Other Engineering Commons^™

Availability Heuristic In Construction Workforce Decision-Making Amid Covid-19 Pandemic: Empirical Evidence And Mitigation Strategy, Yunping Liang, Anil Baral, Mohsen Shahandashti, Baabak Ashuri

Durham School of Architectural Engineering and Construction: Faculty Publications

The decision-making situations of the construction workforce have been drastically altered since the outbreak of the Coronavirus 2019 (COVID-19) pandemic. The new situation, where decision-makers strive to promptly respond to the unprecedented crisis to sustain essential construction operations without compromising the safety and health of workers, implies the presence of an availability heuristic. An availability heuristic has the potential to bring unconscious, systematic errors to the decision-making process. This study creates a decision-making experiment to empirically examine the presence of an availability heuristic and the effectiveness of a corresponding mitigation strategy in construction workforce decision-making under COVID-19 uncertainties. The experiment …

Impact Of Covid-19 On The Diversity Of The Construction Workforce, Anil Baral, Yunping Liang, Mingshu Li, Marilyn Gonzalez, Mohsen Shahandashti, Baabak Ashuri

Durham School of Architectural Engineering and Construction: Faculty Publications

Construction industry employment has been severely impacted by the coronavirus (COVID-19) pandemic. This paper examines the impact of the COVID-19 pandemic in the US construction labor market. This study contributes to the state of knowledge by (1) revealing how the COVID-19 pandemic impacted construction employment across different demographic groups and geographic regions in the US, and (2) identifying vulnerable demographic groups (e.g., minorities, women, older workers) in the construction workforce that are disproportionally impacted by the pandemic. Employment data from the Current Population Survey and Current Employment Statistics (CES) programs, which are administered by the Bureau of Labor Statistics, are …

Tilt-Up Partially Composite Insulated Wall Panels, Marc Maguire, Salam Al-Rubaye

Durham School of Architectural Engineering and Construction: Faculty Publications

This research project was initiated to investigate the behavior of load-bearing concrete insulated wall panels for use in tilt-up construction. The primary objective was to understand the inelastic behavior of these panels so that engineers could perform a proper second-order analysis for combined axial and out-of-plane loading. Toward this aim, the Tilt-up Concrete Institute (TCA) and wythe connector suppliers Innstruct, Thermomass, HK Composites, Dayton Superior, and IconX, funded this study.

This report contains information related to testing of solid and partially composite insulated wall panels that integrated proprietary wythe connection systems. Using the information from these tests, a method to …

Challenges And Enabling Features Of Small And Medium Infrastructure Public-Private Partnerships (P3s): A Case Study Of The Us P3 Infrastructure Market, Yunping Liang, Baabak Ashuri

Durham School of Architectural Engineering and Construction: Faculty Publications

Purpose: In classical perspective, projects under a certain size are not feasible for P3. However, there is an emerging trend on using P3 to deliver projects that are frequently small to medium sized to meet ever-increasingly complex social needs, including enhancing lifecycle performance of existing facilities, designing and building for resilience and sustainability, ensuring cost effectiveness of public spending, and fostering innovation. In contrast with the increasing implementation, small and medium P3s, especially those in the United States, receive little attention in existing studies. This study aims at answering the question: in the context of the US, what features of …

The Application Of Mathematical Optimization And Flavor-Detection Technologies For Modeling Aroma Of Hops, Yutong Liu

Department of Food Science and Technology: Dissertations, Theses, and Student Research

In recent years, proprietary hops (Citra, Simcoe, and Mosaic) become the most sought-after hops among brewers due to their excellent aroma. However, they are restricted to the owners unless other growers purchase the costly licensing agreements. Many public hops are available to the growers without any additional costs, but their aroma is difficult to match to the proprietary hops. Although proprietary and public hop varieties are unique in their aroma profiles, all hops varieties contain similar volatile compounds, merely differ in the quantity of different individual compounds. The main objective of this thesis was to investigate the feasibility of matching …

Higher Sound Levels In K-12 Classrooms Correlate To Lower Math Achievement Scores, Laura Caroline Brill, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

Sound levels from occupied classrooms have been gathered from 220 classrooms across four grade levels (3, 5, 8 and 11) over six school days each and processed with k-means clustering into speech and non-speech clusters. Three metrics describing the classroom acoustics, including the average daily A-weighted equivalent level for non-speech, the average daily difference between the A-weighted equivalent levels for speech and nonspeech (a signal to noise ratio), and the mid-frequency averaged reverberation time, were analyzed against classroom-aggregated standardized reading and math achievement test scores, while controlling for classroom demographics including socioeconomic status. Interactions between the metrics and demographics were …

The Effects Of The Visual Environment On K-12 Student Achievement, Michael Kuhlenengel, Iason Konstantzos, Clarence E. Waters

Durham School of Architectural Engineering and Construction: Faculty Publications

The varying indoor environments among educational buildings can have an impact on students’ ability to learn. This study looks at field data from 220 classrooms in the Midwest, United States, over a two-year period, to analyze the effects of the visual environment on student achievement. The visual environmental metrics considered within this scope include the three new view metrics introduced within the EN 17037 “Daylight of Buildings” standard (Horizontal Sight Angle, Outside Distance of View, and Number of View Layers), as well as standard daylight and electric lighting metrics, focusing on light availability and glare. To capture student achievement, math …

Simulation For A Mems-Based Ctrnn Ultra-Low Power Implementation Of Human Activity Recognition, Muhammad Emad-Ud-Din, Mohammad H. Hasan, Roozbeh Jafari, Siavash Pourkamali, Fadi M. Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents an energy-efficient classification framework that performs human activity recognition (HAR). Typically, HAR classification tasks require a computational platform that includes a processor and memory along with sensors and their interfaces, all of which consume significant power. The presented framework employs microelectromechanical systems (MEMS) based Continuous Time Recurrent Neural Network (CTRNN) to performHAR tasks very efficiently. In a real physical implementation, we show that the MEMS-CTRNN nodes can perform computing while consuming power on a nano-watts scale compared to the micro-watts state-of-the-art hardware. We also confirm that this huge power reduction doesn’t come at the expense of reduced …

Framework To Develop Time- And Voltage-Dependent Building Load Profiles Using Polynomial Load Models, Andrew Parker, Mhd Anas Alkrch, Kevin James, Ahmad Almaghrebi, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

The power consumption of buildings over the course of each minute, hour, day and season plays a major role in how this load influences the Electric Power System voltage and frequency, and vice versa. This consumption is based on the building's load component types, efficiencies, and how they consume power and react to changes in real time. Due to this complexity, standard full-building load models are typically voltage-invariant. This paper proposes a novel framework to transform these voltage-invariant building load models into fully time- and voltage-dependent load profiles using available data on the voltage sensitivity of individual load components. While …

A Case Study To Quantify Variability In Building Load Profiles, Andrew Parker, Sam Moayedi, Kevin James, Dongming Peng, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

Recent technology development and penetration of advanced metering infrastructure (AMI), advanced building control systems, and the internet-of-things (IoT) in the built environment are providing detailed information on building operation, performance, and user's comfort and behavior. Building owners can obtain a wide range of energy consumption details at various levels of time granularity to augment their decisions as they manage the building operation and interact with the grid. AMI data are providing a new level of detail and visibility that may enhance building services and assets in the smart grid domain and make buildings inch closer to becoming a grid-interactive energy …

Evaluating Prediction Models Of Creep And Drying Shrinkage Of Self-Consolidating Concrete Containing Supplementary Cementitious Materials/Fillers, Micheal Asaad, George Morcous

Durham School of Architectural Engineering and Construction: Faculty Publications

Supplementary cementitious materials (SCMs) and fillers play an important role in enhancing the mechanical properties and durability of concrete. SCMs and fillers are commonly used in self-consolidating concrete (SCC) mixtures to also enhance their rheological properties. However, these additives could have significant effects on the viscoelastic properties of concrete. Existing models for predicting creep and drying shrinkage of concrete do not consider the effect of SCM/filler on the predicted values. This study evaluates existing creep and drying shrinkage models, including AASHTO LRFD, ACI209, CEB-FIP MC90-99, B3, and GL2000, for SCC mixtures with different SCMs/fillers. Forty SCC mixtures were proportioned for …

The Facility Infection Risk Estimator™: A Web Application Tool For Comparing Indoor Risk Mitigation Strategies By Estimating Airborne Transmission Risk, Marcel Harmon, Josephine Lau

Durham School of Architectural Engineering and Construction: Faculty Publications

The COVID-19 pandemic created needs for (a) estimating the existing airborne risk of infection from SARS-CoV-2 in existing facilities and new designs and (b) estimating and comparing the impacts of engineering and behavioural strategies for contextually reducing that risk. This paper presents the development of a web application to meet these needs, the Facility Infection Risk Estimator™, and its underlying Wells–Riley based model. The model specifically estimates (a) the removal efficiencies of various settling, ventilation, filtration and virus inactivation strategies and (b) the associated probability of infection, given the room physical parameters and number of individuals infected present with either …

Designing Gfrp-Reinforced Tilt-Up Wall Panels, Fray F. Pozo-Lora, Marc Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

Tilt-up construction was effectively enabled on a wide scale in 1979, when the ACI committee 551 report on Tilt-up construction was published, the Recommended Tilt-Up Wall Design, aka, the Yellow Book and the subsequent ACI-SEASC Task, aka the Green Book, and another Tilt-up design and construction manual developed by the ACI in 1988. The Tilt-up Concrete Association was created in 1986 by a group of industry professionals who had the need of an organization dedicated to the industry. ACI 551 maintains a document outlining the standard practice for contemporary Tilt-up design and construction. The ACI 551 document does not consider …

Performance Evaluation Of A Prestressed Belitic Calcium Sulfoaluminate Cement (Bcsa) Concrete Bridge Girder, Nick Markosian, Raed Tawadrous, Mohammad Mastali, Robert J. Thomas, Marc Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

Belitic calcium sulfoaluminate (BCSA) cement is a sustainable alternative to Portland cement that offers rapid setting characteristics that could accelerate throughput in precast concrete operations. BCSA cements have lower carbon footprint, embodied energy, and natural resource consumption than Portland cement. However, these benefits are not often utilized in structural members due to lack of specifications and perceived logistical challenges. This paper evaluates the performance of a full-scale precast, prestressed voided deck slab bridge girder made with BCSA cement concrete. The rapid-set properties of BCSA cement allowed the initial concrete compressive strength to reach the required 4300 psi release strength at …

Discrete Rigid Block Analysis To Assess Settlement Induced Damage In Unreinforced Masonry Façades, Ryan Ehresman, Nathan Taylor, Bora Pulatsu, Ece Erdogmus

Durham School of Architectural Engineering and Construction: Faculty Publications

In this study, a system of discontinuous rigid blocks is employed to simulate the possible damage mechanisms in unreinforced masonry (URM) façades and load-bearing frame systems subjected to settlement using the discrete element method (DEM). First, the employed modeling strategy is validated utilizing the available experimental results presented in the literature. Once there is a good agreement between the computational models and experimental findings, a sensitivity analysis is performed to quantify the influence of the input parameters defined in the DEM-based numerical model. Finally, the proposed modeling strategy is further utilized to assess the damage pattern that may develop in …

A Comparison Between Ultrasonic Guidedwave Leakage And Half-Cell Potential Methods In Detection Of Corrosion In Reinforced Concrete Decks, Ahmad Shoaib Amiri, Ece Erdogmus, Dana Richter-Egger

Durham School of Architectural Engineering and Construction: Faculty Publications

This article presents the advantages and limitations of a recently developed Ultrasonic Guided Wave Leakage (UGWL) method in comparison to the well-known Half-Cell Potential (HCP) method in their ability to detect corrosion in reinforced concrete (RC) bridge decks. This research also establishes a correlation between UGWL data and chloride content in concrete RC slabs. Concrete slabs submerged in a 10% NaCl solution were monitored using both methods over a period of six months. The chloride content from the three cores (0.84, 0.55, and 0.18%) extracted from the slab after the 6-month long process all exceeded the chloride threshold values suggested …

The Importance Of Managerial Positions In The Agile Development Process, Adam Gray

Honors Program: Senior Projects (Public)

In software engineering, the Agile development process is becoming one of the most effective methods to handle the issues of continuous change and fast development. However, there are still some perceived issues that many Agile developers face, and a lot of these issues can seemingly stem from their managers. For example, it may seem like the manager is not always up-to-date on the various aspects of the project, or that they have closed off their mind to new ideas. In this paper, we include an in-depth analysis of the various managerial positions that can be found in the Agile development …

Exploiting Pull-In/Pull-Out Hysteresis In Electrostatic Mems Sensor Networks To Realize A Novel Sensing Continuous-Time Recurrent Neural Network, Mohammad H. Hasan, Amin Abbasalipour, Hamed Nikfarjam, Siavash Pourkamali, Muhammad Emad-Un-Din, Roozbeh Jafari, Fadi Alsaleem

Durham School of Architectural Engineering and Construction: Faculty Publications

The goal of this paper is to provide a novel computing approach that can be used to reduce the power consumption, size, and cost of wearable electronics. To achieve this goal, the use of microelectromechanical systems (MEMS) sensors for simultaneous sensing and computing is introduced. Specifically, by enabling sensing and computing locally at the MEMS sensor node and utilizing the usually unwanted pull in/out hysteresis, we may eliminate the need for cloud computing and reduce the use of analog-to-digital converters, sampling circuits, and digital processors. As a proof of concept, we show that a simulation model of a network of …

Quasi-Static Nonlinear Seismic Assessment Of A Fourth Century A.D. Roman Aqueduct In Istanbul, Turkey, Semih Gonen, Ece Erdogmus, Engin Karaesmen, Erhan Karaesmen

Durham School of Architectural Engineering and Construction: Faculty Publications

The majority of architectural heritage consists of load-bearing masonry components made up of stone units and relatively weak mortar joints, yielding potential weak planes for masonry structures where tension and shear failures are expected to occur. Advanced nonlinear analyses are required to simulate these phenomena and predict the corresponding nonlinear structural behavior of historic masonry constructions. In this context, this paper presents a model of a stone masonry Roman aqueduct (the Valens Aqueduct), constructed in the fourth century A.D. in Istanbul, Turkey, to explore the seismic capacity and behavior using the discrete element method (DEM). The employed modeling approach comprises …

Feasibility Of Lora For Smart Home Indoor Localization, Kyungki Kim, Sining Li, Milad Heydariaan, Nour Smaoui, Omprakash Gnawali, Wonho Suh, Min Jae Suh, Jung In Kim

Durham School of Architectural Engineering and Construction: Faculty Publications

With the advancement of low-power and low-cost wireless technologies in the past few years, the Internet of Things (IoT) has been growing rapidly in numerous areas of Industry 4.0 and smart homes. With the development of many applications for the IoT, indoor localization, i.e., the capability to determine the physical location of people or devices, has become an important component of smart homes. Various wireless technologies have been used for indoor localization includingWiFi, ultra-wideband (UWB), Bluetooth low energy (BLE), radio-frequency identification (RFID), and LoRa. The ability of low-cost long range (LoRa) radios for low-power and long-range communication has made this …

Forecasting The Construction Expenditure Cash Flow For Transportation Design-Build Projects With A Case-Based Reasoning Model, Yunping Liang, Baabak Ashuri, Mingshu Li

Durham School of Architectural Engineering and Construction: Faculty Publications

Accurately forecasting the construction expenditure cash flow of transportation projects is critical for state departments of transportation (state DOTs) to secure sufficient funding to cover their fiscal obligations throughout the project development timeline. However, there is no quantitative model to assist state DOTs in accurately forecasting expenditure cash flows for design-build projects. At the outset of awarding a typical design-build contract, the design has not been finalized to enable exact quantities for a detailed cost estimate. This issue represents a big difference between design-build and design-bid-build projects that makes estimating the project payouts more difficult for design-build projects. This research …

Enhancing Bim Implementation In The Ethiopian Public Construction Sector: An Empirical Study, Solomon Belay, James D. Goedert, Asregedew Woldesenbet, Saeed Rokooei3

Durham School of Architectural Engineering and Construction: Faculty Publications

Recently, the popularity of BIM has grown rapidly in the public construction sector. However, only a few studies so far have been seeking to address the BIM adoption benefits and barriers in developmental public projects across the low-income countries. Thus, the study aims to investigate the benefits and barriers of BIM adoption in the context of the Ethiopian infrastructure market. To achieve the objectives, a comprehensive systematic literature review was conducted to identify BIM adoption benefits and barriers in developing countries. Then, a structured questionnaire survey was conducted to collect data from various professionals working in organizations including client, consultant, …

Condition Rating Prediction Using An Interactive Deterioration Model Development Package, Minwoo Chang, Mitchell S. Maguire

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper presents an advanced method to determine explanatory variables required for developing deterioration models without the interference of human bias. Although a stationary set of explanatory variables is ideal for long-term monitoring and asset management, the penalty regression results vary annually due to the innate bias in the inspection data. In this study, weighting factors were introduced to consider the inspection data collected for several years, and the most stationary set was identified. To manage the substantial amount of inspection data effectively, we proposed a software package referred to as the Deterioration Model Development Package (DMDP). The objective of …

Framework For Extracting And Characterizing Load Profile Variability Based On A Comparative Study Of Different Wavelet Functions, Andrew Parker, Kevin James, Dongming Peng, Mahmoud Alahmad

Durham School of Architectural Engineering and Construction: Faculty Publications

The penetration of distributed energy resources (DERs) on the electric power system is changing traditional power flow and analysis studies. DERs may cause the systems' protection and control equipment to operate outside their intended parameters, due to DERs' variability and dispatchability. As this penetration grows, hosting capacity studies as well as protection and control impact mitigation become critical components to advance this penetration. In order to conduct such studies accurately, the electric power system's distribution components should be modeled correctly, and will require realistic time series loads at varying temporal and spatial conditions. The load component consists of the built …

Bayes’ Network And Smart Sensors: Occupancy Detection, Donald Tryon

Department of Construction Engineering and Management: Dissertations, Theses, and Student Research

This dissertation presents a Bayesian analysis for determining residential occupancy using inexpensive commercially available passive infrared (PIR) motion detectors, compared against two other detectors that were used to establish ground-truth. One of the ground-truth detectors was a GPS signal from a smartphone, the second was a Bluetooth key fob. Data were gathered from four residential locations, and then analyzed to determine occupancy. The occupancy data collected from the PIR sensors were compared against ground-truth to verify the results of the PIR sensor events that were collected every minute for a week. The Bayesian training data that was used to determine …

An Iot Framework For Modeling And Controlling Thermal Comfort In Buildings, Fadi Alsaleem, Mehari K. Tesfay, Mostafa Rafaie, Kevin Sinkar, Dhaman Besarla, Parthiban Arunasalam

Durham School of Architectural Engineering and Construction: Faculty Publications

Humans spend more than 90% of their day in buildings, where their health and productivity are demonstrably linked to thermal comfort. Building thermal comfort systems account for the largest share of U.S energy consumption. Despite this high-energy cost, due to building design complexity and the variety of building occupant needs, addressing thermal comfort in buildings remains a difficult problem. To overcome this challenge, this paper presents an Internet of Things (IoT) approach to efficiently model and control comfort in buildings. In the model phase, a method to access and exploit wearable device data to build a personal thermal comfort model …

Ten Questions Concerning Well-Being In The Built Environment, Sergio Altomonte, Joseph Allen, Philomena M. Bluyssen, Gail Brager, Lisa Heschong, Angela Loder, Stefano Schiavon, Jennifer A. Veitch, Lily M. Wang, Pawel Wargocki

Durham School of Architectural Engineering and Construction: Faculty Publications

Well-being in the built environment is a topic that features frequently in building standards and certification schemes, in scholarly articles and in the general press. However, despite this surge in attention, there are still many questions on how to effectively design, measure, and nurture well-being in the built environment. Bringing together experts from academia and the building industry, this paper aims to demonstrate that the promotion of well-being requires a departure from conventional agendas. The ten questions and answers have been arranged to offer a range of perspectives on the principles and strategies that can better sustain the consideration of …

Investigating Multidimensional Characteristics Of Noise Signals With Tones From Building Mechanical Systems And Their Effects On Annoyance, Joonhee Lee, Lily M. Wang

Durham School of Architectural Engineering and Construction: Faculty Publications

This paper investigates multidimensional characteristics of tonal noise from heating, ventilation, and air-conditioning systems, besides loudness and tonality, to improve prediction of annoyance. Two studies were conducted: multidimensional scaling (MDS) analysis to determine what other perceptual signal characteristics are important and perceptual weight analysis (PWA) to understand the impact of multiple tones in a signal. In the MDS study, paired comparison tasks were conducted to gather similarity and annoyance data. Results show that the latent perceptual dimensions are related to the signal’s tonality, loudness, sharpness, and roughness. Including metrics for these perceptions, except roughness, improves the performance of earlier annoyance …

A Novel Structural Health Monitoring Method For Reinforced Concrete Bridge Decks Using Ultrasonic Guided Waves, Ece Erdogmus, Eric Garcia, Ahmad Shoaib Amiri, Michael Schuller

Durham School of Architectural Engineering and Construction: Faculty Publications

This article presents the latest improvements in a recently developed nondestructive testing (NDT) approach for early detection of various flaws (corrosion, delamination, and concrete cracking) in reinforced concrete (RC) bridge decks. The proposed method involves the use of internal steel reinforcement as a wave guide for transmitting ultrasonic waves through the system and the measurement of leaked energy from the surface of the concrete. This paper builds upon the progress made in the previously published phases of the project and aims to further explore the capabilities and practicality of the proposed NDT method. Specifically, the limits of propagation distance, effect …

Analysis Of The Variability Of Project Cost And Schedule Performance In The Design-Build Environment, Yunping Liang, Baabak Ashuri, Wei Sun

Durham School of Architectural Engineering and Construction: Faculty Publications

Design-build (DB) projects are getting more implementations in the United States. Several studies indicate that the DB project delivery system has advantages in project cost and schedule performance. Despite having comparative advantages, DB projects are found to be far from immune from cost overruns and schedule delay in those studies. It is critical to understand the effects of various factors underpinning the cost and schedule performance of DB projects. The overall objective of this research is to utilize cluster analysis and statistical analysis to identify factors with significant potentials to describe the variability of project cost and schedule performance in …