability method based on modified conditional expectation suitable for complex problems for which reliability index-based approaches are inapplicable and simulation is needed. Such problems tend to have non-smooth limit state boundaries or are otherwise highly nonlinear. Previous studies recommended implementation of failure sampling with an extrapolation technique using Johnson's distribution or the generalized lambda distribution. However, what implementation method works best is problem dependent. The uncertainty of which approach provides best results for a particular problem limits the potential effectiveness of the method. In this study, a solution is proposed to this issue that eliminates …
Quantitative Resistance Assessment Of Sfrp-Strengthened Rc Bridge Columns Subjected To Blast Loads, Ahmad Alsendi, Christopher D. Eamon
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 …
Load Truncation Approach For Development Of Live Load Factors For Bridge Rating, Sasan Siavashi, Christopher D. Eamon
Load Truncation Approach For Development Of Live Load Factors For Bridge Rating, Sasan Siavashi, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
Various local governments have developed state-specific vehicular live load factors for bridge rating. However, a significant computational demand is often associated with such an effort. This is due to the large size of the weigh-in-motion (WIM) databases frequently used in the procedure. In this study, a method is proposed that can significantly reduce the computational cost of the analysis, while still maintaining reasonable accuracy. The proposed approach develops approximate live load random variable statistics by truncating the WIM database based on gross vehicle weight, then a complete reliability analysis is conducted to develop new live load factors that meet AASHTO-specified …
Development Of Traffic Live Load Models For Bridge Superstructure Rating With Rbdo And Best Selection Approach, Sasan Siavashi, Christopher D. Eamon
Development Of Traffic Live Load Models For Bridge Superstructure Rating With Rbdo And Best Selection Approach, Sasan Siavashi, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
Reliability-based design optimization (RBDO) is frequently used to determine optimal structural geometry and material characteristics that can best meet performance goals while considering uncertainties. In this study, the effectiveness of RBDO to develop a rating load model for a set of bridge structures is explored, as well as the use of an alternate Best Selection procedure that requires substantially less computational effort. The specific problem investigated is the development of a vehicular load model for use in bridge rating, where the objective of the optimization is to minimize the variation in reliability index across different girder types and bridge geometries. …
Reliability-Based Shear Rating Of Prestressed Concrete Bridge Girders Considering Capacity Adjustment Factor, Alaa I. Chehab, Christopher D. Eamon
Reliability-Based Shear Rating Of Prestressed Concrete Bridge Girders Considering Capacity Adjustment Factor, Alaa I. Chehab, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
In this study, the reliability of prestressed concrete (PC) bridge girders in the shear rating process is quantified, where the use of a simple procedure to enhance the accuracy of shear capacity evaluation for rating is evaluated. It was found that the approximate methods used in code-based procedures to develop shear resistance used for reliability calibration of the AASHTO Bridge Design Specifications and the Manual for Bridge Evaluation result in larger discrepancies in reliability than previously assumed, as well as substantially conservative shear capacity evaluation in most cases. To examine the effects of using a more accurate shear rating process, …
Long-Term Durability Of Frp Bond In The Midwest United States For Externally-Strengthened Bridge Components, Sasan Siavashi, Christopher D. Eamon, Abdel A. Makkawy, Hwai-Chung Wu
Long-Term Durability Of Frp Bond In The Midwest United States For Externally-Strengthened Bridge Components, Sasan Siavashi, Christopher D. Eamon, Abdel A. Makkawy, Hwai-Chung Wu
Civil and Environmental Engineering Faculty Research Publications
In this study, the bond strength of a typical FRP system subjected to long-term natural weathering in the Midwest United States is experimentally investigated, and the rate of degradation is estimated. To do this, the bond strength of an FRP system exposed to over fifteen years of weathering is determined with pull-off testing, and a relationship between strength reduction and exposure time is developed using regression analysis. For unweathered specimens, it was found that the attachment strength of the FRP system was governed by the concrete substrate, while for weathered specimens, the FRP system could detach by either a failure …
Huron-To-Erie Water Quality Data Platform, Lanyu Xu, Carol J. Miller, James Olson, Michael Beaulac
Huron-To-Erie Water Quality Data Platform, Lanyu Xu, Carol J. Miller, James Olson, Michael Beaulac
Civil and Environmental Engineering Faculty Research Publications
To address the challenges of environmental degradation, creation of a sustainable urban environment, and increased public engagement and awareness, a mass-oriented, user-friendly and cloud-based data platform has been developed and deployed to provide integrative water quality data in one of the most critical urban corridors of the Laurentian Great Lakes system. In this paper, we describe the data platform developed for the watershed and connecting channels between Lake Huron and Lake Erie, including the St. Clair River, Lake St. Chair, and the Detroit River. This data platform greatly facilitates the access of data across data providers and agencies. Several example …
Pepso: Reducing Electricity Usage And Associated Pollution Emissions Of Water Pumps, Seyed Mohsen Sadatiyan Abkenar, Carol J. Miller
Pepso: Reducing Electricity Usage And Associated Pollution Emissions Of Water Pumps, Seyed Mohsen Sadatiyan Abkenar, Carol J. Miller
Civil and Environmental Engineering Faculty Research Publications
Using metaheuristic optimization methods has enabled researchers to reduce the electricity consumption cost of small water distribution systems (WDSs). However, dealing with complicated WDSs and reducing their environmental footprint remains a challenge. In this study a multi-objective version of Pollution Emission Pump Station Optimization tool (PEPSO) is introduced that can reduce the electricity cost and pollution emissions (associated with the energy consumption) of pumps of WDSs. PEPSO includes a user-friendly graphical interface and a customized version of the non-dominated sorting genetic algorithm. A measure that is called “Undesirability Index” (UI) is defined to assist the search for a promising optimization …
Effect Of Moment Gradient And Load Height With Respect To Centroid On The Reliability Of Wide Flange Steel Beams Subject To Elastic Lateral Torsional Buckling, Christopher D. Eamon, Alexander W. Lamb, Kapil Patki
Effect Of Moment Gradient And Load Height With Respect To Centroid On The Reliability Of Wide Flange Steel Beams Subject To Elastic Lateral Torsional Buckling, Christopher D. Eamon, Alexander W. Lamb, Kapil Patki
Civil and Environmental Engineering Faculty Research Publications
The reliability of doubly-symmetric wide flange steel beams designed to the AISC Specification for Structural Steel Buildings subjected to elastic lateral torsional buckling was evaluated when considering variation in moment gradient and load height. The analysis considers continuous loads on spans subjected to various end moments with supports that are torsionally fixed and laterally supported, without additional intermediate restraints. Dead load, occupancy live load, and beam resistance random variables were considered. Beam lateral torsional buckling resistance was evaluated from numerical solution of a fundamental differential equation that accounts for the effect of moment gradient and load height. In some cases, …
Cement Improved Highly Weathered Phyllite For Highway Subgrades: A Case Study In Shaanxi Province., Xuesong Mao, Carol Jean Miller, Longqi Liu
Cement Improved Highly Weathered Phyllite For Highway Subgrades: A Case Study In Shaanxi Province., Xuesong Mao, Carol Jean Miller, Longqi Liu
Civil and Environmental Engineering Faculty Research Publications
In a cost-saving move, the soft rocks composed of highly-weathered phyllites available onsite were used to fill the subgrade in the eastern Ankang section of the expressway of Shiyan to Tianshui, China. Cement admixture was used to improve the performance of the weathered phyllites. In order to determine the best mix ratio, values corresponding to compaction performance, unconfined compressive strength, and the California bearing ratio (CBR) were analyzed for variable cement content weight percentages (3%, 4%, 5%, and 6%) using test subgrade plots in the field. Field measurements of resilience modulus and deflection confirmed that the strength of the subgrade …
Collapse Resistance Of Moment Resisting Frame And Shear Wall Rc Structural Systems Exposed To Blast, Alaa I. Chehab, Christopher D. Eamon, Joshua Griffin
Collapse Resistance Of Moment Resisting Frame And Shear Wall Rc Structural Systems Exposed To Blast, Alaa I. Chehab, Christopher D. Eamon, Joshua Griffin
Civil and Environmental Engineering Faculty Research Publications
Various characteristics of a structure influence its response when subjected to a blast load. This has important implications for survivability and resistance to progressive collapse. In this study, the effect of the type of lateral load resisting system on reinforced concrete building resistance to progressive collapse when exposed to blast load is examined. Fourteen different reinforced concrete structures were considered for analysis, with five structures designed as moment resisting frames and nine designed as shear walls systems. Buildings with 3, 6, and 10 stories with 3, 4, and 5-bay symmetric configurations were considered. The structures were exposed to external and …
Spatially Explicit Life Cycle Assessment: Opportunities And Challenges Of Wastewater-Based Algal Biofuels In The United States, Javad Roostaei, Yongli Zhang
Spatially Explicit Life Cycle Assessment: Opportunities And Challenges Of Wastewater-Based Algal Biofuels In The United States, Javad Roostaei, Yongli Zhang
Civil and Environmental Engineering Faculty Research Publications
This work presented a Spatially-Explicit-High-Resolution Life Cycle Assessment (SEHR-LCA) model for wastewater-based algal biofuel production, by integrating life cycle assessment, GIS analysis, and site-specific Wastewater Treatment Plants (WWTPs) data analysis. Wastewater resources, land availability, and meteorological variation were analyzed for algae cultivation. Three pathways, Microwave Pyrolysis, hydrothermal liquefaction, and lipid extraction were modeled for bio-oil conversion. This model enables the assessment of seasonal and site-specific variations in productivity and environmental impacts of wastewater-based algal bio-oil across the whole U.S. Model results indicate that wastewater-based algal bio-oil can provide an opportunity to increase national biofuel output. The potential production of algal …
Experimental Investigation Of Discharge Capacity Of Labyrinth Weirs With And Without Nappe Breakers, Omer Bilhan, Emin Emiroglu, Carol J. Miller
Experimental Investigation Of Discharge Capacity Of Labyrinth Weirs With And Without Nappe Breakers, Omer Bilhan, Emin Emiroglu, Carol J. Miller
Civil and Environmental Engineering Faculty Research Publications
Labyrinth weirs provide higher discharge capacity than conventional weirs, with the ability to pass large flows at comparatively low heads. Labyrinth weirs are primarily used as spillways for dams where the spillway width is restricted. In recent years, many research investigations have considered the hydraulic performance of labyrinth weirs, particularly as dependent on the geometric features. The previous work has improved the design basis for such weirs. However, their design still requires experimentally derived and generalized performance curves. It is especially important to observe the behavior of the weir nappe to ensure the design provides hydraulic optimization and to account …
Evaluation Of Alternative Implementation Methods Of Failure Sampling Approach For Structural Reliability Analysis, Kapil Patki, Christopher D. Eamon
Evaluation Of Alternative Implementation Methods Of Failure Sampling Approach For Structural Reliability Analysis, Kapil Patki, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
In this paper, several alternative approaches are used to implement the failure sampling method for structural reliability analysis and are evaluated for effectiveness. Although no theoretical limitation exists as to the types of problems that failure sampling can solve, the method is most competitive for problems that cannot be accurately solved with reliability index-based approaches and for which simulation is needed. These problems tend to have non-smooth limit state boundaries or are otherwise highly nonlinear. Results from numerical integration and three extrapolation approaches using the generalized lambda distribution, Johnson's distribution, and generalized extreme value distribution are compared. A variety of …
Decay Of Pressure Fluctuation In The Hyporheic Zone Around A Cylinder, Timothy Calappi, Carol J. Miller
Decay Of Pressure Fluctuation In The Hyporheic Zone Around A Cylinder, Timothy Calappi, Carol J. Miller
Civil and Environmental Engineering Faculty Research Publications
Erosion around a submerged cylinder is a well-studied problem, and is of particular interest in bridge pier scour applications. Particles erode when lift and drag forces overcome a critical threshold. These forces are typically studied from above the water-riverbed interface and are related to geometry and surficial processes. The present study maps hyporheic pressure fluctuations as they are related to surface water velocity fluctuations. Relatively, high-pressure events in the subsurface promote a destabilizing force from within the riverbed and increase the potential for the mobilization of sediment. Differential pressure transducers were fitted within a vertical cylinder in a movable bed …
Design Live Load Factor Calibration For Michigan Highway Bridges, Christopher D. Eamon, Valid Kamjoo, Kazuhiko Shinki
Design Live Load Factor Calibration For Michigan Highway Bridges, Christopher D. Eamon, Valid Kamjoo, Kazuhiko Shinki
Civil and Environmental Engineering Faculty Research Publications
In this study, a reliability-based calibration of live load factors for bridge design specific to the State of Michigan was conducted. Two years of high frequency WIM data from 20 representative state-wide sites were analyzed, and load effects were generated for bridge spans from 6 to 122 m (20 to 400 ft), considering simple and continuous moments and shears, as well as single lane and two lane effects. Seventy-five year statistics for maximum live load were then estimated with probabilistic projection. Bridge girders considered for the calibration included composite steel, prestressed concrete, side-by-side and spread box beams, as well as …
Field Tests Of Two Prestressed Concrete Girder Bridges For Live Load Distribution And Moment Continuity, Christopher D. Eamon, Alaa Chehab, Gustavo Parra-Montesinos
Field Tests Of Two Prestressed Concrete Girder Bridges For Live Load Distribution And Moment Continuity, Christopher D. Eamon, Alaa Chehab, Gustavo Parra-Montesinos
Civil and Environmental Engineering Faculty Research Publications
Two similar bridges constructed with a live load continuous connection were tested for live load distribution and joint continuity. Girder distribution factors (GDFs) were compared to AASHTO equivalent values. For positive moments on all girders as for negative moments on interior girders, results using AASHTO equivalent GDFs were found to be generally conservative. However, for negative moments on exterior girders, test results exceeded AASHTO values, with 2-lane results significantly so. GDF results were verified with a FEA model, which produced similar behavior to the field tests. With respect to joint continuity, it is estimated that a simple span would produce …
Anthropogenic Impacts To The Sediment Budget Of São Francisco River Navigation Channel Using Swat, Calvin T. Creech, Rafael Brito Siqueira, James P. Selegean, Carol J. Miller
Anthropogenic Impacts To The Sediment Budget Of São Francisco River Navigation Channel Using Swat, Calvin T. Creech, Rafael Brito Siqueira, James P. Selegean, Carol J. Miller
Civil and Environmental Engineering Faculty Research Publications
The São Francisco River Basin, located in eastern Brazil, has undergone a significant amount of anthropogenic changes in the last several decades, such as agricultural expansion, irrigation activities, mining, and the construction of large dams. Together, these changes have altered the historic sediment budget and have led to an aggradation of sediments in the navigation channel, impacting the ability to efficiently ship agricultural commodities to regional ports. In an effort to aid decision makers in future waterway navigation planning, an international partnership between the Brazilian government agency CODEVASF and the US Army Corps of Engineers (USACE) was created. Through this …
Experimental Study Of Soil Water Migration In Freezing Process, Xuesong Mao, Carol J. Miller, Zhongjie Hou, Abdul Khandker
Experimental Study Of Soil Water Migration In Freezing Process, Xuesong Mao, Carol J. Miller, Zhongjie Hou, Abdul Khandker
Civil and Environmental Engineering Faculty Research Publications
Soil water migration is a significant factor in the development of subgrade ice layers in permafrost areas. The prediction of moisture inflow to the freezing zone is an important element in the design and analysis of robust highway subgrade in permafrost regions. In order to better understand moisture inflow to the freezing zone, we designed an experimental investigation to monitor the variation of water content and temperature in freezing soil. Identical experiments were conducted using three different soil types: clay, silt, and fine sand. Moisture was supplied from the sample base while the column was maintained at a constant nonfreezing …
Load Path Uncertainty In A Wood Structure And The Effect On Structural Reliability, Wenqi Wang, Christopher D. Eamon
Load Path Uncertainty In A Wood Structure And The Effect On Structural Reliability, Wenqi Wang, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
The roof truss bearing points of a light-framed wood house were instrumented with load cells. It was found that under dead load alone, symmetric and theoretically identical truss reactions have significant variation. A similar degree of reaction discrepancy was found under the application of uplift pressures caused by hurricane winds. Analysis revealed that the majority of this discrepancy is caused by inherent uncertainties in load path. Although uncertainties in load magnitude and material resistance are accounted for in design by use of appropriate load and resistance factors, load path is generally taken to be deterministic. In this study, load path …
Reliability Analysis Of Reinforced Concrete Columns Exposed To Fire, Christopher D. Eamon, Elin A. Jensen
Reliability Analysis Of Reinforced Concrete Columns Exposed To Fire, Christopher D. Eamon, Elin A. Jensen
Civil and Environmental Engineering Faculty Research Publications
A reliability analysis is conducted on reinforced concrete columns subjected to fire load. From an evaluation of load frequency of occurrence, load random variables are taken to be dead load, sustained live load, and fire temperature. Resistance is developed for axial capacity, with random variables taken as steel yield strength, concrete compressive strength, placement of reinforcement, and section width and height. A rational interaction model based on the Rankine approach is used to estimate column capacity as a function of fire exposure time. Various factors were considered in the analysis such as fire type, load ratio, reinforcement ratio, cover, concrete …
Reliability-Based Design Optimization Of Concrete Flexural Members Reinforced With Ductile Frp Bars, Bashar Behnam, Christopher D. Eamon
Reliability-Based Design Optimization Of Concrete Flexural Members Reinforced With Ductile Frp Bars, Bashar Behnam, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
In recent years, ductile hybrid FRP (DHFRP) bars have been developed for use as tensile reinforcement. However, initial material costs regain high, and it is difficult to simultaneously meet strength, stiffness, ductility, and reliability demands. In this study, a reliability-based design optimization (RBDO) is conducted to determine minimum cost DHFRP bar configurations while enforcing essential constraints. Applications for bridge decks and building beams are considered, with 2, 3, and 4-material bars. It was found that optimal bar configuration has little variation for the different applications, and that overall optimized bar cost decreased as the number of bar materials increased.
Analysis Of Alternative Ductile Fiber-Reinforced Polymer Reinforcing Bar Concepts, Bashar Behnam, Christopher D. Eamon
Analysis Of Alternative Ductile Fiber-Reinforced Polymer Reinforcing Bar Concepts, Bashar Behnam, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
Steel-reinforced concrete structural components are often associated with significant maintenance costs as a result of reinforcement corrosion. To mitigate this problem, fiber-reinforced polymer (FRP) bars have been used in place of traditional steel reinforcement for some applications. The non-ductile response of typical FRP bars is a concern, however. To overcome this problem, hybrid ductile FRP (HDFRP) bars have been developed for use in concrete flexural members with resulting ductility indices similar to sections reinforced with steel. In this study, five different HDFRP bar concepts are analyzed and compared in terms of ductility, stiffness, and relative cost. Of primary interest is …
Resistance Factors For Ductile Frp-Reinforced Concrete Flexural Members, Bashar Behnam, Christopher D. Eamon
Resistance Factors For Ductile Frp-Reinforced Concrete Flexural Members, Bashar Behnam, Christopher D. Eamon
Civil and Environmental Engineering Faculty Research Publications
To prevent damage caused by corroding reinforcement, fiber reinforced polymer (FRP) reinforcing bars have been used in place of steel in a relatively small but increasing number of structures in the civil infrastructure. A concern with the use of traditional FRP bars, however, is the resulting lack of ductility. This problem has been overcome with the development of a new generation of composite reinforcement, ductile hybrid FRP (DHFRP) bars. However, standards that address the design of DHFRP bars are unavailable, and appropriate resistance factors for the use of DHFRP reinforcement are unknown. In this study, a reliability analysis is conducted …
Reliability Analysis Of Rc Beams Exposed To Fire, Christopher D. Eamon, Elin A. Jensen
Reliability Analysis Of Rc Beams Exposed To Fire, Christopher D. Eamon, Elin A. Jensen
Civil and Environmental Engineering Faculty Research Publications
A procedure for conducting reliability analysis of reinforced concrete beams subjected to a fire load is presented. This involves identifying relevant load combinations, specifying critical load and resistance random variables, and establishing a high-temperature performance model for beam capacity. Based on the procedure, an initial reliability analysis is conducted using currently available data. Significant load random variables are taken to be dead load, sustained live load, and fire temperature. Resistance is in terms of moment capacity, with random variables taken as steel yield strength, concrete compressive strength, placement of reinforcement, beam width, and thermal diffusivity. A semi-empirical model is used …
Developing A Family Of Curves For The Hec-18 Scour Equation, Timothy Calappi, Carol J. Miller, Donald Carpenter, Travis Dahl
Developing A Family Of Curves For The Hec-18 Scour Equation, Timothy Calappi, Carol J. Miller, Donald Carpenter, Travis Dahl
Civil and Environmental Engineering Faculty Research Publications
Accurate pier scour predictions are essential to the safe and efficient design of bridge crossings. Current practice uses empirical formulas largely derived from laboratory experiments to predict local scour depth around single-bridge piers. The resulting formulas are hindered by insufficient consideration of scaling effects and hydrodynamic forces. When applied to full-scale designs, these formula deficiencies lead to excessive over prediction of scour depths and increased construction costs. In an effort to improve the predictive capabilities of the HEC-18 scour model, this work uses field-scale data and nonlinear regression to develop a family of equations optimized for various non-cohesive soil conditions. …
Life-Cycle Cost Analysis Of Alternative Reinforcement Materials For Bridge Superstructures Considering Cost And Maintenance Uncertainties, Christopher D. Eamon, Elin A. Jensen, Nabil F. Grace, Xiuwei Shi
Life-Cycle Cost Analysis Of Alternative Reinforcement Materials For Bridge Superstructures Considering Cost And Maintenance Uncertainties, Christopher D. Eamon, Elin A. Jensen, Nabil F. Grace, Xiuwei Shi
Civil and Environmental Engineering Faculty Research Publications
A life cycle cost analysis (LCCA) was conducted on prestressed concrete bridges using carbon fiber reinforced polymer (CFRP) bars and strands. Traditional reinforcement materials of uncoated steel with cathodic protection and epoxy-coated steel were also considered for comparison. A series of deterministic LCCAs were first conducted to identify a range of expected cost outcomes for different bridge spans and traffic volumes. Then, a probabilistic LCCA was conducted on selected structures that included activity timing and cost random variables. It was found that although more expensive initially, the use of CFRP reinforcement has the potential to achieve significant reductions in life …
Reliability Estimation Of Complex Numerical Problems Using Modified Conditional Expectation Method, Christopher D. Eamon, Bulakorn Charumas
Reliability Estimation Of Complex Numerical Problems Using Modified Conditional Expectation Method, Christopher D. Eamon, Bulakorn Charumas
Civil and Environmental Engineering Faculty Research Publications
A simulation-based structural reliability analysis method is presented. It is intended as an alternate approach to estimate reliability for problems for which most-probable point of failure methods fail and when computational resources are limited. The proposed method combines conditional expectation and estimating the PDF or CDF of a selected portion of the limit state. In the proposed approach, complex limit state functions are simplified to two random variable problems. The success of the simplification depends on the quality of the CDF estimate. Results indicate that the method may provide accurate and efficient solutions for some difficult reliability problems.