Architectural Engineering Commons^™

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 …

Thickening: A 21st Century Approach For Resilience In Infrastructure, Marco Antonio Ravini

Architecture Thesis Prep

Infrastructure should be designed for higher RESILIENCE, not permanence. Rather than over-engineer to resist the inevitable failure of individual components, the next generation of public infrastructure needs to exceed its technical specifications and seek opportunistic hybridity between systems. In doing so, new possibilities for multi-layered use/outputs emerge which contribute to a more productive and resilient infrastructural lifespan.

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.) …

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 …

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 …

Designing Acoustics For Linguistically Diverse Classrooms: Effects Of Background Noise, Reverberation And Talker Foreign Accent On Speech Comprehension By Native And Non-Native English-Speaking Listeners, Z. Ellen Peng

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

The current classroom acoustics standard (ANSI S12.60-2010) recommends core learning spaces not to exceed background noise level (BNL) of 35 dBA and reverberation time (RT) of 0.6 second, based on speech intelligibility performance mainly by the native English-speaking population. Existing literature has not correlated these recommended values well with student learning outcomes. With a growing population of non-native English speakers in American classrooms, the special needs for perceiving degraded speech among non-native listeners, either due to realistic room acoustics or talker foreign accent, have not been addressed in the current standard. This research seeks to investigate the effects of BNL …

Determining Thresholds Of Annoyance To Tones In Noise, Jennifer Marie Francis

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

Building services equipment often produce noise with prominent tones that can lead to complaints from occupants in the built environment. Previous studies have investigated human perception to tones in noise but it is still unclear at what threshold of prominence these tones lead to human annoyance. The goal of this research is to apply two different methods towards defining thresholds of annoyance to two tonal frequencies: 125 Hz and 500 Hz. In Method I – Direct Assessment with Task, subjects are exposed to 10 minutes of broadband noise with a tonal frequency set at a certain level of prominence while …

Impacts Of Climate Change On Urban Development In The Uae: The Case Of Dubai, Zainab Alrustamani Alrustamani

Theses

This thesis investigates the global calls to prepare for climate change impacts, and the role of cities to respond to it under their sustainable living approaches. It explores how the subject of climate change is integrated in the urban development process, highlighting the role of cities as contributors to the phenomenon and part of the solution. The response to climate change impacts was explored in the UAE and the emirate of Dubai. The main objective of this research is to highlight the future vision in action against climate change in the urban development framework of the emirate of Dubai, and …

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 …

Assessment Of Noise-Induced Annoyance By Tones In Noise From Building Mechanical Systems, Joonhee Lee, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

Prominent tones in noise generated by mechanical equipment in buildings can cause complaints from occupants in buildings. The ISO 1996-2 and ANSI S1.13 standards describe methodologies and metrics to quantify tonality perception, but the influence of tones in noise on human annoyance and performance is not fully understood yet. This paper investigates annoyance responses of humans while exposed to background noise with tonal components. Twenty participants completed digit span tasks while exposed to noise signals with differing levels of tones and overall loudness. Subjects were also asked to rate their annoyance after completing tasks under each noise signal. The subjective …

The Impact Of Building Acoustics On Speech Comprehension And Student Achievement, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

The movement for improved classroom acoustics has primarily been grounded on studies that show how building acoustics (i.e. background noise levels and room reverberation) affect speech intelligibility, as determined by speech recognition tests. What about actual student learning, though? If students do not understand each spoken word in the classroom perfectly, can they still manage to achieve high scholastic success? This presentation will review two recent studies conducted at the University of Nebraska – Lincoln, linking classroom acoustic conditions to student learning outcomes and speech comprehension (rather than simply recognition). In the first, acoustic measurements in two public school districts …

Effects Of Room Acoustics On Comprehension Of Foreign-Accented Speech By Native And Non-Native English-Speaking Listeners, Zhao Peng, Kristin E. Hanna, Brenna N. Boyd, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

In a previous study by the authors, reverberation time (RT) and background noise level (BNL) were both found to have negative effects on native and non-native English-speaking listeners in comprehending English speech produced by native American-English-speaking talkers. Comprehension scores were adjusted for listeners’ baseline English proficiency levels. In the present study, instead of native English-speaking talkers, two native Mandarin Chinese talkers (one male, one female) with similar English spoken proficiency were recruited to produce the same speech materials used in the previous study. A similar methodology was adopted to conduct speech comprehension tests on three groups of listeners: 1) native …

Ua66 Ogden College Of Science & Engineering Newsletter, Cheryl Stevens, Dean

Ogden College of Science & Engineering Publications

No abstract provided.

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

Designing And Constructing For A Sustainable Future: Community Urban Housing In Timber: Projects By 4th. Year Architecture Students At Dit, Jim Roche

Conference papers

There is some agreement and much debate among interested parties about what constitutes ‘sustainable housing’. The term ‘sustainable’ is used somewhat liberally to mean different things to different listeners. Governments, institutions, interest groups and individual designers often address certain aspects while ignoring the bigger picture. But the bigger picture is such a multivalent issue that includes aspects outside the architect’s immediate remit such as location, transport, security, procurement policy and post-occupancy analysis and management. Or are these outside the architect’s remit?

Teaching sustainable housing within conventional architecture programmes means educators are restricted to identifying certain key issues that students should …

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 …

Evaluating Existing And Proposing New Seismic Design Provisions For Rigid Wall - Flexible Diaphragm Buildings, John Lawson, Dominic Kelly, Maria Koliou, Andre Filiatrault

Architectural Engineering

Buildings with heavy concrete on masonry walls supported by flexible wood or steel deck roof diaphragms are ubiquitour across the United States and the rest of North America. The current seismic design approach is based on the equivalent lateral force (ELF) method whose underlying assumptions significantly differ from the actual dynamic response of these buildings. The seismic behavior of rigid wall-flexible rood diaphragm (RWFD) Buildings is dominated by the diaphragm's response instead of the wall' in-plane response. Furthermore, the diaphragm's ductility and overstrength capacity is unique to its own construction. Yet the current design methodology employed by practitioners directly ties …

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 …

Distribution Of Chord Forces In Large Panelized Wood Roof Diaphragms, Weichang Pang, Chun Ni, John Lawson, Sami Pant

Architectural Engineering

Flexible wood roof diaphragms are very common in the United States, both for residential buildings and large-scale commercial buildings. Due to its simplicity, the traditional diaphragm design method is commonly used in diaphragm design, in particular for the design of diaphragms with relatively small dimensions. The traditional diaphragm design method assumes the axial chord forces developed in framing members under in-plane loading are carried only by the perimeter elements. This method has always been thought to be a conservative design method, especially when applied to large diaphragms. In recent years, the engineering community began to question the applicability of the …

Examining The Applicability Of Design Methods For Large Panelized All-Wood Roof Diaphragms Under Seismic Loading, W. Pang, S. Pant, C. Ni, John W. Lawson

Architectural Engineering

The use of flexible roof diaphragms is very common in the United States, both for residential buildings and large-scale commercial buildings. Due to its simplicity, the traditional diaphragm design method is commonly used in diaphragm design, in particular for the design of diaphragms with relatively small dimensions. The traditional diaphragm design method assumes the axial chord forces developed in framing members under in-plane loading are carried only by the perimeter elements. The traditional diaphragm design method has always been thought to be a conservative design method, especially when applied to large diaphragms. In recent years, the engineering community began to …

Numerical Framework For Seismic Collapse Assessment Of Rigid Wall-Flexible Diaphragm Structures, M. Koliou, A. Filiatrault, D.J. Kelly, John W. Lawson

Architectural Engineering

This study focuses on the development of a two dimensional (2D) simplified numerical framework of rigid wall-flexible diaphragm (RWFD) structures that can be used to validate seismic design approaches. This type of low-rise industrial buildings, which is widely used in North America, incorporates rigid in-plane concrete or masonry walls and flexible in-plane wood, steel or “hybrid” roof diaphragms. The numerical modeling is detailed enough to capture the nonlinear seismic response of RWFD buildings, but simplified enough to efficiently conduct a large number of nonlinear time-history dynamic analyses. The 2D numerical modeling framework is based on a three step sub-structuring approach …

Development Of Seismic Design Methodologies For Rigid Wall-Flexible Diaphragm Structures, John W. Lawson, D. J. Kelly, M. Koliou, A. Filiatrault

Architectural Engineering

Evidence indicates that the dynamic behavior of Rigid Wall – Flexible Diaphragm (RWFD) structures is dominated by the diaphragm’s response instead of the walls’ response, and this is a significant departure from the underlying assumptions of the widely used equivalent lateral force method in current building codes. RWFD buildings are common in North America and other parts of the world, and incorporate rigid in-plane concrete or masonry walls and flexible in-plane wood or steel roof diaphragms. With the use of a numerical computer modeling framework developed specifically for this type of building, this study sets out to investigate the seismic …

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 …

Coastal Defenses, U.S., Bert Chapman

Libraries Faculty and Staff Scholarship and Research

Provides an overview of U.S. military coastal defenses during the period up to and including the War 1812.

An Emerging Vocabulary: Architecture Of Performance, Jeremy H. Stock

Kaleidoscope

Re-chartered at the University of Kentucky in 2005, the Triangle Fraternity – a brotherhood of students studying Architecture, Engineering, and Sciences – now seeks to establish a visible presence by building a new fraternity house on-campus. To enable this investigation, professors Gregory Luhan, Peyman Jahed, and Bruce Walcott developed a design + energy studio experience that provided a framework for an integrated design team to use a systems-thinking approach to generate a range of scalable, net-zero energy prototypes. These prototypes can be applied in a variety of contexts and have the potential to address larger issues, such as energy efficiency …

No Admixture, Sustainable, Self-Consolidating Grout, Craig Baltimore, James P. Mwangi, Eric W. Bateman

Architectural Engineering

The consolidation of grout in concrete masonry unit (CMU) walls is labor-intensive. Also, the grout’s Portland cement content has a high embodied energy demand – a non-sustainable characteristic. For the labor-intensive issue, chemical admixture self-consolidating grouts have been used in walls 12.67 ft. (3.86 m) tall, however the chemical additive can impose new limitations on the grout (non-robust characteristics). No admixture self-consolidating grout with high percentage Portland cement replacement have potential for robust and sustainable application. This paper reports on the consolidation of no admixture self-consolidating grout made by substituting high percentages of Portland cement with Type-F fly ash and/or …

Determining Annoyance Thresholds Of Tones In Noise, Jennifer M. Francis, Joonhee Lee, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

Building services equipment often produces noise signatures with significant tones in them that can lead to complaints in the built environment. Previous studies have investigated prominence levels of assorted tonal frequencies, but it is still unclear what prominence of the tones across varying tonal frequencies can lead to human annoyance. This project seeks to apply two different methods towards defining annoyance thresholds of tones in noise at two tonal frequencies: 125 Hz and 500 Hz. In the first, subjects are asked to perform a task, while exposed to ten minutes of a broadband noise spectrum with a specific level of …

Using K’Nex To Teach Large Scale Structures To Architects And Constructionstudents, Allen C. Estes, Craig Baltimore

Architectural Engineering

The College of Architecture and Environmental Design at California Polytechnic State University in San Luis Obispo (Cal Poly SLO) is the only college in the nation that includes architecture (ARCH), architectural engineering (ARCE) and construction management (CM) programs in the same college. Given the unique mix of disciplines and the emphasis on interdisciplinary collaboration, the ARCH and CM students take a five-course structural engineering sequence from the ARCE department. A challenge of these courses is to maintain some degree of computational rigor while offering a broader perspective that will benefit the ARCH and CM students. This paper reports on one …

New Civil Engineering Program Criteria: How The Sausage Is Being Made, Allen Estes, Thomas A. Lenox

Architectural Engineering

The American Society of Civil Engineers organized the Civil Engineering Program Criteria Task Committee in October 2012 whose charge is to determine if the current ABET Civil Engineering Program Criteria (CEPC) should be changed to reflect one or more of the 24 outcomes of the second edition of the Civil Engineering Body of Knowledge published in 2008. After over a year of conference calls and face to face meetings, the committee has drafted and disseminated a proposed CEPC. This paper chronicles the development of the proposed criteria by sharing a review of the literature, the committee’s methodology and process, the …