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Articles 1 - 20 of 20
Full-Text Articles in Engineering
Smooth Static And Dynamic Indentation Of A Cantilever Beam, Minggang Zhou, William P. Schonberg
Smooth Static And Dynamic Indentation Of A Cantilever Beam, Minggang Zhou, William P. Schonberg
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The static and dynamic indentation of structural elements such as beams and plates continue to be intriguing problems, especially for scenarios where large area contacts are expected to occur. Standard methods of indentation analyses use a beam theory solution to obtain an overall load-displacement relationship and then a Hertzian contact solution to calculate local stresses under the indenter. However, these techniques are only applicable in a fairly limited class of problems: the stress distribution in the contact region will differ significantly from a Hertzian one when the contact length exceeds the thickness of the beam. The indentation models developed herein …
Practical Issues For The Application Of High-Performance Concrete To Highway Structures, John J. Myers, Yumin Yang
Practical Issues For The Application Of High-Performance Concrete To Highway Structures, John J. Myers, Yumin Yang
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In recent years, the advantages of high-performance concrete (HPC) have been well documented. Among others, these advantages include enhanced design flexibility and improved durability performance that results in reduced maintenance costs and an increased service life. Despite these obvious benefits, the implementation of HPC has been very slow. This can be attributed to several factors including the uncertainty related to current design codes and a lack of familiarity of designers and contractors with practices and requirements for proper design and construction of high-performance concrete structures. This paper introduces and discusses several fundamental issues that affect the implementation of HPC and …
Pilot Study: Lateral Braced C-Sections Under Bending, B. Beshara, Roger A. Laboube
Pilot Study: Lateral Braced C-Sections Under Bending, B. Beshara, Roger A. Laboube
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The overall behavior under uniform load of cold-formed steel C-sections assemblies was investigated. Each test assembly consisted of C-sections acting as beams having a track section to restrain its ends. A lateral brace to restrain the C-sections from rotation was provided at mid-span. To better understand the influence of the brace on the flexural behavior, an experimental investigation was carried out with particular emphasis placed on the study of the effect of the mid-span brace connection when wallboard was attached to the tension flange. The tested moment capacities are compared to predictions based on the 1996 edition American Iron and …
Biotransformation Of Various Substituted Aromatic Compounds To Chiral Dihydrodihydroxy Derivatives, Henning Raschke, Michael Meier, Roland Hany, Markus D. Muller, Jan Roelof Van Der Meer, Hans-Peter E. Kohler, Joel Gerard Burken
Biotransformation Of Various Substituted Aromatic Compounds To Chiral Dihydrodihydroxy Derivatives, Henning Raschke, Michael Meier, Roland Hany, Markus D. Muller, Jan Roelof Van Der Meer, Hans-Peter E. Kohler, Joel Gerard Burken
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The biotransformation of four different classes of aromatic compounds by the Escherichia coli strain DH5α(pTCB 144), which contained the chlorobenzene dioxygenase (CDO) from Pseudomonas sp. strain P51, was examined. CDO oxidized biphenyl as well as monochlorobiphenyls to the corresponding cis-2,3-dihydro-2,3-dihydroxy derivatives, whereby oxidation occurred on the unsubstituted ring. No higher substituted biphenyls were oxidized. The absolute configurations of several monosubstituted cis-benzene dihydrodiols formed by CDO were determined. All had an S configuration at the carbon atom in meta position to the substituent on the benzene nucleus. with one exception, the enantiomeric excess of several 1,4-disubstituted cis-benzene dihydrodiols formed by CDO …
Benzene Toxicity And Removal In Laboratory Phytoremediation Studies, Joel Gerard Burken, Carla Ross, Lisa M. Harrison, Adrian Marsh, Lars Zetterstrom, Juel S. Gibbons
Benzene Toxicity And Removal In Laboratory Phytoremediation Studies, Joel Gerard Burken, Carla Ross, Lisa M. Harrison, Adrian Marsh, Lars Zetterstrom, Juel S. Gibbons
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Hybrid Poplar Cuttings Were Shown to Impact the Fate and Transport of Subsurface Benzene, While Toxicity to the Poplars Was Not Observed. Laboratory Experiments Investigated the Toxicity Response of Poplar Cuttings to Benzene Exposure, Contaminant Distribution in Plant Tissues, Contaminant Degradation in the Soil Profile, and Contaminant Volatilization from the Soil and Plant Tissues. Two Separate Studies Were Conducted to Evaluate These Parameters. the First Study Examined the Toxicity of Benzene to Hybrid Poplar Cuttings in Batch Reactors. Poplar Cuttings Were Exposed to Various Concentrations of Benzene Contaminated Water in Two Different Types of Soil. Transpiration Rates Were Measured as …
Self-Monitoring, Pseudo-Ductile, Hybrid Frp Reinforcement Rods For Concrete Applications, C. E. Bakis, Antonio Nanni, J. A. Terosky, S. W. Koehler
Self-Monitoring, Pseudo-Ductile, Hybrid Frp Reinforcement Rods For Concrete Applications, C. E. Bakis, Antonio Nanni, J. A. Terosky, S. W. Koehler
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The feasibility of hybrid -fiber-reinforced-polymer rods that demonstrate the important safety features of self-monitoring capability and pseudo-ductility is demonstrated. The rods are intended to be the basis of improved pultruded reinforcements for concrete or other civil applications where safety is of critical importance. The lowest elongation fiber in the seven rods investigated is carbon, which by virtue of its piezo resistivity allows the monitoring of deformation and fracture throughout an entire rod with simple electronic equipment. Resistance measurements obtained during quasi-static tests clearly reveal failure of the carbon fibers. Following this easily detected event, higher loads can be safely sustained …
Characterization Of Frp Rods As Near-Surface Mounted Reinforcement, Laura De Lorenzis, Antonio Nanni
Characterization Of Frp Rods As Near-Surface Mounted Reinforcement, Laura De Lorenzis, Antonio Nanni
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The use of near surface mounted (NSM) fiber-reinforced polymer (FRP) rods is a promising technology for increasing flexural and shear strength of deficient reinforced concrete (RC) members. As this technology emerges, the structural behavior of RC elements strengthened with NSM FRP rods needs to be fully characterized. Given the variability of material properties and groove geometry, this requires that the tensile properties of the FRP rod and the mechanics of load transfer between NSM FRP rods and concrete be investigated. Tensile and bond tests on commercially available carbon FRP deformed rods for application as NSM reinforcement were carried out using …
Diagnostic Load Testing Of Two-Way Posttensioned Concrete Slab, Antonio Nanni, M. Mettemeyer
Diagnostic Load Testing Of Two-Way Posttensioned Concrete Slab, Antonio Nanni, M. Mettemeyer
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Diagnostic load testing techniques have been used to verify in situ that existing structures have the required load-carrying capacity. This paper discusses the diagnostic load testing and finite-element modeling of a two-way posttensioned concrete slab with the purpose of illustrating the features of this full-scale testing method. The slab was modeled using a commercial finite-element package and the results were verified experimentally. The test loads were applied using hydraulic jacks. Negative internal bending moments were generated at critical locations equivalent to those produced by a 92 psf (4.40 kPa) superimposed uniformly distributed load. Positive internal bending moments were also produced …
Asymmetric Low-Velocity Impact Of A Finite Layer, Minggang Zhou, William P. Schonberg
Asymmetric Low-Velocity Impact Of A Finite Layer, Minggang Zhou, William P. Schonberg
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The dynamic indentation of structural elements such as beams and plates continues to be an intriguing problem, especially for scenarios where large area contacts can occur. Standard methods of indentation analysis typically use a dynamic beam theory solution to obtain an overall load-displacement relationship and then a Hertzian contact solution to determine local stresses under the impactor. However, previous static and dynamic modeling efforts have shown that the stress distribution in the contact region will differ significantly from a Hertzian one when the contact length exceeds the thickness of the beam. In such cases point contact can no longer be …
Strain Rate And Aging Effect On The Mechanical Properties Of Sheet Steels, Chi Ling Pan, Shaojie Wu, Wei Wen Yu
Strain Rate And Aging Effect On The Mechanical Properties Of Sheet Steels, Chi Ling Pan, Shaojie Wu, Wei Wen Yu
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This study was primarily involved with the experimental determination of the dynamic mechanical properties of five different sheet steels. The nominal yield strengths of these five types of sheet steels ranged from 172 to 690 MPa (25-100 ksi) and the range of strain rates varied from 10-4 to 1.0 mm/mm/s. All these five materials were studied in both longitudinal and transverse directions under various strain rates, and some materials were also tested under different strain rates and different amounts of prior cold stretching. In addition, two types of steels were tested to estimate the aging effect on the mechanical properties …
Destructive And Non-Destructive Testing Of Bridge J857 Phelps County, Missouri : Strengthening And Testing To Failure Of Bridge Piers, Tarek Alkhrdaji, Antonio Nanni, Genda Chen
Destructive And Non-Destructive Testing Of Bridge J857 Phelps County, Missouri : Strengthening And Testing To Failure Of Bridge Piers, Tarek Alkhrdaji, Antonio Nanni, Genda Chen
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Many of the existing reinforced concrete (RC) bridge piers constructed in the first half of this century were designed as gravity piers with minimal flexural reinforcement and no consideration to seismically induced lateral forces. When considered in earlier designs, the seismic lateral forces were typically low. The potential risk of failure of columns on these piers under a moderate earthquake is becoming a growing concern for the transportation management agencies. In addition, flexural strength deficiency in RC columns may arise from the loss of reinforcement due to corrosion, premature termination of the main reinforcement, or inadequate splicing. One method for …
Editor’S Note Advancement Of Phytoremediation, Joel Gerard Burken
Editor’S Note Advancement Of Phytoremediation, Joel Gerard Burken
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
No abstract provided.
Yield Moment Of Cold-Formed Steel Beams Under Different Strain Rates, Chi Ling Pan, Wei Wen Yu
Yield Moment Of Cold-Formed Steel Beams Under Different Strain Rates, Chi Ling Pan, Wei Wen Yu
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
It has been recognized that the mechanical properties of sheet steels and the structural strength of cold-formed steel members can be influenced by strain rate. For studying the local and post buckling behavior of stiffened and unstiffened compression elements under a dynamic loading condition, 60 beams, which were assembled from the same material, have been tested under different strain rates. To study the structural behavior of hybrid cold-formed steel beams, a total of 72 specimens was investigated. The results showed that the strength of beams increases with increasing strain rates. The amount of increase was found to be dependent on …
Experimental Characterization Of Metallic Dampers For Seismic Retrofit Of Highway Bridges, Genda Chen, Eric R. Bothe, Jeffrey Ger
Experimental Characterization Of Metallic Dampers For Seismic Retrofit Of Highway Bridges, Genda Chen, Eric R. Bothe, Jeffrey Ger
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
The seismic effectiveness of metallic dampers as vibration isolators and energy dissipation devices as well as the dynamic performance of high rocker bearings are investigated experimentally. The scope of the study includes optimizing the metallic dampers for maximum dissipation of energy, characterizing full-scale metallic dampers, and understanding the seismic behavior of a small-scale bridge with dampers. Three full-scale dampers, two of straight and one of linearly tapered rods, were fabricated and tested under a progressive cyclic load. Test results consistently show that the tangential stiffness of the metallic dampers does not degrade significantly as the number of loading cycles increases …
Using Flash Animations And 3d Rendering To Increase The Effectiveness Of Instructional Software, Timothy A. Philpot
Using Flash Animations And 3d Rendering To Increase The Effectiveness Of Instructional Software, Timothy A. Philpot
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Animation and three-dimensional rendering software offers exciting new capabilities that can enhance engineering instructional material. Using these software tools, instructional media can escape the static two-dimensional confines of the printed page or the classroom blackboard. This work-in-progress describes a project to develop instructional material for a Mechanics of Materials course. The paper presents examples of instructional animations, discusses software development tools used to create the animations and discusses early student reaction to the multimedia presentations
Fatigue Assessment Of Traffic Signal Mast Arms Based On Field Test Data Under Natural Wind Gusts, Genda Chen, Jingning Wu, Jiaqing Yu, Lokeswarappa R. Dharani, Michael G. Barker
Fatigue Assessment Of Traffic Signal Mast Arms Based On Field Test Data Under Natural Wind Gusts, Genda Chen, Jingning Wu, Jiaqing Yu, Lokeswarappa R. Dharani, Michael G. Barker
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
In recent years, several states including Missouri, Wyoming, California, and Texas experienced fracture failures of traffic signal mast arms. Almost all the failures are associated with the propagation of defects or cracks. It is therefore imperative to evaluate existing mast arms using a simple yet accurate procedure. A statistical methodology is proposed to predict the fatigue life of signal mast arm structures on the basis of field-measured strain data. The annual occurrence of various stress levels is determined using the historical wind speed data in the vicinity of a mast arm structure and the strain readings of the structure under …
Composites In Construction: Present Situation And Priorities For Future Research, Antonio Nanni, Edoardo Cosenza, Gaetano Manfredi, Andrea Prota
Composites In Construction: Present Situation And Priorities For Future Research, Antonio Nanni, Edoardo Cosenza, Gaetano Manfredi, Andrea Prota
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper was written at the conclusion of the International Workshop titled "Composites for Construction: A Reality," held in Capri, Italy, July 20-21, 2001. Its objective is to collect and summarize main ideas, opinions, evaluations, and proposals that emerged during the discussions held by the participants at break-up and general sessions. For simplicity, the reporting follows the order of such sessions and includes elements from the general sessions when applicable. The paper is intended to help professionals and scientists interested in the study and implementation of composites for the built infrastructure by providing a vivid snapshot of the state-of-the-art situation, …
Permeability Performance Of High-Performance Concrete Subjected To Various Curing Regimes, John J. Myers
Permeability Performance Of High-Performance Concrete Subjected To Various Curing Regimes, John J. Myers
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
Concrete technology has continued to advance throughout the years to meet the demands of designers and innovative structural systems. Traditionally, the most common means to specify durable concrete has been via specifying a maximum water-to-cementitious material ratio or a minimum cement content. With the advent of high-performance concrete (HPC), which often has higher contents of cementitious materials and a variety of admixtures, questions about permeability performance and alternative methods to specify durable concrete have arisen. The study conducted herein comments on the applicability of prescriptive specifications for HPC and investigates the influence of curing regimes and concrete temperature development during …
Experimental Procedure For Testing Of Piles Under Varying Axial And Lateral Loads, Pedro Franco Silva, F. Seible
Experimental Procedure For Testing Of Piles Under Varying Axial And Lateral Loads, Pedro Franco Silva, F. Seible
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
A research program was carried out at the University of California San Diego (UCSD) to study the seismic response of piles and their connections to the pier cap. As part of this research program, an experimental procedure for testing of piles under simulated seismic loading was developed. This experimental procedure was implemented in a research program to test the as-built piles of the San Diego Coronado Bay Bridge piles in order to validate the design criteria recommended by the design team for the seismic retrofit of the Coronado Bay Bridge.
Guides And Specifications For The Use Of Composites In Concrete And Masonry Construction In North America, Antonio Nanni
Guides And Specifications For The Use Of Composites In Concrete And Masonry Construction In North America, Antonio Nanni
Civil, Architectural and Environmental Engineering Faculty Research & Creative Works
This paper covers the latest developments in the preparation of design guidelines, construction specifications, and inspection and quality control recommendations related to the use of composites in construction. The forms of FRP composites addressed are limited to bars and laminates for reinforcement of concrete and masonry structures (new construction and repair/rehabilitation). FRP bars are being used as the internal reinforcement in concrete members when the conventional steel bars may be undesirable for a host of reasons (e.g., corrosion), and principles for design and construction have been established and proposed to industry by the American Concrete Institute (ACI). Conversely, strengthening of …