Engineering Commons^™

Meta-Analysis Of Insulated Concrete Wall Panel Design Methods For Shear And Flexure Behavior, Maryam Al-Bayati

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

Insulated Concrete wall panels have been designed and constructed since the early 1950s with various shear ties, dimensions, and methods; nonetheless, thermal bridging and rational design are still a concern. Many companies have recently developed plastic connectors that have gradually replaced solid concrete sections and steel connectors due to their superior thermal efficiency and strength. However, there is no generally accepted method for predicting the behavior of sandwich wall panels in structural engineering practice or codes, but many methods have been used since the early 1920. This study aims to evaluate the accuracy of current methods for predicting the flexural …

Development Of Reduced Cementitious Materials Concrete (Rcmc) Mixtures For Bridge Decks And Rails, Soumitra Das

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

Right after construction, drying shrinkage of restrained concrete bridge decks and rails causes early-age cracking that eventually leads to delamination and spalling of concrete due to insertion of water and chemicals, and corrosion of reinforcing steel. The main objective of this research is to control early-age shrinkage cracking by reducing cementitious material content in the bridge deck and rail concrete mixtures. Several reduced cementitious materials concrete (RCMC) mixtures were developed by optimizing aggregate particle packing and conducting overall performance evaluation. This evaluation was carried out in three phases: The first phase investigated the feasibility of new RCMC mixtures by testing …

Single-Pass Inline Pipeline 3d Reconstruction Using Depth Camera Array, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

A novel inline inspection (ILI) approach using depth cameras array (DCA) is introduced to create high-fidelity, dense 3D pipeline models. A new camera calibration method is introduced to register the color and the depth information of the cameras into a unified pipe model. By incorporating the calibration outcomes into a robust camera motion estimation approach, dense and complete 3D pipe surface reconstruction is achieved by using only the inline image data collected by a self-powered ILI rover in a single pass through a straight pipeline. The outcomes of the laboratory experiments demonstrate one-millimeter geometrical accuracy and 0.1-pixel photometric accuracy. …

Repair And Strengthening Of Concrete Bridges Using Ultra-High-Performance Concrete (Uhpc), Antony Kodsy

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

Reinforced/Prestressed concrete bridges are subjected to environmental effects that cause premature deterioration and require structural repair and strengthening during their service life. Currently 42% of bridges in the United States are at least 50 years old, and 7.5% of them are structurally deficient and need to be repaired/strengthened. Recently, new repair and strengthening techniques using Ultra-High-Performance concrete (UHPC) have shown a great potential with respect to performance, economy, and speed. UHPC is a new class of concrete that has mechanical and durability properties that are far superior to those of conventional concrete (CC). In addition, UHPC offers several advantages compared …

Using Cost Simulation And Computer Vision To Inform Probabilistic Cost Estimates, Shu Jing Ding

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

Cost estimating is a critical task in the construction process. Building cost estimates using historical data from previously performed projects have long been recognized as one of the better methods to generate precise construction bids. However, the cost and productivity data are typically gathered at the summary level for cost-control purposes. The possible ranges of production rates and costs associated with the construction activities lack accuracy and comprehensiveness. In turn, the robustness of cost estimates is minimal. Thus, this study proposes exploring a range of cost and productivity data to better inform potential outcomes of cost estimates by using probabilistic …

Reducing Early-Age Shrinkage Cracks Of Bridge Decks And Rails, Soumitra Das, George Morcous, Jiong Hu

UNL Student Research Days Posters, Graduate

Early-age shrinkage cracking of concrete bridge decks and rails accelerates the penetration of water and chemicals which leads to reinforcement corrosion, delamination, and eventually spalling. All this results in shorter service life, road closure, and costly repair. Development of Low-cement concrete(LCC) mix to reduce early age shrinkage crack through aggregate grading optimization was done in this research work. This approach also reduces concrete cost ($15-$20/cyd) (15–25%) and its carbon footprint (≈15%).

Integration Management: A Bibliometric Study Of Research Trends, Shabir Hussain Khahro, Ayaz Babar, Fida Hussain Siddiqui, Tauha Hussain Ali, Ali Raza Khoso

Library Philosophy and Practice (e-journal)

Integration management has always been a topic of interest for researchers. It plays a significant role in the success of the projects. Integration management effectively incorporates all the aspects of projects and provides a roadmap towards their success. Based on the significance of the term, this paper assesses the research output of integration management since 1970 in different fields of the application using the Scopus database. The data was collected and analyzed through Microsoft Excel to analyze the research publications trend line, publication types and their access to the audience, organizations and countries involved, languages of publications, authors participating, and …

Exploration Of The Sludge Biodiesel Pathway, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wastewater sludge is an overlooked source of fat, oil, and grease (FOG) that could be converted into biodiesel. The United States produces about 8 million tons of sludge per year. The disposal cost for this amount of sludge is about 2 billion dollars. The widespread availability and low cost of sludge compared to other biodiesel raw materials make it an economical choice for a renewable fuel. Using sludge as a raw material can produce 25 to 30 mg per gram of fatty acid methyl ester (FAME); the main component of biodiesel. Sludge biodiesel has the potential of transforming a portion …

Ultra-High Performance Concrete (Uhpc) Deck-To-Girder Connection For Accelerated Bridge Construction, Mostafa Abo El-Khier

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

Precast concrete deck systems have been successfully used for Accelerated Bridge Construction. In most systems, special deck-to-girder connections are designed to achieve structurally composite sections. These connections require tight production/erection tolerances that complicate deck and girder fabrication and compromise the economics of these systems. This study presents a new precast concrete deck-to-girder connection that takes advantage of the excellent mechanical, workability, and durability properties of ultra-high performance concrete (UHPC) to simplify precast concrete deck and girder fabrication and erection. Typical girder shear reinforcement is terminated below the soffit of deck panels to eliminate any conflicts with deck reinforcement and relax …

Facilitating The Industrial Sector's Adoption Of Collaborative Project Delivery Methods, Xavier Wood-Aliberch

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

In an effort to improve outcomes in the civil and healthcare sectors, clients have adopted collaborative project delivery methods for the delivery of their capital projects. The success stories in these sectors have gathered the attention of clients in the industrial sector, where cost and schedule overruns have become the norm. The central objective of this thesis is to help clients make the transition to this new type of project delivery.

This thesis was written in a three-paper format, where each paper addresses a challenge with the adoption of collaborative delivery methods. The first paper investigates what type of industrial …

Advanced Concrete Composites For Improved Performance: A Bibliometric Survey, Dhruv Patel, Aryan Tiwari, Nishnat Nikhare, Rohit Shinde, Ashutosh Dubey, Manan Shah, Shalaka Hire, Sayali Sandbhor

Library Philosophy and Practice (e-journal)

Concrete is the core component of any civil engineering construction. Conventional concrete can be modified depending upon the needs and requirements of the construction. Such concrete is called advanced concrete and this report aims to study advanced concrete and its composites. The main objective of this report is to perform a bibliographic survey on the latest research literature available under the domain of advanced concrete composites for improved performance. Timespan considered for the survey is from the year 2015 to 2020. The bibliographic survey consists of literature from online platforms such as the Web of Science (WoS) and Scopus database. …

Applications Of Biomimicry In Construction And Architecture: A Bibliometric Analysis, Mugdha Praveen Kshirsagar Mrs, Sanjay Kantrao Kulkarni Dr, Ankush Kumar Meena Mr, Danby Caetano D’Costa Mr, Sushant Sunil Bhavsar Mr

Library Philosophy and Practice (e-journal)

Biomimicry can be considered to be a way of connecting the environment created by man to the natural world. Biomimicry is a science that, as a model, a measure and a tutor, looks to nature. Via site work, construction and everyday operations, biomimicry can be used to enhance the way the built environment is constructed. The main objective of this paper is to perform a bibliometric study of biomimicry-related literature in order to discover the growth of biomimicry as an architectural method in recent years. The time frame considered for this survey is between 1990 and 2020. The findings, however, …

A Bibliometric Analysis Of Global Research On Green Building Rating Tools., Janhavi Kailas Mahale Ms, Kanchan C. Khare Dr

Library Philosophy and Practice (e-journal)

The movement of green buildings started all over the world after the development of different rating tools for the assessment of green buildings. In the present study, the research trends in the area of green building rating tools (GBRTs) were analysed through the Scopus database from the year 2000-2020. By using the different combinations of keywords, relevant articles were found after refining the search results. In this study, 482 relevant articles from the first set of keywords were considered till the period 4^th February 2021 for further analysis. Results reveal that research on GBRTs was majority done only on …

An Assessment Of Research Trends On Fiscal Policy, Shabir Hussain Khahro, Shoail Farooq, Tauha Hussain Ali Dr, Nafees Ahmed Memon Dr, Qasim Hussain Khahro

Library Philosophy and Practice (e-journal)

Fiscal policy has been a topic of research interest for researchers. It plays a very important role in the economic growth of any country. Fiscal policy does not only achieve economic development, but eliminates the hindrances that assist economic stability. Based on the significance of the term. This paper evaluates the research output of the term fiscal policy since 1970 in different fields using the Scopus database. The data was collected from the Scopus database and were analyzed using Microsoft Excel to analyze the research trends on fiscal policy. It is concluded that fiscal policy has been a topic of …

Quality Control In Concrete Pavement: Early Detection Of Near-Surface Honeycombing With Gpr, Theresa Mccabe

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

This thesis presents utilization of Ground Penetrating Radar (GPR) for the assessment of highway pavements to gain a better understanding of this NDE method’s capabilities in terms of early detection of consolidation-caused air voids in brittle materials. The objectives are to first, determine the earliest time during the dormant, setting, and early hardening periods of concrete’s set that GPR can be used to detect shallow air voids. Secondly, the change in dielectric constant will be tracked over the first 24 hours of concrete setting in order to quantify the impact of the dielectric constant assumptions in early detection. Two different …

Semi Real-Time Detection Of Subsurface Consolidation Defects During Concrete Curing Stage, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Subsurface consolidation defect is a common issue in concrete pavement construction, and the hidden defects often require costly repairs after project delivery. Therefore, being able to identify this type of defect during construction will enable contractor to conduct quick repairs to avoid costly post-construction rework. In this paper a semi real-time detection approach using infrared thermography is introduced. The developed approach utilizes the hydration heat during curing time to identify the subsurface voids based on the regional temperature contrast. Experimental studies were conducted using artificial void-defect in different sizes and depths. The thermographic analysis is employed to locate the void-defects …

Automatic Delamination Segmentation For Bridge Deck Based On Encoder-Decoder Deep Learning Through Uav-Based Thermography, Chongsheng, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Concrete deck delamination often demonstrates strong variations in size, shape, and temperature distribution under the influences of outdoor weather conditions. The strong variations create challenges for pure analytical solutions in infrared image segmentation of delaminated areas. The recently developed supervised deep learning approach demonstrated the potentials in achieving automatic segmentation of RGB images. However, its effectiveness in segmenting thermal images remains under-explored. The main challenge lies in the development of specific models and the generation of a large range of labeled infrared images for training. To address this challenge, a customized deep learning model based on encoder-decoder architecture is proposed …

Evaluation Of The Dynamic Behavior Of Steel Staircases With Concrete Filled Pan Treads, Tyler Sondag

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

Vibration serviceability of staircases has been a growing challenge for structural engineers due to changing materials and structural forms. In order to prevent or correct serviceability problems due to structural vibrations, structural engineers should be able to predict the dynamic performance of a staircase structure. However, there are few technical guides available for designing steel staircases, and the ones that do exist are often limited in their applications. Currently, there is a lack of research on staircases that are less prone to vibrations, such as staircases with concrete filled pans that are composed of face and wall stringers. Therefore, the …

Construction Labor Productivity Modeling And Use Of Neural Networks: A Bibliometric Survey, Shalaka Hire, Sayali Sandbhor

Library Philosophy and Practice (e-journal)

Productivity of a project has a major impact on its cost and profitability. In spite of construction being labor intensive field with labor cost adding up to 30% to 50% of overall project cost, the productivity of labor is one of the least studied areas in the construction industry. It requires to be given due attention to the issues affecting labor productivity and design solution using soft computing techniques to improve the overall performance of the industry. This research paper aims to conduct a bibliographic survey of the literature available in the domain of Labor Productivity (LP) as well as …

Evaluation Of An Interview-Based Internship Class In The Construction Management Curriculum: A Case Study Of The University Of Nebraska-Lincoln, Ali Karji, Stuart Bernstein, Mohammadsoroush Tafazzoli, Arash Arash Taghinezhad, Arefeh Mohammadi

Department of Construction Engineering and Management: Faculty Publications

Internships have been shown to be impactful tools to connect students’ learning in academia with real-world industrial needs. To help the students to get more out of their internship experience, some universities provide a summer internship class in which students do class assignments based on their experiences during their internship. There have been numerous studies on the benefits of internships. However, the benefits of a potential internship class for students in construction management (CM) programs at universities have not yet been investigated. This paper demonstrates the structure of an interview-based internship class and investigates its effectiveness. We have focused on …

The Application Of Gray-Scale Level-Set Method In Segmentation Of Concrete Deck Delamination Using Infrared Images, Chongsheng Cheng, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Conventional nondestructive delamination detection of concrete pavements through thermography is often based on temperature contrasts between delaminated and sound areas. Non-uniform backgrounds caused by the environmental conditions are often challenging for contrast-based methods to robustly differentiate the delaminated areas from the sound areas. Instead of focusing on the temperature contrast, this study proposes a temperature gradient-based level set method (LSM) to detect boundaries for delamination segmentations. A modified edge indicator function is developed to represent the normalized temperature gradient of a thermal image. The experimental study was conducted to evaluate its applicability and stability for boundary detection in terms of …

A Co-Optimal Coverage Path Planning Method For Aerial Scanning Of Complex Structures, Zhexiong Shang, Justin Bradley, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

The utilization of unmanned aerial vehicles (UAVs) in survey and inspection of civil infrastructure has been growing rapidly. However, computationally efficient solvers that find optimal flight paths while ensuring high-quality data acquisition of the complete 3D structure remains a difficult problem. Existing solvers typically prioritize efficient flight paths, or coverage, or reducing computational complexity of the algorithm – but these objectives are not co-optimized holistically. In this work we introduce a co-optimal coverage path planning (CCPP) method that simultaneously co-optimizes the UAV path, the quality of the captured images, and reducing computational complexity of the solver all while adhering to …

Bridge Deck Delamination Segmentation Based On Aerial Thermography Through Regularized Grayscale Morphological Reconstruction And Gradient Statistics, Chongsheng Cheng, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Environmental and surface texture-induced temperature variation across the bridge deck is a major source of errors in delamination detection through thermography. This type of external noise poises a significant challenge for conventional quantitative methods such as global thresholding and k-means clustering. An iterative top-down approach is proposed for delamination segmentation based on grayscale morphological reconstruction. A weight-decay function was used to regularize the reconstruction for regional maxima extraction. The mean and coefficient of variation of temperature gradient estimated from delamination boundaries were used for discrimination. The proposed approach was tested on a lab experiment and an in-service bridge deck. The …

Thermographic Laplacian-Pyramid Filtering To Enhance Delamination Detection In Concrete Structure, Chongsheng Cheng, Ri Na, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Despite decades of efforts using thermography to detect delamination in concrete decks, challenges still exist in removing environmental noise from thermal images. The performance of conventional temperature-contrast approaches can be significantly limited by environment-induced non-uniform temperature distribution across imaging spaces. Time-series based methodologies were found robust to spatial temperature non-uniformity but requires extended period to collect data. A new empirical image filtering method is introduced in this paper to enhance the delamination detection using blob detection method that originated from computer vison. The proposed method employs a Laplacian of Gaussian filter to achieve multi-scale detection of abnormal thermal patterns by …

The Impact Of Extreme Virtual Elevation Above Grade On Construction Workers' Physiological Responses, Physical Responses, And Task Performance, Mahmoud Habibnezhad

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

On average, in every two work hours, one person dies from work-related injuries at construction sites. Most incidents are due to falling from elevated surfaces. Slips, trips, and loss of balance are the main causes. Studies suggest that instigating visual mismatch and physiological changes are among the most important reasons behind falling from narrow elevated surfaces. By using advanced virtual reality models, this dissertation aims to highlight some of the possible effects of a destabilizing environment (i.e., elevation above grade) on workers’ physiological responses and task performance. More specifically, this dissertation strives to find potential effects of elevation above grade …

Assessing Impact And Blast Resilience Of Polymer Coated Cementitious Materials, Murtaza Nalwala, Gabriel Nsengiyumva, Yong-Rak Kim

UCARE Research Products

RESEARCH MOTIVATION The bridge piers are highly vulnerable to the impact and blast loads. The position in which they are constructed makes it difficult to install protective devices around them. By the current AASHTO standard, it is possible to under-design bridge piers for commercial vehicle impacts and other events such as blast.

OBJECTIVE To improve impact and blast resilience of bridge piers using polymeric coatings.

CONCLUSION Polymer coating of Portland cement concrete can be achieved with a good bonding. ü The polymeric coating seem to improve impact resilience of Portland cement concrete by increasing absorbed impact energy (i.e., area underneath …

Evaluation And Development Of Cpt Based Pile Design In Nebraska Soils, Alex Silvey

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Cone penetration testing (CPT) is a well established geotechnical subsurface investigation technique commonly used for site characterization and soil classification. The CPT gives real time end resistance, side friction, and pore pressure readings. Axially loaded piles also share these two resistance mechanisms, suggesting the cone can be considered similar to a miniature pile. This study focused on evaluating eight CPT methods prediction of pile bearing capacity. The Nebraska Department of Roads (NDOR) conducts dynamic load tests (PDA) of driven pile to verify pile capacity for bridge foundations. 91 comparisons of CPT logs and PDA data were evaluated. CPT prediction methods …

A Study On Residential Construction Energy Code Compliance In Nebraska, Aaron Thompson

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

Energy codes are easy to implement, but how effectively are they being followed? To determine energy code compliance of residential construction in Nebraska, a study was conducted in which seven key areas having the most effect on energy savings were analyzed. The study examined both urban and rural areas of the state and compared Nebraska to other states’ energy code compliance studies. The study found an eighty-eight percent average compliance in the key areas. Urban areas tended to be more compliant than rural areas. Nebraska is comparative in energy code compliance to other states. Yet, the state of Nebraska, code …

Multi-Point Vibration Measurement And Mode Magnification Of Civil Structures Using Video-Based Motion Processing, Zhexiong Shang, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Image-based vibration measurement has gained increased attentions in civil and construction communities. A recent video-based motion magnification method was developed to measure and visualize small structure motions. This new approach presents a potential for low-cost vibration measurement and mode shape identification. Pilot studies using this approach on simple rigid body structures were reported. Its validity on complex outdoor structures has not been investigated. In this study, a non-contact video-based approach for multi-point vibration measurement and mode magnification is introduced. The proposed approach can output a full-field vibration map that increases the efficiency of the current structural health monitoring (SHM) practice. …

Effects Of Nitrogen And Phosphorus Fertilizer And Topsoil Amendment On Native Plant Cover In Roadside Revegetation Projects, Heidi L. Hillhouse, Walter H. Schacht, Jonathan M. Soper, Carol E. Wienhold

Department of Agronomy and Horticulture: Faculty Publications

Establishing vegetation on roadsides following construction can be challenging, especially for relatively slow growing native species. Topsoil is generally removed during construction, and the surface soil following construction (“cut-slope soils”) is often compacted and low in nutrients, providing poor growing conditions for vegetation. Nebraska Department of Transportation (NDOT) protocols have historically called for nitrogen (N) and phosphorus (P) fertilization when planting roadside vegetation following construction, but these recommendations were developed for cool-season grass plantings and most current plantings use slower-establishing, native warmseason grasses that may benefit less than expected from current planting protocols. We evaluated the effects of nitrogen and …