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Articles 511 - 540 of 737

Full-Text Articles in Architectural Engineering

Estimation Of Flight Delay Costs For U.S. Domestic Air Passengers, Hojong Baik, Tao Li, Naveen K. Chintapudi Jan 2010

Estimation Of Flight Delay Costs For U.S. Domestic Air Passengers, Hojong Baik, Tao Li, Naveen K. Chintapudi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Evaluating the economic value of flight delays has always been a keen interest of research groups as well as of federal agencies such as the U.S. Department of Transportation and FAA. However, because of the complexity of the question as well as the incompleteness of available data sets, the estimation of flight delay costs is considered a challenging task in practice. This paper presents a method for estimating domestic air passengers' delay costs incurred by flight delays in U.S. airports. a unique feature of the method is that the costs incurred by flight delays relative to the original flight schedules …

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Some Comments On The Protection Of Lunar Habitats Against Damage From Meteoroid Impacts, William P. Schonberg, F. Schäfer, R. Putzar Jan 2010

Some Comments On The Protection Of Lunar Habitats Against Damage From Meteoroid Impacts, William P. Schonberg, F. Schäfer, R. Putzar

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The establishment of human habitats on the Moon and on Mars will require protecting them from the hazards of near-Earth and interplanetary space. in addition to solar radiation, another hazard to be faced by these habitats is the damage that can result from the high-speed impact of a meteoroid on a critical structural component. Therefore, lunar habitats and their accompanying support facilities need to be designed with adequate levels of protection that will allow them to also withstand the damage that can result from a meteoroid impact. in this paper we discuss some approaches to shielding for lunar habitats, focusing …

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Evaluation Of A Web-Based Learning Tool For Teaching Gis Within The Context Of Transportation Engineering, Ashley Banaszek, Hong Sheng, Richard H. Hall, Ronaldo Luna, Ghulam Bham Jan 2010

Evaluation Of A Web-Based Learning Tool For Teaching Gis Within The Context Of Transportation Engineering, Ashley Banaszek, Hong Sheng, Richard H. Hall, Ronaldo Luna, Ghulam Bham

Business and Information Technology Faculty Research & Creative Works

An Exploratory Study Was Conducted to Evaluate a Web-Based Learning Module for Teaching Geographic Information Systems to Civil Engineering Students within the Context of a Problem Related to Crash Data Analysis. This Module is One Part of a National Science Foundation Course, Curricula, and Laboratory Improvement Project in Which GIS Modules Are Being Developed for Several Areas of Civil Engineering. the Module Was Used as a Laboratory Assignment in a Transportation Engineering Course. Two Days Later Students Completed Both an Objective Multiple-Choice Quiz over the Material Covered in the Lab and a Subjective Questionnaire. Quantitative Analysis Was Carried Out on …

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Diapycnal Diffusivities In Homogeneous Stratified Turbulence, D. D. Stretch, S. K. Venayagamoorthy Jan 2010

Diapycnal Diffusivities In Homogeneous Stratified Turbulence, D. D. Stretch, S. K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Quantifying diapycnal mixing in stably stratified turbulence is fundamental to the understanding and modeling of geophysical flows. Data of diapycnal mixing from direct numerical simulations of homogeneous stratified turbulence and from grid turbulence experiments, are analyzed to investigate the scaling of the diapycnal diffusivity. In these homogeneous flows the instantaneous diapycnal diffusivity is given exactly by Kd= ∈ρ/ (∂ ρ /∂z)2where ∈ρ is the dissipation rate of density fluctuations, and ∂ ρ /∂z is the mean density gradient. The diffusivity Kd may be expressed in terms of the large-scale properties of the turbulence as K d = γLE …

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Control Force Estimation In Seismic Building Design, Xiaozhe Zhang, Franklin Y. Cheng Jan 2010

Control Force Estimation In Seismic Building Design, Xiaozhe Zhang, Franklin Y. Cheng

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents two approaches of estimating the control force magnitude in the building structure's seismic design. One is by spectrum average in frequency domain, and the other is by nondeterministic Monte Carlo analysis in time domain. the spectrum method is proposed to find the estimation by averaging the system's frequency response with an earthquake spectrum as a weighting factor. the nondeterministic method is based on sets of potential ground motions generated numerically. the approaches are developed in the concept of performance design, with studies based on the site potential seismic hazard and presenting results at different levels of displacement …

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Modeling Permanent Deformation Of Unbound Granular Materials Under Repeated Loads, Cheng Chen, Louis Ge, Jiansheng Zhang Jan 2010

Modeling Permanent Deformation Of Unbound Granular Materials Under Repeated Loads, Cheng Chen, Louis Ge, Jiansheng Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Finite-element analysis on a pavement structure under traffic loads has been a viable option for researchers and designers in highway pavement design and analysis. Most of the constitutive drivers used were nonlinear elastic models defined by empirical resilient modulus equations. Few isotropic/kinematic hardening elastoplastic models were used but applying thousands of repeated load cycles became computationally expensive. in this paper, a cyclic plasticity model based on fuzzy plasticity theory is presented to model the long-term behavior of unbound granular materials under repeated loads. the discussion focuses on the model parameters that control long-term behavior such as elastic shakedown. the performance …

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Special Issue On Modeling In Geotechnical Engineering For Design And Materials, R. A. Tarefder, D. H. Chen, Y. N. Ge Jan 2010

Special Issue On Modeling In Geotechnical Engineering For Design And Materials, R. A. Tarefder, D. H. Chen, Y. N. Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

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Finite Element Modeling Of A Field-Scale Shored Mechanically Stabilized Earth Wall, Cheng Chen, Louis Ge, Jia Sheng Zhang Jan 2010

Finite Element Modeling Of A Field-Scale Shored Mechanically Stabilized Earth Wall, Cheng Chen, Louis Ge, Jia Sheng Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The shored mechanically stabilized earth (SMSE) walls are typically used in steep terrain to allow construction of a new road or widening of an existing narrow-road by constructing the wall on the outboard of the roadway. the state-of-practice suggests a minimum bench width and MSE reinforcement length equivalent to seventy percent of the design height of the MSE wall. It has been shown recently that shorter reinforcement length is sufficient when the SMSE wall system is constructed, and the retaining benefits provided by the shoring component should be taken into consideration. in this paper, a finite element analysis is performed …

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Simulation Prototyping Of An Experimental Solar House, Anna Osborne, Stuart Baur, Katie Grantham Jan 2010

Simulation Prototyping Of An Experimental Solar House, Anna Osborne, Stuart Baur, Katie Grantham

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a comparative analysis between an energy simulation model and an actual solar home. the case study used was the Team Missouri's 2009 Solar Decathlon entry. the home was evaluated using the predicted data developed with the use of Energy-10 Version 1.8. the software simulates the energy use performance of building strategies ranging from building envelope and system efficiency options. the performance data used was collected during the 2009 Solar Decathlon competition. Results comparing energy efficient strategies, consumption and generation are explored with future implications discussed. © 2010 by the authors.

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High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 1: Prestress Loss And Camber Behavior, Jared E. Brewe, John J. Myers Jan 2010

High-Strength Selfconsolidating Concrete Girders Subjected To Elevated Compressive Fiber Stresses, Part 1: Prestress Loss And Camber Behavior, Jared E. Brewe, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The design of prestressed concrete members is restricted by the requirement that the extreme compressive fiber stress at midspan of simply supported members be less than 60% of the concrete compressive strength at release of prestressing. the purported purpose of this limit is to address serviceability performance, but it places unnecessary limits on the capability of the materials. for this research program, six prestressed concrete girders were produced with high-strength self-consolidating concrete and subjected to compressive fiber stress levels ranging from 65% to 84% of the concrete compressive strength at release of prestressing. Time dependent concrete surface strains were measured …

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Modeling Resilient Modulus Of Unbound Granular Materials Under Repeated Loading, Cheng Chen, Louis Ge, Jia Sheng Zhang Dec 2009

Modeling Resilient Modulus Of Unbound Granular Materials Under Repeated Loading, Cheng Chen, Louis Ge, Jia Sheng Zhang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Resilient modulus of unbound granular materials is a key design parameter for mechanistic empirical pavement design. But the complexity of the affected factors has made it challenging and difficult for practical designers and researchers to find an appropriate model to describe the entire stress-strain response where the plastic deformation is accumulated during the repeated loading condition. a cyclic plasticity model based on fuzzy sets plasticity theory is presented in this paper to model the resilient modulus and permanent strain behavior of unbound granular materials under repeated loading. the concept of the fuzzy set plasticity is first introduced, followed by its …

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Settlement Of Reinforced Subgrades Under Dynamic Loading, V. K. Puri, S. Kumar, B. M. Das, Shamsher Prakash, B. Yeo Dec 2009

Settlement Of Reinforced Subgrades Under Dynamic Loading, V. K. Puri, S. Kumar, B. M. Das, Shamsher Prakash, B. Yeo

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Model tests were conducted in the laboratory to study the settlement behavior of small size footing resting on geogrid reinforced sand layer and subjected to dynamic loads. Tests were conducted by first subjecting the footing to an initial sustained static load and then superimposing additional predetermined dynamic loads. the frequency of dynamic load was kept at 1 Hz which was well below the resonant frequency of the system. based on the observed test results, the nature of variation of the permanent settlement of the foundation with intensity of static loading and the amplitude of cyclic load are presented in this …

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Ultrasonic Pulse Velocity Tests On Compacted Soil, David M. Weidinger, Louis Ge, Richard Wesley Stephenson Dec 2009

Ultrasonic Pulse Velocity Tests On Compacted Soil, David M. Weidinger, Louis Ge, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In This Paper, Results of a Series of Ultrasonic Pulse Velocity Tests on Compacted Soil Were Presented and Discussed. Ultrasonic Pulse Velocity Tests Provide Compression and Shear Wave Velocity Information that Can Be Used in Calculating Dynamic Elastic Moduli Such as Young's Modulus and Shear Modulus. from the Test Results, Calculated Poisson's Ratio Shows a Linear Relation with the Water Content in Compacted Soil, Which Leads to a Linear Trend in Both P and S Wave Velocity Against Water Content. Furthermore, Presenting Plots in Bulk Density Versus Wave Velocity Gives a Clearer Trend Than Dry Density Versus Wave Velocity. © …

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Structural Damage Localization With Tolerance To Large Time Synchronization Errors In Wsns, Guirong Yan, Shirley J. Dyke, Wei Song, Gregory Hackmann, Chenyang Lu Nov 2009

Structural Damage Localization With Tolerance To Large Time Synchronization Errors In Wsns, Guirong Yan, Shirley J. Dyke, Wei Song, Gregory Hackmann, Chenyang Lu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With Recent Technological Advances in Smart Sensor Platforms, Structural Condition Monitoring Implementations based on Wireless Sensor Networks (WSNs) Have Received Considerable Attention. Modal Identification is an Integral Step in Many Structural Condition Monitoring Systems. However, Accurate Time Synchronization is Not Always Possible, Leading to Incorrect Identification of the Mode Shapes. Although Strict Time Synchronization of the Wireless Sensors Has Been Viewed as Crucial for the Identification of Mode Shapes, a New Perspective is Taken Herein. the Distortion in the Identified Mode Shapes is Characterized and Accommodated. Then the Resulting Mode Shapes Are Used with a Flexibility-Based Damage Detection Approach to …

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Use Of In-Planta Solid Phase Sampling Devices To Delineate Voc Plumes, Joel Gerard Burken, Kendra Waltermire, Emily Sheehan Oct 2009

Use Of In-Planta Solid Phase Sampling Devices To Delineate Voc Plumes, Joel Gerard Burken, Kendra Waltermire, Emily Sheehan

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Plants Directly Interact with Surrounding Water, Air, and Soil, Collecting and Storing Chemicals and Elements from the Surrounding Environment. Two New and Innovative Sampling Methods in Which This Valuable Data Can Be Accessed to Replace as Well as Supplement Contaminated-Site Investigations Have Been Developed. When Determining the Extent of the Plume on a Contaminated Site, Groundwater Sampling May Be Limited Due to Time, Site Access, and Expense. by using New Techniques that Place Sampling Devices Inside the Trees on Site, We Can Sample Trees Naturally Occurring on a Contaminated Site or Those Planted in Phytoremediation or Redevelopment Efforts, Evaluate the …

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Simulations Of Aquaculture Dissolved Waste Transport And Mixing In Near-Coastal Waters, S. K. Venayagamoorthy, O. B. Fringer, J. R. Koseff, R. L. Naylor Oct 2009

Simulations Of Aquaculture Dissolved Waste Transport And Mixing In Near-Coastal Waters, S. K. Venayagamoorthy, O. B. Fringer, J. R. Koseff, R. L. Naylor

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The present study focuses on understanding the transport and fate of dissolved waste from aquaculture pens in near-coastal environments using the hydrodynamic code SUNTANS, which employs unstructured grids to compute flows at very high resolution. We perform simulations of the dissolved waste field and study the effects of different flow conditions (tides and currents) on the evolution of the waste plume. The fish pen causes partial blockage of the flow, leading to the deceleration of the approaching flow and the formation of a downstream wake. Results of the concentration field for an oscillatory flow condition superimposed on a mean current …

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Model For Reinforced Concrete Members Under Torsion, Bending, And Shear. Ii: Model Application And Validation, Gary Greene, Abdeldjelil Belarbi Aug 2009

Model For Reinforced Concrete Members Under Torsion, Bending, And Shear. Ii: Model Application And Validation, Gary Greene, Abdeldjelil Belarbi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A model was recently proposed for predicting the load-deformation response of a reinforced concrete member under torsion combined with bending and shear to spalling or ultimate. This paper shows the application of the model to create interaction surfaces to predict the failure of a member subjected to different ratios of applied torsion, bending, and shear. the model was validated by comparing the predicted and experimental behavior of 28 members from three experimental studies available in the literature. the members were loaded under torsion combined with different ratios of bending, and shear. the torque-twist behavior, reinforcement stress, and concrete surface strain …

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Model For Reinforced Concrete Members Under Torsion, Bending, And Shear. I: Theory, Gary Greene, Abdeldjelil Belarbi Aug 2009

Model For Reinforced Concrete Members Under Torsion, Bending, And Shear. I: Theory, Gary Greene, Abdeldjelil Belarbi

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A model has been developed that can predict the load-deformation response of a reinforced concrete (RC) member subjected to torsion combined with bending and shear to spalling or ultimate capacity. the model can also be used to create interaction surfaces to predict the failure of a member subjected to different ratios of applied torsion, bending, and shear. the model idealizes the sides of a reinforced concrete member as shear "wall panels." the applied loads are distributed to the wall panels as uniform normal stresses and uniform shear stresses. the shear stress due to an applied torsional moment and shear force …

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Lignin And Lipid Impact On Sorption And Diffusion Of Trichloroethylene In Tree Branches For Determining Contaminant Fate During Plant Sampling And Phytoremediation, Gayathri Gopalakrishnan, Joel Gerard Burken, Charles J. Werth Aug 2009

Lignin And Lipid Impact On Sorption And Diffusion Of Trichloroethylene In Tree Branches For Determining Contaminant Fate During Plant Sampling And Phytoremediation, Gayathri Gopalakrishnan, Joel Gerard Burken, Charles J. Werth

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Plants Draw All They Need from their Surrounding Environment and in Doing So Also Draw Anthropogenic Contaminants from their Surroundings. Several Natural Processes (E.g., Active Transport, Diffusion, Sorption, and Degradation) Occur within Trees and Affect Chemical Concentrations in Tree Samples. This Study Elucidates Tree Contaminant Chemical Interactions on Equilibrium Sorption and Diffusion into Branch Tissue (I.e., Wood Core and Bark), Specifically the Impacts of Lipid and Lignin Content. Five Tree Species Were Selected to Span a Range of Lignin and Lipid Contents. Linear Isotherms Were Obtained for All Sampled Species over a Limited Concentration Range (2 Μg/ ML < C Gas < 12 Μg/mL), and Equilibrium Distribution Coefficients (Kd) Were Linearly Correlated to Lipid (R2 > 0.83) But …

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Conference Review - 4th International Phytotechnologies Conference, Denver, Co, September 24-26, 2007, Jason C. White, Joel G. (Gerard) Burken Jul 2009

Conference Review - 4th International Phytotechnologies Conference, Denver, Co, September 24-26, 2007, Jason C. White, Joel G. (Gerard) Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

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Why Is Fresh Self-Compacting Concrete Shear Thickening?, Dimitri Feys, Ronny Verhoeven, Geert De Schutter Jun 2009

Why Is Fresh Self-Compacting Concrete Shear Thickening?, Dimitri Feys, Ronny Verhoeven, Geert De Schutter

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Rheological Properties of Fresh Concrete Are Mostly Described by Means of the Bingham Model. for Self-Compacting Concrete, the Bingham Model is Applicable in a Lot of Cases, But Some Authors Report that the Rheological Behavior is Non-Linear. the Apparent Viscosity Increases with Increasing Shear Rate and the SCC Shows Shear Thickening Behavior. Shear Thickening Becomes Important in Operations Occurring at High Shear Rates, Like Mixing and Pumping. in These Cases, Shear Thickening Should Not Be Forgotten in Order to Avoid Breaking of the Mixer, Pump or Pipes. This Paper Will Describe Two Possible Theories for Shear Thickening Behavior of …

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Integration Approach Of The Couette Inverse Problem Of Powder Type Self-Compacting Concrete In A Wide-Gap Concentric Cylinder Rheometer. Part Ii. Influence Of Mineral Additions And Chemical Admixtures On The Shear Thickening Flow Behaviour, G. Heirman, R. Hendrickx, L. Vandewalle, D. Van Gemert, D. (Dimitri) Feys, G. De Schutter, B. Desmet, J. Vantomme Mar 2009

Integration Approach Of The Couette Inverse Problem Of Powder Type Self-Compacting Concrete In A Wide-Gap Concentric Cylinder Rheometer. Part Ii. Influence Of Mineral Additions And Chemical Admixtures On The Shear Thickening Flow Behaviour, G. Heirman, R. Hendrickx, L. Vandewalle, D. Van Gemert, D. (Dimitri) Feys, G. De Schutter, B. Desmet, J. Vantomme

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The Influence of Mineral Additions and Chemical Admixtures on the Shear Thickening Flow Behavior of Powder Type Self-Compacting Concrete (SCC) is Studied by Means of a Wide-Gap Concentric Cylinder Rheometer. the Couette Inverse Problem is Treated by Means of the Integration Method in Order to Derive the Flow Curve Τ(Γ̇) from the Torque Measurements. According to the Experimental Results, the Shear Thickening Effect is Found to Be Strongly Influenced by the Addition of the Chemical Admixture (A Polycarboxylate Ether based Superplasticizer), Whereas Mineral Additions Were Found to Modify the Intensity of Shear Thickening. the Limestone, Quartzite and Fly Ash Addition …

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Taproot™ Technology: Tree Coring For Fast, Noninvasive Plume Delineations, Joel Gerard Burken, Sallie Bailey, Matt Shurtliff, Jeff Mcdermott Jan 2009

Taproot™ Technology: Tree Coring For Fast, Noninvasive Plume Delineations, Joel Gerard Burken, Sallie Bailey, Matt Shurtliff, Jeff Mcdermott

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In Efforts to Evaluate the Use of Plants as a Forensic Tool for Delineating Contaminated Soil and Groundwater, a Laboratory Experiment and a Field Sampling Effort Were Undertaken. Site Assessments Are Often Costly and Inaccurate, Requiring Multiple Mobilizations to Hone in on Source Areas and Getting Accurate Estimates of Contaminant Extent and Distribution. as These Extensive Site Delineations Take Place, Valuable Time and Resources Are Lost. the Findings of This Study Show that Plants Can Be Used as a Tool to Evaluate a Variety of Subsurface Contaminants, Either in the Vadose Zone or in the Saturated Zone. in the First …

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Risk Indexes For Draft Ccl3 Chemicals, J. Alan Roberson, Matthew Lueders, Craig Adams, Jeffrey S. Rosen Jan 2009

Risk Indexes For Draft Ccl3 Chemicals, J. Alan Roberson, Matthew Lueders, Craig Adams, Jeffrey S. Rosen

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

To supplement the processes used for developing the draft third Contaminant Candidate List (CCL3) and better inform decisions made by the US Environmental Protection Agency on future CCLs, the authors offer an evaluation tool for efficiently synthesizing, visualizing, and organizing data for effective comparisons among contaminants. Graphical presentations of health effects-occurrence indexes were developed for more than 300 chemical contaminants, including those on the draft CCL3. a risk indexes framework was then used to elucidate the extent of available data, the data quality, and the underlying uncertainties for occurrence and toxicity. Choosing the appropriate contaminant for regulation is a complex …

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Predicting The Perforation Response Of Honeycomb Sandwich Panels Using Ballistic Limit Equations, William P. Schonberg, Frank Schäfer, Robin Putzar Jan 2009

Predicting The Perforation Response Of Honeycomb Sandwich Panels Using Ballistic Limit Equations, William P. Schonberg, Frank Schäfer, Robin Putzar

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Man-made debris from previous spacecraft missions poses a serious threat to spacecraft that are launched to operate in Earth orbit because it can strike such spacecraft at extremely high velocities and consequently damage mission-critical systems. Most satellites are constructed with honeycomb sandwich panels as their primary structural elements. to be able to perform a risk analysis, it is important to know, in the event of such a meteoroid or orbital debris particle impact, whether or not the impacting particle or parts thereof will exit the rear of the sandwich panel. a recently developed set of ballistic limit equations for two …

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Liquefaction Behavior Of Mississippi River Silts, Ali M. Izadi, Ronaldo Luna, Richard Wesley Stephenson Dec 2008

Liquefaction Behavior Of Mississippi River Silts, Ali M. Izadi, Ronaldo Luna, Richard Wesley Stephenson

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Civil Infrastructure Built on Alluviums and Recent Deposits, Such as Dams, Contain Significant Amount of Silts. the Static and Dynamic Behavior of These Fine-Grained Soils Has Been Investigated Less Than the Clay-Like or Sand-Like Soils. Low Plasticity Silts (PI = 6) Obtained East of St. Louis in Illinois Are Known as Loess that Has Been Re-Deposited by Water in the Floodplains of the Mississippi River. These Silts Were Reconstituted in the Laboratory by Slurry at Water Content above the Liquid Limit and Then Consolidated to an Initial Effective Stress. the Initial Laboratory Characterization under Monotonic Loading Included a Series of …

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Piles Under Earthquake Loads, Shamsher Prakash, Vijay K. Puri Dec 2008

Piles Under Earthquake Loads, Shamsher Prakash, Vijay K. Puri

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Piles are preferred type of foundation for supporting structures in seismic areas. their performance is affected by soil, pile and earthquake related parameters. in non-liquefying soils, the shear modulus may degrade, and material damping may increase with increasing strain/displacement. in liquefying soils, the lateral ground displacement may lead to increased lateral loads and moments on the pile leading to pile failure in bending. the loss of lateral support can also lead to buckling type failure. These issues for pile design in seismic areas are examined. © 2008 ASCE.

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Fresh Self Compacting Concrete, A Shear Thickening Material, Dimitri Feys, Ronny Verhoeven, Geert De Schutter Jul 2008

Fresh Self Compacting Concrete, A Shear Thickening Material, Dimitri Feys, Ronny Verhoeven, Geert De Schutter

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In Literature, the Rheological Properties of Concrete Have Been Investigated Thoroughly, resulting in a Simple Description, in Steady State, by Means of the Bingham Model. Self-Compacting Concrete Shows a Lower Yield Stress, Which in Some Cases is Very Close to Zero, or Can Even Appear to Be Negative When Extrapolating the Bingham Model. in the Latter Case, the Bingham Model is Not Valid and Other Solutions Must Be Found. in This Paper, the Non-Linearity - or Shear Thickening - in the Rheological Behavior of Fresh SCC is Described with the Modified Bingham Model, after the Elimination of Possible Measurement Artefacts. …

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Effects Of Ionic Strength, Temperature, And Ph On Degradation Of Selected Antibiotics, Keith A. Loftin, Craig D. Adams, Michael T. Meyer, Rao Surampalli Mar 2008

Effects Of Ionic Strength, Temperature, And Ph On Degradation Of Selected Antibiotics, Keith A. Loftin, Craig D. Adams, Michael T. Meyer, Rao Surampalli

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Aqueous degradation rates, which include hydrolysis and epimerization, for chlorretracycline (CTC), oxytetracycline (OTC), tetracycline (TET), lincomycin (LNC), sulfachlorpyridazine (SCP), sulfadimethoxine (SDM), sulfathiazole (STZ), trimethoprim (TRM), and tylosin a (TYL) were studied as a function of ionic strength (0.0015, 0.050, or 0.084 mg/L as Na2HPO4), temperature (7, 22, and 35°C), and pH (2, 5, 7, 9, and 11). Multiple linear regression revealed that ionic strength did not significantly affect (α = 0.05) degradation rates for all compounds, but temperature and pH affected rates for CTC, OTC, and TET significand (α = 0.05). Degradation also was observed for TYL at pH 2 …

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Review Of Design Guidelines For Frp Confinement Of Reinforced Concrete Columns Of Noncircular Cross Sections, Silvia Rocca, Nestore Galati, Antonio Nanni Jan 2008

Review Of Design Guidelines For Frp Confinement Of Reinforced Concrete Columns Of Noncircular Cross Sections, Silvia Rocca, Nestore Galati, Antonio Nanni

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Current international design guidelines provide predictive design equations for the strengthening of reinforced concrete (RC) columns of both circular and prismatic cross sections by means of fiber-reinforced polymer (FRP) confinement and subjected to pure axial loading. Extensive studies (experimental and analytical) have been conducted on columns with circular cross sections, and limited studies have been conducted on members with noncircular cross sections. in fact, the majority of available research work has been on small-scale, plain concrete specimens. in this review paper, four design guidelines are introduced, and a comparative study is presented. This study is based on the increment of …

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