Architectural Engineering Commons^™

Some Insights For The Prediction Of Near-Wall Turbulence, Farid Karimpour, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this paper, we revisit the eddy viscosity formulation to highlight a number of important issues that have direct implications for the prediction of near-wall turbulence. For steady wall-bounded turbulent flows, we make the equilibrium assumption between rates of production (P) and dissipation (ε) of turbulent kinetic energy (κ) in the near-wall region to propose that the eddy viscosity should be given by vt ε/S², where S is the mean shear rate. We then argue that the appropriate velocity scale is given by (STL)-1/2 k^1/2 where TL = k ε is the turbulence (decay) time scale. The …

Performance-Based Seismic Design Of Unbonded Precast Post-Tensioned Concrete Filled Gfrp Tube Piers, Haitham M. Dawood, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents a seismic design procedure for self-centering precast post-tensioned bridge piers. The piers presented in this manuscript consisted of concrete filled fiber reinforced polymer (FRP) tubes. A large set of 84 piers with different design parameters were analyzed using finite element models. The backbone curve of each pier was developed and bilinearized. The idealized backbone curves were used to develop a set of empirical equations that were able to reproduce the bilinearized backbone curve of a given pier. Different performance criteria have been proposed for the system according to the intensity and the frequency of occurrence of a …

An Experimental Study On Shear Strength Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

An experimental investigation was conducted to compare the shear strength of full-scale beams constructed with chemically based, self-consolidating concrete (SCC) with conventional concrete (CC). This experimental program consisted of 16 rectangular beams (12 without shear reinforcing and 4 with shear reinforcing in the form of stirrups), 8 beams for each mix design. Additionally, three different longitudinal reinforcement ratios were evaluated within the test matrix. The beam specimens were tested under a simply supported four-point condition. The experimental shear strengths of the beams were compared with both the shear provisions of selected standards (U.S., Australia, Canada, Europe, and Japan) and a …

Effect Of Fly Ash On Growth Of Mustard And Corn, Cailie Carlile, Snehalata Nadiger, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Fly Ash is Generated as a By-Product of Coal Combustion and Contains Many Nutrients, Such as Ca, K, Na, Mg, and S, as Well as Toxic Metals Such as As, B, Cd, Cr, Hg, and Pb. for This Project, the Goal is to Optimize a Phytoremediation Technique to Stabilize the Toxic Metals and Produce Biomass Which Could Have Benefit for Example as Biofuel. the Hypothesis Was that Different Amendments Would Improve the Water Holding Properties of the Ash and Reduce Metals Availability and Toxicity. Flyash Was Combined with Leaf Mulch (1%, 3%, 5%, 10%, 20%), Wood Mulch (1%, 3%, 5%, …

Scale Of Fluctuation Of Geotechnical Parameters Estimated From Cptu And Laboratory Test Data, Site Onyejekwe, Louis Ge

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

For a complete probabilistic characterization of a geotechnical parameter, its mean, variance, and the scale of fluctuation have to be known. While the mean and variance can be easily determined, determination of the scale of fluctuation is a little more complex. Knowledge of the scale of fluctuation is important in reliability-based design as it is used in implementing spatial averaging and computing the variance-reduction factor. Published values of scale of fluctuation of geotechnical parameters are based on widely sourced data and hence may not be most appropriate for local situations. Based on 11 CPTu soundings and laboratory test results of …

Probability Of Failure For Slopes With Sensitivity Analysis, Michelle Deng, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The significance of random variables on the probability of failure of slopes is generally evaluated by changing a different set of values for each variable and repeating the approach several times to conclude a trend. This method is very straightforward but requires time and computational resources; and it is inefficient especially when the number of random variables is large. This paper presents an analysis approach in which the sensitivity analysis is introduced to quantify the influence of the random variables on the probability of failure for slopes. In this study, the factor of safety of the slope was determined using …

Appropriate Viscous Damping For Nonlinear Time-History Analysis Of Base-Isolated Reinforced Concrete Buildings, Deepak R. Pant, Anil C. Wijeyewickrema, Mohamed A. Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

SUMMARY: There is no consensus at the present time regarding an appropriate approach to model viscous damping in nonlinear time-history analysis of base-isolated buildings because of uncertainties associated with quantification of energy dissipation. Therefore, in this study, the effects of modeling viscous damping on the response of base-isolated reinforced concrete buildings subjected to earthquake ground motions are investigated. The test results of a reduced-scale three-story building previously tested on a shaking table are compared with three-dimensional finite element simulation results. The study is primarily focused on nonlinear direct-integration time-history analysis, where many different approaches of modeling viscous damping, developed within …

Wind Loading On Trees Integrated With A Building Envelope, Aly Mousaad Aly, Alberto Zasso, Girma Bitsuamlak, Alberto Nicola Longarini, Arindam Gam Chowdhury

Faculty Publications

With the sustainability movement, vegetated building envelopes are gaining more popularity. This requires special wind effect investigations, both from sustainability and resiliency perspectives. The current paper focuses on wind load estimation on small- and full-scale trees used as part of green roofs and balconies. Small-scale wind load assessment was carried out using wind tunnel testing in a global-effect study to understand the interference effects from surrounding structures. Full-scale trees were investigated at a large open-jet facility in a local-effect study to investigate the wind-tree interaction. The effect of Reynolds number combined with shape change on the overall loads measured at …

An Experimental Study On Bond Strength Of Reinforcing Steel In High-Volume Fly-Ash Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The production of Portland cement-the key ingredient in concrete-generates a significant amount of carbon dioxide. However, because of its incredible versatility, availability, and relatively low cost, concrete is the most consumed manmade material on the planet. One method of reducing concrete's contribution to greenhouse gas emissions is the use of fly ash to replace a significant amount of the cement. an experimental investigation was conducted to compare the bond strength of reinforcing steel in high-volume fly-ash concrete (HVFAC)-concrete with at least 50 % of the cement replaced with fly ash-with conventional concrete (CC). This study investigated two HVFAC mixes [with …

Statistical Modelling Of The Coupled Effect Of Mix Design And Rebar Spacing On Restricted Flow Characteristics Of Scc, Yahia Ammar, Khayat H. Kamal, Sayed Mohammed

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-consolidating concrete (SCC) is designed to exhibit high deformability and stability to maintain homogenous suspension of coarse aggregate particles in the mortar during flow to ensure adequate passing ability of the concrete through restricted areas and the filling of the formwork without any consolidation. Proper deformability and uniform suspension of coarse aggregate particles in the matrix are key parameters to ensure successful casting and adequate in situ performance. the required flow properties of concrete are affected by the rheological properties of the mixture and the characteristics of the cast element, including the level of reinforcement. the mixture proportioning of SCC …

Influencing Factors On The Dynamic Properties Of Organobentonites, Bate Bate, Susan Burns

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The dynamic responses of soils are important engineering properties, especially for soils with high organic contents, because these soils can underlie critical support structures such as highway bridges or levees. Consequently, the initial tangent shear modulus (Gmax), secant shear modulus ratio (G/Gmax), and damping ratio (D) are important parameters in evaluating the dynamic soil behavior for soils subjected to earthquake, wind, waves, traffic, and equipment vibration. in this study, these dynamic properties of organ bentonites were quantified experimentally using resonant column tests. the results from this study were evaluated in terms of the effect of shear strain, organic content, and …

Effect Of Scc Mixture Composition On Thixotropy And Formwork Pressure, A. F. Omran, Kamal H. Khayat, Y. M. Elaguab

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

High lateral pressure exerted on formwork systems by self-consolidating concrete (SCC) is one of the hindrances for using such highly flowable concrete in cast-in-place applications. Self-consolidating concrete is a complex system that can be made using a wide range of mixture proportioning and often incorporated various chemical admixtures and supplementary cementitious materials. the investigation of the effect of each material ingredient independently on lateral pressure of SCC is not a simple task. in this study, thixotropy is rather used to assess the effect of various mixture parameters on formwork pressure. Thixotropy is determined by the evaluation of the structural buildup …

Quantifying The Effect Of Nanoparticles On As(V) Ecotoxicity Exemplified By Nano-Fe2o3 (Magnetic) And Nano-Al2o3, Ji Hu, Demin Wang, Brett E. Forthaus, Jianmin Wang

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Nano-Fe₂O₃ (magnetic) and nano-Al₂O₃ are increasingly used in biomedical fields for cellular labeling and drug delivery, and in the industry as catalysts. However, they may also serve as carriers of toxic contaminants and negatively impact the environment and human health. in the present study, Ceriodaphnia dubia was used to assess the toxicity of these nanoparticles (NPs) with and without the presence of background arsenic(V) (As[V]). the results showed that although these NPs alone did not exhibit significant toxicity in the experimental concentration range, they could significantly enhance the toxicity of As(V). the accumulation of …

Numerical Simulation Of Particle-Driven Gravity Currents, Sangdo An, Pierre Y. Julien, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Particle-driven gravity currents frequently occur in nature, for instance as turbidity currents in reservoirs. They are produced by the buoyant forces between fluids of different density and can introduce sediments and pollutants into water bodies. In this study, the propagation dynamics of gravity currents is investigated using the FLOW-3D computational fluid dynamics code. The performance of the numerical model using two different turbulence closure schemes namely the renormalization group (RNG) k-ε scheme in a Reynold-averaged Navier-Stokes framework (RANS) and the large-eddy simulation (LES) technique using the Smagorinsky scheme, were compared with laboratory experiments. The numerical simulations focus on two different …

The Bridge Newsletter Winter 2012, Missouri University Of Science And Technology

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Computational Modeling Of Baffled Disinfection Tanks, Zachary H. Taylor, Qing Xu, Jordan M. Wilson, Subhas K. Venayagamoorthy

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The present study focuses on understanding the flow dynamics of baffled disinfection contact tanks through the use of computational fluid dynamics (CFD). In particular, we seek to address the key question: for a given footprint of a contact tank with a fixed inlet configuration, how does the hydraulic efficiency of the tank depend on the configuration of internal baffles? The benchmark contact tank geometry in our study is shown in Figure 1. In order to define guidelines for hydraulically efficient baffle tanks, we perform a total of 36 high-resolution three-dimensional simulations to quantify the efficiency of a laboratory scale tank …

Dendrochemistry Of Multiple Releases Of Chlorinated Solvents At A Former Industrial Site, Jean Christophe Balouet, Joel Gerard Burken, Frank Karg, Don Vroblesky, Kevin T. Smith, Håkan Grudd, Anders Rindby, François Beaujard, Michel Chalot

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Trees Can Take Up and Assimilate Contaminants from the Soil, Subsurface, and Groundwater. Contaminants in the Transpiration Stream Can Become Bound or Incorporated into the Annual Rings Formed in Trees of the Temperate Zones. the Chemical Analysis of Precisely Dated Tree Rings, Called Dendrochemistry, Can Be Used to Interpret Past Plant Interactions with Contaminants. This Investigation Demonstrates that Dendrochemistry Can Be Used to Generate Historical Scenarios of Past Contamination of Groundwater by Chlorinated Solvents at a Site in Verl, Germany. Increment Cores from Trees at the Verl Site Were Collected and Analyzed by Energy-Dispersive X-Ray Fluorescence (EDXRF) Line Scanning. the …

Framework For Formative Assessment Learning Strategies In Built Environment Higher Education Programmes, Lloyd Scott, Christopher Fortune

Conference papers

Formative assessment has begun to be recognized as a driving force for enhancing student learning. This paper addresses the context of Built Environment (BE) undergraduate programmes and the findings from a research project in the context of the changing Higher Education (HE) environment. The analysis of the literature on formative assessment shows that there is a common concern among the educational researchers about the function and position of assessment in HE today. The overall aim of this research is to contribute to an improvement in the quality of student learning in BE undergraduate education through the development of a theoretical …

An Experimental Study On Bond Strength Of Reinforcing Steel In Self-Consolidating Concrete, Trevor J. Looney, Mahdi Arezoumandi, Jeffery S. Volz, John J. Myers

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

An experimental investigation was conducted to compare the bond strength of reinforcing steel in self-consolidating concrete (SCC) with conventional concrete (CC). This study investigated two different compressive strengths of SCC as well as CC. the experimental program consisted of 24 pull-out specimens as well as 12 full-scale beams (three for each concrete type and strength). the pull-out specimens were based on RILEM recommendations, and the beam specimens were tested under a simply supported four-point loading condition. the CC test results served as a control and were used to evaluate the results from the SCC pull-out and beam specimen tests. Furthermore, …

Behavior Of Segmental Precast Posttensioned Bridge Piers Under Lateral Loads, Haitham Dawood, Mohamed Elgawady, Joshua Hewes

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Abstract a segmental precast posttensioned (SPPT) bridge pier is an economic recentering structural system. Understanding the seismic behavior of a SPPT system is an important step toward its application in high seismic zones. This paper presents a detailed three-dimensional finite-element (FE) model that was developed using the ABAQUS platform. a brief description and discussion of cyclic tests on eight large-scale SPPT piers is also presented. Four of the piers were constructed and tested to a predefined degree of damage. Then, these piers were retrofitted and retested. the FE models developed and presented in this paper predicted the backbone curves of …

Use Of Building Information Modelling In Responding To Low Carbon Construction Innovations: An Irish Perspective., Barry Mcauley, Alan V. Hore, Roger West

Conference papers

At present the Irish construction industry is facing one of its most uncertain and challenging periods and will see major cuts in all areas of the economy in 2012. Despite this, Ireland pushes forward in sustainability initiatives with the Government ruling that environmentally-friendly policies are to get priority in competing for State contracts worth up to €16 billion a year. This and further initiatives are in place, so as to reduce greenhouse gas emissions by up to 20% by the year 2020.By the end of 2018 the public sector must own or rent only buildings with high energy-saving standards and …

Implementing Building Information Modeling In Public Works Projects In Ireland, Barry Mcauley, Alan V. Hore, Roger West

Conference papers

The Irish State in recent years has suffered huge financial losses in the public works sector, which has now pushed the Irish Government to explore new ways of controlling cost. This background lead to the introduction of the Capital Works Management Framework in 2007 which aimed to support the certainty of outcome in terms of cost and quality, as well as improved risk management, through the implementation of fixed price contracts. In order to successfully compete within this framework it is recommended by the authors, that Irish Government moves towards the legal mandating of BIM. This can ensure a greater …

Behavior Of Full-Scale Rc T-Beams Strengthened In Shear With Externally Bonded Frp Sheets, Abdeldjelil Belarbi, Sang Wook Bae, Antonio Brancaccio

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Recently many research studies have investigated the shear behavior of reinforced concrete (RC) beams strengthened with fiber-reinforced polymer (FRP) composites. However, most were conducted on small-scale specimens. Thus, analytical models and design equations developed from those studies may not predict the actual behavior of large-scale RC beams strengthened with FRPs. in this study, an experimental study was performed on this topic using full-scale RC T-beams in order to understand the behavior of full-scale bridge beams strengthened in shear with FRP. the main parameters investigated in this study were the transverse steel reinforcement ratio and the effect of mechanical anchorage systems. …

Probabilistic Resilience Quantification And Visualization Building Performance To Hurricane Wind Speeds, Berna Eren Tokgoz

Engineering Management & Systems Engineering Theses & Dissertations

Natural and man made disasters are unpredictable and unavoidable in today's world. Their frequency of occurrence and damages keep increasing. Due to the efforts to reduce negative consequences from such disasters, the concept of resilience has gained so much popularity in disaster management area especially after disasters like the September 11 attacks and Hurricane Katrina. Complex systems of today are under operational risks because of increasing threats and their high level of vulnerability. Hence, such systems need to adapt the concept of resilience for continuous operations. Resilience is a proactive concept which should incorporate both pre-event (preparedness and mitigation) and …

Multinomial Logistic Regression Model For Single-Vehicle And Multivehicle Collisions On Urban U.S. Highways In Arkansas, Ghulam Bham, Bhanu S. Javvadi, Uday R.R. Manepalli

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Multivariate analysis can be used to identify the effects of several factors on the causes of a crash compared with univariate analysis. This paper uses a multivariate-analysis technique, the multinomial logistic regression (MLR) model, to examine the differences in crash-contributing factors for six collision types for both divided- and undivided-highway nonjunctions, given that a crash has occurred. Multinomial logistic regression was used to investigate (1) single-vehicle and (2) multivehicle collisions, which included (1) angular, (2) head-on, (3) rear-end, (4) sideswipe-same-direction, and (5) sideswipe-opposite-direction collisions. the risks associated with different collision types were found to be significantly influenced by various vehicle …

Development And Testing Of Chemically-Based Self-Consolidating Concrete, Mahdi Arezoumandi, Mark Ezzell, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

Self-consolidating concrete (SCC) has the potential to significantly reduce costs associated with concrete construction. SCC is a highly flowable, Non segregating concrete that has a variety of advantages over conventional concrete (CC). However, SCC is not without its problems, which can include increased creep and shrinkage, as well as decreased bond and shear strength. the goal of this research project was to evaluate the creep, shrinkage, and shear behavior of a chemically Based SCC mix. One of the benefits of a chemically Based approach is the potential to eliminate the negative side effects of many SCC mixes. the investigation included …

High-Volume Fly Ash Concrete For Sustainable Construction, Jeffery S. Volz

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

With worldwide production of fly ash approaching 800 million tons annually, increasing the amount of fly ash used in concrete will remove more material from the solid waste stream and reduce the amount ending up in landfills. However, most specifications limit the amount of cement replacement with fly ash to less than 25 or 30%. Concrete with fly ash replacement levels of at least 50% - referred to as high-volume fly ash (HVFA) concrete - offers a potential green solution. the following study investigated the structural performance of HVFA concrete compared to conventional Portland-cement concrete. Specifically, the research examined both …

Performance-Based Analysis Of A Reinforced Concrete Shear Wall Building, Garrett Richard Hagen

Master's Theses

PERFORMANCE-BASED ANALYSIS OF A REINFORCED CONCRETE SHEAR WALL BUILDING

Garrett Richard Hagen

In this thesis, a special reinforced concrete shear wall building was designed per ASCE 7-05, and then the performance was investigated using the four analysis procedures outlined in ASCE 41-06. The proposed building was planned as a 6-story office building in San Francisco, CA. The structural system consisted of a two-way flat plate and reinforced concrete columns for gravity loads and slender structural walls for seismic loads. The mathematical building models utilized recommendations from ASCE 41-06 and first-principle mechanics. Moment-curvature analysis and fiber cross-section elements were used in …

Structural Performance Of Reinforced Concrete Flat Plat Buildings Subjected To Fire, Sara Jean George

UNLV Theses, Dissertations, Professional Papers, and Capstones

Reinforced concrete structures are typically considered to have inherent resistance to fire. However, several concrete structures around the world have experienced partial or total collapse under fire. Reinforced concrete flat-plate is a type of structural system widely used for office and residential buildings. Flat plate construction is prone to punching shear failure at slab-column connections which may lead to a catastrophic progressive collapse. The slabs of flat-plates generally have very thin concrete cover leaving steel reinforcement more sensitive to thermal loads. Little is known in the engineering community about the structural performance of flat-plate structures subjected to fire. Through a …

Monotonic Behavior Of Mississippi River Valley Silt In Triaxial Compression, Shuying Wang, Ronaldo Luna

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

The static behavior of Mississippi River Valley silt was characterized using triaxial compression testing. Silt specimens, especially over consolidated ones, showed dilation behavior. There was no unique critical state among specimens with different over consolidation ratios (OCRs). with OCRs of 1, 2, and 8, the specimens exhibited normal behavior and dilated more as effective consolidation pressure dropped. However, for an OCR of 4, the specimens showed opposite behavior and dilated more as effective consolidation pressure rose. the friction angle of the silt was computed on the basis of several failure criteria, and the limiting strain was found to be the …