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Full-Text Articles in Architecture
Life-Cycle Cost Design Of Deteriorating Structure, Dan M. Frangopol, Kai-Yung Lin, Allen C. Estes
Life-Cycle Cost Design Of Deteriorating Structure, Dan M. Frangopol, Kai-Yung Lin, Allen C. Estes
Architectural Engineering
A lifetime optimization methodology for planning the inspection and repair of structures that deteriorate over time is introduced and illustrated through numerical examples. The optimization is based on minimizing the expected total life-cycle cost while maintaining an allowable lifetime reliability for the structure. This method incorporates: (a) the quality of inspection techniques with different detection capabilities; (b) all repair possibilities based on an event tree; (c) the effects of aging, deterioration, and subsequent repair on structural reliability; and (d) the time value of money. The overall cost to be minimized includes the initial cost and the costs of preventive maintenance, …
Lifetime Bridge Maintenance Strategies Based On System Reliability, Dan M. Frangopol, Allen C. Estes
Lifetime Bridge Maintenance Strategies Based On System Reliability, Dan M. Frangopol, Allen C. Estes
Architectural Engineering
This study proposes a methodology for a system reliability-based condition evaluation of existing highway bridges. The approach is illustrated for an existing steel bridge located in Colorado. USA. An optimum lifetime repair strategy based on minimum expected cost is developed. The initial optimum repair strategy is updated using both biennial visual inspections and specific non-destructive evaluation testing.
Uptake And Metabolism Of Atrazine By Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor
Uptake And Metabolism Of Atrazine By Poplar Trees, Joel Gerard Burken, Jerald L. Schnoor
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Hybrid Poplar Trees Can Uptake, Hydrolyze, and Dealkylate Atrazine to Less Toxic Metabolites. in Whole Plant Studies, the Parent Compound Atrazine and 14C Ring-Labeled Metabolites Were Extracted from Poplar Tissues and Analyzed Via High-Pressure Liquid Chromatography (HPLC) with UV and Radiochromatographic Detectors in Series. the Concurrent Separation and Identification of These Metabolites Has Not Been Previously Reported in Higher Plants for Phytoremediation Applications. Unidentified Metabolites Were Also Detected. Metabolism of Atrazine Occurred in Poplar Roots, Stems, and Leaves and Became More Complete with Increased Residence Time in Tissues. in Poplar Cuttings Exposed to Atrazine for 50 Days, the Parent Compound …
Reliability Of Reinforced Concrete Girders Under Corrosion Attack, Dan M. Frangopol, Kai-Yung Lin, Allen C. Estes
Reliability Of Reinforced Concrete Girders Under Corrosion Attack, Dan M. Frangopol, Kai-Yung Lin, Allen C. Estes
Architectural Engineering
Corrosion of reinforcement is a major problem affecting a large number of reinforced concrete structures. At present, most reliability-based design studies of reinforced concrete structures do not consider the effects of corrosion. In this paper, we present a reliability-based approach to the design of reinforced concrete bridge girders that are under corrosion attack. Both reserve and residual reliability constraints are satisfied. The approach is based on the American Association of State Highway and Transportation Officials (AASHTO) standard specifications for highway bridges and on data of chloride corrosion of steel in concrete. First, the effects of corrosion on both moment and …
Performance-Based Testing Of Chemical Stabilizers, Thomas M. Petry
Performance-Based Testing Of Chemical Stabilizers, Thomas M. Petry
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Chemical stabilizing agents have been introduced that have performed in field applications to improve the behavior of earth materials. The same agents and materials subjected to standardized laboratory tests have often resulted in no improvement. For example, the tests often require pulverization of materials to finer states than are needed in the field or may require remolding when field applications are done in situ, as with injection applications. Some of the physical tests do not place treated materials in a situation resembling conditions in the field, yet they are applied to determine the use of these agents. The experiences of …
Carbon Frp Strengthening Of Doubly Curved Precast Pc Shell, M. Barboni, A. Benedetti, Antonio Nanni
Carbon Frp Strengthening Of Doubly Curved Precast Pc Shell, M. Barboni, A. Benedetti, Antonio Nanni
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In this paper a recent rehabilitation project completed in Italy using carbon fiber reinforced plastic (CFRP) unidirectional sheets is examined. This technology was selected for the strengthening of a doubly curved, precast, prestressed concrete (PC) shell. The shell was part of the roof of an industrial building and had experienced severe localized damage due to accidental heat radiating from a flue. The selection of the CFRP system involved the screening of different repair procedures with relation to the constraints imposed by the owner: limited disturbance to the industrial process, safety of the occupants, low cost, and durability. In addition, the …
University Of Missouri-Rolla Research On Cold-Formed Steel Structures, Wei Wen Yu, Roger A. Laboube
University Of Missouri-Rolla Research On Cold-Formed Steel Structures, Wei Wen Yu, Roger A. Laboube
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
During the past 27 years, numerous research projects have been conducted at the University of Missouri-Rolla (UMR) under the sponsorships of the American Iron and Steel Institute, National Science Foundation, American Society of Civil Engineers, Metal Building Manufacturers Association, Steel Deck Institute, Metal/Lath Steel Framing Association, Chromium Center, Nickel Development Institute, and several steel companies located in the USA, Canada, and South Africa. The purpose of these investigations has been to study the structural strength of cold-formed steel members, connections, and structural systems. Some of the research findings have been used in the development of the AISI Specification for the …
Cold-Formed Steel Webs With Openings: Summary Report, Roger A. Laboube, Wei-Wen Yu, J. E. Langan, M. Y. Shan
Cold-Formed Steel Webs With Openings: Summary Report, Roger A. Laboube, Wei-Wen Yu, J. E. Langan, M. Y. Shan
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Based on a 3-year study that focused on the behavior of cold-formed steel beams with web openings, researchers at the University of Missouri-Rolla have developed simple, easy to apply design recommendations. The design recommendations address the limit states of web buckling resulting from bending, shear, web crippling, combined bending and shear, and combined bending and web crippling. The recommendations were developed based on the results of experimental and analytical studies of C-section beams. The C-sections, which are commonly used for wall studs and floor joists, are manufactured with web openings. Common web opening sizes are 38 x 102mm and 19 …
Multiobjective Optimization Design With Pareto Genetic Algorithm, Franklin Y. Cheng, Dan Li
Multiobjective Optimization Design With Pareto Genetic Algorithm, Franklin Y. Cheng, Dan Li
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper presents a constrained multiobjective (multicriterion, vector) optimization methodology by integrating a Pareto genetic algorithm (GA) and a fuzzy penalty function method. A Pareto GA generates a Pareto optimal subset from which a robust and compromise design can be selected. This Pareto GA consists of five basic operators: reproduction, crossover, mutation, niche, and the Pareto-set filter. The niche and the Paretoset filter are defined, and fitness for a multiobjective optimization problem is constructed. A fuzzy-logic penalty function method is developed with a combination of deterministic, probabilistic, and vague environments that are consistent with GA operation theory based on randomness …