Architecture Commons^™

Influence Of Portland Cement And Ground-Granulated Blast-Furnace Slag On Bleeding Of Fresh Mix, Hong Jae Yim, Jae Hong Kim, Seong Ho Han, Hyo Gyoung Kwak

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Bleeding occurs when freshly mixed cement-based materials settle in a form, and this phenomenon influences the quality of the fresh state as well as the hardened state. This paper attempts to measure the bleeding of Portland cement and ground granulated blast furnace slag (GGBFS) paste mixtures. To investigate the influence of water-to-powder ratio and the used powders under high pressure on bleeding, a pressure vessel and various types of freshly mixed paste were prepared. The packing density and permeability were measured and discussed to understand material effects on the bleeding phenomenon.

Consolidation-Induced Solute Transport For Constant Rate Of Strain. Ii: Comparison With Incremental Loading, Patrick J. Fox, Hefu Pu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a numerical investigation of one-dimensional large strain consolidation-induced solute transport for incremental loading (IL) and constant rate of strain (CRS) conditions. Solute transport accounts for advection, diffusion, dispersion, linear and nonlinear sorption, and equilibrium and nonequilibrium sorption, and is consistent with temporal and spatial variations of porosity and seepage velocity in the consolidating soil. Simulations were conducted using material properties for kaolinite clay and indicate that IL and CRS conditions produce significantly different responses during the course of consolidation, including applied stress, rate of settlement, excess pore pressure, and local strain. However, for a given set of …

Consolidation-Induced Solute Transport For Constant Rate Of Strain. I: Model Development And Simulation Results, Hefu Pu, Patrick J. Fox

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A numerical model, called CSTCRS1, is presented for coupled one-dimensional consolidation and solute transport under constant rate of strain (CRS) loading conditions. The consolidation algorithm accounts for vertical strain, general constitutive relationships, relative fluid velocity, changing compressibility and hydraulic conductivity during consolidation, and an external hydraulic gradient. The solute transport algorithm accounts for advection, dispersion, linear and nonlinear sorption, and equilibrium and nonequilibrium sorption. Soil compressibility is rate-independent and as such CSTCRS1 is more appropriate for less-structured soils. The model is based on a dual-Lagrangian framework that separately tracks the motions of sold and fluid phases. The development of CSTCRS1 …

The Bridge Newsletter Spring 2015, Missouri University Of Science And Technology

The Bridge Newsletter

-Wastewater treatment technologies that cost less and save energy
-Open windows and air quality
-Bartels displays research
-NASA honors Schonberg

The 2014 François Naftali Frenkiel Award For Fluid Mechanics, Benjamin D. Mater, Simon M. Schaad, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

A Shear-Based Parameterization Of Turbulent Mixing In The Stable Atmospheric Boundary Layer, Jordan M. Wilson, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, shear-based parameterizations of turbulent mixing in the stable atmospheric boundary layer (SABL) are proposed. A relevant length-scale estimate for the mixing length LM of the turbulent momentum field is constructed from the turbulent kinetic energy Ek and the mean shear rate S as. Using observational data from two field campaigns-the Surface Heat Budget of the Arctic Ocean (SHEBA) experiment and the 1999 Cooperative Atmosphere-Surface Exchange Study (CASES-99)- is shown to have a strong correlation with LM. The relationship between LM and corresponds to the ratio of the magnitude of the tangential components of the turbulent momentum flux …

Hydraulic Design Of Baffles In Disinfection Contact Tanks, Zachary H. Taylor, Jeremy S. Carlston, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study focuses on understanding the hydraulic design of baffled contact tanks using computational fluid dynamics simulations. In particular, we address the key question: for a given footprint of a rectangular tank with a specified inlet width (Winlet), how does the hydraulic efficiency of a baffled tank depend on the configuration of internal baffles? In an effort to address this question, a carefully conceived parametric study consisting of 30 high-resolution two-dimensional (planar) simulations was conducted to quantify the hydraulic efficiency of a laboratory scale tank as a function of dimensional relationships between key baffle design dimensions (baffle opening length Lbo, …

Comparisons Of Horizontal-Axis Wind Turbine Wake Interaction Models, Jordan M. Wilson, Cole J. Davis, Subhas K. Venayagamoorthy, Paul R. Heyliger

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, Reynolds-averaged Navier-Stokes (RANS) simulations are performed using the k-ϵ and k-ω shear stress transport (SST) turbulence closure schemes to investigate the interactions of horizontal-axis wind turbine (HAWT) models in the neutrally stratified atmospheric boundary layer (ABL). A comparative study of actuator disk, actuator line, and full rotor models of the National Renewable Energy Laboratory (NREL) 5 MW reference turbine is presented. The open-source computational fluid dynamics (CFD) code open foam 2.1.0 and the commercial software ANSYS fluent 13.0 are used for simulations. Single turbine models are analyzed for turbulent structures and wake resolution in the downstream region. …

Biases In Thorpe-Scale Estimates Of Turbulence Dissipation. Part I: Assessments From Large-Scale Overturns In Oceanographic Data, Benjamin D. Mater, Subhas K. Venayagamoorthy, Louis St Laurent, James N. Moum

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Oceanic density overturns are commonly used to parameterize the dissipation rate of turbulent kinetic energy. This method assumes a linear scaling between the Thorpe length scale LT and the Ozmidov length scale LO. Historic evidence supporting LTLO has been shown for relatively weak shear-driven turbulence of the thermocline; however, little support for the method exists in regions of turbulence driven by the convective collapse of topographically influenced overturns that are large by open-ocean standards. This study presents a direct comparison of LT and LO, using vertical profiles of temperature and microstructure shear collected in the Luzon Strait-a site characterized by …

The Formation And Fate Of Internal Waves In The South China Sea, Matthew H. Alford, Thomas Peacock, Jennifer A. Mackinnon, Jonathan D. Nash, Maarten C. Buijsman, Luca A. Centurioni, Shenn-Yu Chao, Ming-Huei Chang, David M. Farmer, Oliver B. Fringer, Ke-Hsien Fu, Patrick C. Gallacher, Hans C. Graber, Karl R. Helfrich, Steven M. Jachec, Christopher R. Jackson, Jody M. Klymak, Dong S. Ko, Sen Jan, T. M. Shaun Johnson, Sonya Legg, I-Huan Lee, Ren-Chih Lien, Matthew J. Mercier, James N. Mourn, Ruth Musgrave, Jae-Hun Park, Andrew I. Pickering, Robert Pinkel, Luc Rainville, Steven R. Ramp, Daniel L. Rudnick, Sutanu Sarkar, Alberto Scotti, Harper L. Simmons, Louis C. St. Laurent, Subhas Karan Venayagamoorthy, Yu-Huai Wang, Joe Wang, Ying J. Yang, Theresa Paluszkiewicz, Tswen-Yung David Tang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis¹, sediment and pollutant transport² and acoustic transmission³; they also pose hazards for man-made structures in the ocean⁴. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometers from their sources before breaking⁵, making it …

Flexural Behavior Of High-Volume Fly Ash Concrete Beams: Experimental Study, Mahdi Arezoumandi, Carlos A. Ortega, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

An experimental investigation was conducted to study both mechanical properties and the flexural strength of full-scale reinforced concrete beams constructed with both high-volume fly ash concrete-concrete with 70% of the cement replaced with fly ash-and conventional concrete (CC). The beams were tested under a simply supported four-point loading condition. The experimental cracking, yielding, and ultimate moments as well as deflection on ultimate load of the beams were compared with both the ACI 318-11 and Eurocode 2-05 provisions. Furthermore, the experimental flexural strengths of the beams were compared with both the modified compression field theory method and a flexural test database …

Evaluation Of An Improved Technique For Geosynthetic-Reinforced And Pile-Supported Embankment, Jun Zhang, Shao Wen Liu, He Fu Pu

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With a large number of applications of conventional technique for geosynthetic-reinforced and pile-supported (GRPS) embankment (called CT embankment), many deficiencies have been exposed. In view of the deficiencies, an improved technique, fixed-geosynthetic-reinforced and pile-supported embankment (called FGT embankment), is developed. To investigate the performance of the FGT embankment, the comparison analyses and parametric studies are conducted by Finite Element Method (FEM). The influencing factors investigated include elastic modulus of soil, tensile stiffness of geosynthetics, pile length, pile spacing, and pile elastic modulus. In addition, the cost evaluation for the FGT embankment and CT embankment is also made. The results show …

Development Of Composite Pcms By Incorporation Of Paraffin Into Various Building Materials, Shazim Ali Memon, Wenyu Liao, Shuqing Yang, Hongzhi Cui, Syed Farasat Ali Shah

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this research, we focused on the development of composite phase-change materials (CPCMs) by incorporation of a paraffin through vacuum impregnation in widely used building materials (Kaolin and ground granulated blast-furnace slag (GGBS)). The composite PCMs were characterized using environmental scanning electron microscopy (ESEM), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Moreover, thermal performance of cement paste composite PCM panels was evaluated using a self-designed heating system. Test results showed that the maximum percentage of paraffin retained by Kaolin and GGBS was found to be 18% and 9%, respectively. FT-IR results show that …

Performance Analysis And Modelling Of Hybrid Photovoltaic-Thermal Solar Panels, Nicole C. Annis

Doctoral Dissertations

A photovoltaic-thermal (PVT) panel was constructed, tested, and modelled using both MATLAB and TRNSYS. During the experimental testing, which took place on the Missouri University of Science and Technology campus in Rolla, Missouri; two identical PVT panels were tested alongside two PV panels to gather an electrical baseline for comparison. Approximately 69 days’ worth of data were of data were collected during the summer of 2014. The PV electrical, PVT electrical, PVT thermal and PVT combined (electrical and thermal) efficiencies were 3.5-5.6%, 3.4-5.4%, 20.9-11.6%, and 24.3-17.0%, respectively.

A MATLAB program was developed using existing equations for one-dimensional, quasi-steady model of …

Model For Consolidation Analysis Of Layered Soils Under Depth-Dependent Loading, Hefu Pu, Patrick J. Fox

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A numerical model is presented for one-dimensional large strain consolidation of a layered soil stratum. The algorithm accounts for vertical strain, soil self-weight, conventional constitutive relationships, changing material properties during consolidation, unload/reload, time-dependent loading and boundary conditions, an externally applied hydraulic gradient, and multiple soil layers with different material properties. The model can also accommodate depth-dependent loading and variable preconsolidation stress profiles. Verification checks of the model show excellent agreement with available analytical and numerical solutions for consolidation of soils with multiple layers and depth-dependent loading. An overview of this model is presented, and a parametric study is performed to …

Effect Of Fly Ash Replacement Level On The Bond Strength Of Reinforcing Steel In Concrete Beams, Mahdi Arezoumandi, Trevor J. Looney, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study compares the bond strength of reinforcing steel in high-volume fly ash concrete (HVFAC) mixes. Three mixes with 0% (conventional concrete), 50%, and 70% replacement of Portland cement with a Class C fly ash investigated in this study. Three beams (simply supported four-point loading condition) as well as three pull-out specimens (based on RILEM recommendations) were tested for each mix. Test results evaluated based on different codes as well as a bond database of conventional concrete specimens. These comparisons indicate that with increasing replacement level of fly ash in concrete the bond strength of reinforcing steel in concrete increases. …

2015 Scholarly Productivity Report, Missouri University Of Science And Technology

Civil, Architectural and Environmental Engineering Scholarly Productivity Reports

No abstract provided.

A Revisit Of The Equilibrium Assumption For Predicting Near-Wall Turbulence, Farid Karimpour, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, we revisit the consequence of assuming equilibrium between the rates of production (P) and dissipation (∈) of the turbulent kinetic energy (k) in the highly anisotropic and inhomogeneous near-wall region. Analytical and dimensional arguments are made to determine the relevant scales inherent in the turbulent viscosity (νt) formulation of the standard k-∈ model, which is one of the most widely used turbulence closure schemes. This turbulent viscosity formulation is developed by assuming equilibrium and use of the turbulent kinetic energy (k) to infer the relevant velocity scale. We show that such turbulent viscosity formulations are not suitable …

Laminar And Turbulent Regime Changes In Drinking Water Contact Tanks, Taylor C. Barnett, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Transitions in flow regimes that can occur in drinking water contact tanks may significantly affect the disinfection efficiency of the system. To demonstrate these effects, the authors investigated the internal velocity fields and flow regime of a drinking water contact tank located in Jamestown, Colo. The baffling factor (BF) of the system fluctuated annually between 0.5 and 0.6 because of a shift in flow regime caused by changes in the flow rate of the system. The authors studied the effects of the regime change from laminar to turbulent flow (or vice versa) using computational fluid dynamics (CFD) models and physical …

Phytoscreening: A Comparison Of In Planta Portable Gc-Ms And In Vitro Analyses, Matt A. Limmer, Gregory D. Martin, Christopher J. Watson, Camilo Martinez, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Phytoscreening Has Been Proven to Rapidly Delineate Subsurface Contaminant Plumes for Semiquantitative Site Assessment, with Minimal Impact to Property or Ecology through the Collection and Analysis of Tree Cores. Here, Three Phytoscreening Methods Were Applied Concurrently to Identify Multiple Chlorinated Volatile Organic Compounds (CVOCs) in a Phytoremediation Treatment System at a Contaminated Industrial Facility. Tree Coring, in Planta Gas Chromatography-Mass Spectrometry (GC-MS), and in Planta Passive Sampling Showed General Agreement, with the in Planta GC-MS Providing the Quickest But Least Quantitative Results. the Portable GC-MS Sampling and Analysis Method Identified Six CVOCs in the Xylem of Hybrid Poplars (Populus Sp.) …

Factors Affecting The Seismic Behavior Of Segmental Precast Bridge Columns, Haitham Dawood, Mohamed Elgawady, Joshua Hewes

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This manuscript discusses the design parameters that potentially affect the lateral seismic response of segmental precast post-tensioned bridge piers. The piers consist of precast circular cross section segments stacked one on top of the other with concentric tendons passing through ducts made in the segments during casting. The bottommost segments of the piers were encased in steel tubes to enhance ductility and minimize damage. An FE model was used to investigate different design parameters and how they influence the lateral force — displacement response of the piers. Design parameters investigated included the initial post-tensioning stress as a percentage of the …

Finite Element Modelling And Dilation Of Frp-Confined Concrete Columns, Osama Youssf, Mohamed Elgawady, Julie E. Mills, Xing Ma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Concrete dilation is one of the main parameters that controls the stress-strain behavior of confined concrete. Several analytical studies have been carried out to predict the stress-strain behavior of concrete encased in fiber-reinforced polymer (FRP), which is crucial for structural design. However, none of these studies have provided a simple formula to determine the dilation parameter that is always required in the finite element (FE) material modelling of concrete. This paper presents a simple empirical model predicting the confined concrete dilation parameter within the theoretical framework of a Karagozian and Case type concrete plasticity model. A set of 105 FRP-confined …

The Bridge Newsletter Winter 2014, Missouri University Of Science And Technology

The Bridge Newsletter

-Smart living
-Bodapati earns lifetime award
-TMS honors Myers
-Mays receives award for research

Phytomonitoring Of Chlorinated Ethenes In Trees: A Four-Year Study Of Seasonal Chemodynamics In Planta, Matt A. Limmer, Amanda J. Holmes, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Long-Term Monitoring (LTM) of Groundwater Remedial Projects is Costly and Time-Consuming, Particularly When using Phytoremediation, a Long-Term Remedial Approach. the Use of Trees as Sensors of Groundwater Contamination (I.e., Phytoscreening) Has Been Widely Described, Although the Use of Trees to Provide Long-Term Monitoring of Such Plumes (Phytomonitoring) Has Been More Limited Due to Unexplained Variability of Contaminant Concentrations in Trees. to Assess This Variability, We Developed an in Planta Sampling Method to Obtain High-Frequency Measurements of Chlorinated Ethenes in Oak (Quercus Rubra) and Baldcypress (Taxodium Distichum) Trees Growing above a Contaminated Plume during a 4-Year Trial. the Data Set Revealed …

Effect Of Placement Characteristics On Scc Lateral Pressure Variations, A. F. Omran, Y. M. Elaguab, Kamal Khayat

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Lateral pressure exerted by fresh concrete on vertical formwork systems controls significantly the design of the formwork systems. Several factors including, material properties, placement conditions, and formwork characteristics can affect formwork lateral pressure. This paper presents the results of an extensive experimental work aimed at studying the influence of concrete temperature (10-32 °C), casting depth (up to 13 m), placement rate (2-30 m/h), waiting period between successive lifts, as well as concrete thixotropy on lateral pressure characteristics. The increase of concrete temperature is shown to accelerate the stiffening rate of the concrete leading to reduction in initial lateral pressure. For …

Measurement Of Stiffness Anisotropy In Kaolinite Using Bender Element Tests In A Floating Wall Consolidometer, X. Kang, G. C. Kang, B. Bate

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

A new floating wall consolidometer-type bender element testing system was developed to study the stiffness anisotropy of clays at applied vertical stresses up to 800 kPa. One-dimensional slurry-consolidated Georgia RP-2 kaolinite samples, prepared with 0.005 and 1 mol/l NaCl solutions, were tested in this system. A floating wall design eliminated the detrimental bending moment that acts upon the horizontally installed benders as a result of soil settlement in a traditional fixed wall setup, which significantly improved the signal quality and bender reuse. Floating wall-soil interface resistance was quantified with pulling tests. Analytical equations were then derived to calculate the wall …

The Quest For An Unambiguous Parameterization Of Mixing Efficiency In Stably Stratified Geophysical Flows, Benjamin D. Mater, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Estimates of turbulent mixing in geophysical settings typically depend on the efficiency at which shear-driven turbulence mixes density across isopycnals. To date, however, no unifying parameterization of diapycnal mixing efficiency exists due to the variability of natural flows and also due to certain ambiguities that arise from descriptions based on a single parameter. Here we highlight important ambiguities of some common single-parameter schemes in the context of a multiparameter framework that considers the independent effects of shear, buoyancy, and viscosity. Parameterizations based on the gradient Richardson number (Ri), the turbulent Froude number (FrT), and the buoyancy Reynolds number (Reb) are …

Effects Of Tendon Spacing On In-Plane Behavior Of Posttensioned Masonry Walls, Dongun Ryu, Anil C. Wijeyewickrema, Mohamed A. Elgawady, M. A.K.M. Madurapperuma

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In-plane behavior of unbonded posttensioned clay brick masonry walls are investigated using detailed finite-element (FE) models. FE models of three walls having different aspect ratios of 1.50, 1.00, and 0.67 are developed. Effects of tendon spacing on in-plane behavior of these walls are investigated using different tendon spacings ranging from 0.61 m (2 ft) to 3.81 m (12.5 ft). In addition, the effects of having different horizontal reinforcement ratios of 0%, 0.1%, and 0.5% on the in-plane behavior of the walls were investigated. The stresses in the tendons are calculated using different approaches, and then the flexural strength of each …

A Unifying Framework For Parameterizing Stably Stratified Shear-Flow Turbulence, Benjamin D. Mater, Subhas Karan Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

An alternative framework for parameterizing stably stratified shear-flow turbulence is presented. Using dimensional analysis, four non-dimensional parameters of interest are identified that consider the independent effects of stratification, shear, viscosity, and scalar diffusivity. In the interest of geophysical applications, the problem is further simplified by considering only high Reynolds number flow. This leads to a two-dimensional parameter space based on a buoyancy strength parameter (i.e., an inverse Froude number) and a shear strength parameter. Consideration for the gradient Richardson number allows the space to be divided into an unforced regime, a shear dominated regime, and a buoyancy-dominated regime. On this …

A Comparative Study Of The Mechanical Properties, Fracture Behavior, Creep, And Shrinkage Of Chemically Based Self-Consolidating Concrete, Mahdi Arezoumandi, Mark Ezzell, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This study presents the results of an experimental investigation that compares the mechanical properties, fracture behavior, creep, and shrinkage of a chemically based self-consolidating concrete (SCC) mix with that of a corresponding conventional concrete (CC) mix. The CC and SCC mix designs followed conventional proportioning in terms of aggregate type and content, cement content, air content, water-cementitious materials (w/cm) ratio, and workability. Then, using only chemical admixtures, the authors converted the CC mix to an SCC mix with all of the necessary passing, filling, flowability, and stability requirements typically found in SCC. The high fluidity was achieved with a polycarboxylate-based …