Engineering Commons^™

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. …

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 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 …

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. …

Simulation As Supplementary Tool In Construction Management Education, Saeed Rokooei, James D. Goedert, Asregedew Woldesenbet

Department of Construction Engineering and Management: Faculty Publications

Many academic programs utilize simulation applications to supplement higher education, but there are only a few applications responding to the need in construction curricula, particularly with a focus on project management. Project management is an interdisciplinary area of study, crosscutting multiple fields including the construction, information technology, and business sectors. This paper presents the design, development, and test of a research project entitled Project-oriented Educational Research Fostering Excellence in Cyber-infrastructure Teaching (PERFECT). It investigates the effect of a construction project management simulation on construction management students’ engagement and perceptions at the University of Nebraska- Lincoln.

The goal of PERFECT was …

Investigating Students’ Perception Using Construction Management Simulations, Saeed Rokooei, James D. Goedert, Asregedew Woldesenbet

Department of Construction Engineering and Management: Faculty Publications

Today, construction programs are incorporating a wide variety of active learning methods in their curricula to improve student learning outcomes and induce a more knowledge retention rate. Simulations and educational games are one of the fast growing and effective active learning methods that have been implemented in many programs. However, there are few instances of such learning methods applied in construction programs and a limited number of research projects have been conducted to investigate short-term and long-term outcomes of these methods and applications. This paper presents construction students’ perceptions of tested simulations with regards to the features, knowledge gained, level …

Lessons Learned From A Simulation Project In Construction Education, Saeed Rokooei, James D. Goedert

Department of Construction Engineering and Management: Faculty Publications

Virtual Interactive Construction Education (VICE) is a simulation designed for construction education. The purpose was to provide the traditional lecture-based construction contents along with supplementary instructions in a project-based learning environment. Six modules were proposed as a curriculum delivery guideline including: single span bridge, residential building, light commercial, heavy commercial, highway, and segmental bridge. The single span bridge was the first module used for prototype development providing an opportunity to design, analyze, implement, and test for effectiveness. This paper describes the design steps and results of this three-year research project. VICE-Bridge required participants to sequentially order the construction activities and …

Using Simulated Virtual Interactivity In Construction Education, Saeed Rokooei, James D. Goedert

Department of Construction Engineering and Management: Faculty Publications

This paper briefly illustrates the design procedure, implementation and findings of a three year research project. Virtual Interactive Construction Education (VICE) is a project-based pedagogical model that uses a simulated environment to alter traditional subject-based lectures into virtual project-based interactive learning methods in construction education. For this purpose, the context of construction engineering and management curricula were aggregated into six construction project prototypes. VICE-Bridge is the first of these six prototypes that exposes players to experiential problem solving activities toward achieving a goal situation (construct the bridge) from an initial situation (start of construction). It was designed for students with …

A Case-Crossover Study Of Laceration Injuries In Pork Processing, Lina Lander, Gary Sorock, Terry L. Stentz, Lynette Smith, Murray Mittleman, Melissa J. Perry

Department of Construction Engineering and Management: Faculty Publications

Objectives— The authors estimated the associations between transient risk factors and laceration injuries in workers at two meatpacking plants in the Midwest.

Methods— The case-crossover design was used to collect within-subject transient work task and personal-level exposure information. RRs of laceration injuries were estimated by comparing exposures during the ‘hazard’ period (just before the laceration injury) with exposures in the ‘control’ period (the previous workweek). Stratified analyses were utilized to estimate the effects of gender, ethnicity, training and the number of adjacent coworkers on each transient risk factor.

Results— The authors interviewed 295 meatpacking workers with laceration injuries (mean age …

A Building Lca Case Study Using Autodesk Ecotect And Bim Model, Endong Wang, Zhigang Shen, Charles Barryman

Department of Construction Engineering and Management: Faculty Publications

The main objective of this study is to evaluate the potential of utilizing building information model (BIM) to perform whole building Life Cycle Analysis (LCA). The research question addressed was how life cycle performance of a building was affected quantitatively by design configurations. Life cycle energy consumption and CO₂ emission of a university building in the Midwest was calculated using Autodesk® Ecotect and BIM model. The study compared life cycle performance, i.e., CO₂ emissions and energy consumptions, among different design configurations, as well as their distributions in the stages of the building’s life time. Sensitivity analysis was performed …

Limited Scope Permitting For Time-Sensitive Project Delivery Systems, Wayne Jensen, Bruce Fischer, Zhigang Shen

Department of Construction Engineering and Management: Faculty Publications

Delivery of construction projects in the United States has traditionally been based upon the design-bid-build system. TIlis system has been used to create numerous impressive structures, but it often proves expensive and usually requires considerable time, because design, permitting and construction are accomplished in sequential order and do not overlap. Several alternatives to the traditional system have been developed, many of which fall under the classification of time-sensitive project delivery systems. The most commonly used time-sensitive project delivery systems are phased and fast-track construction (FaZio, Moselhi, Theberge & Revay 1988a). Figure 1 illustrates some of the major differences between traditional …

The Aerodynamic Behaviour Of Respiratory Aerosols, Kristin K. Grosskopf

Department of Construction Engineering and Management: Faculty Publications

Hospital acquired infections (HAIs) claim on average 90,000 lives each year in the U.S., nearly three times the number of annual highway deaths. Although fewer than 15% of HAIs are directly attributable to airborne transmission, more than a third may be caused by surface microbes aerosolized by the movement of air from building systems, people and equipment. As a result, a study was devised to use a synthetic respiratory aerosol to track the movement airborne contagion with respect to various environmental conditions in a healthcare environment.

Complex Engineering System Learning Through Study Of Engineering Failure Cases Using 3d Animations, Zhigang Shen, Yimin Zhu

Department of Construction Engineering and Management: Faculty Publications

Complex engineering systems often require dynamic coordination of multidisciplinary teams with conflicting objectives. Failing to understand the complex relationships among the conflicting objectives may result in serious engineering failures. In engineering education, one of the challenges in teaching complex systems is the lack of effective tools to demonstrate system dynamics, especially spatial-temporal relationships in the system. The described project in this paper is supported by grants from Engineering Education program of the National Science Foundation. In the project civil/construction engineering cases are used as the context to test the proposed new teaching/learning tool on the subject and to demonstrate the …

Quantitative Evaluation Of The Bim-Assisted Construction Detailed Cost Estimates, Zhigang Shen, Raja R. A. Issa

Department of Construction Engineering and Management: Faculty Publications

The increased interest in using Building Information Modeling (BIM) in detailed construction cost estimates calls for methodologies to evaluate the effectiveness of BIM-Assisted Detailed Estimating (BADE) tools in generating detailed construction cost estimates. The focus of this study is on developing a quantified evaluation method to measure the impact of these BADE tools. Further, in order to understand the cognitive details of the estimator, this study also tested and evaluated the impact of the visualization factor and the compound impact of the visualization factor and aggregated calculation factor on the construction cost-estimating process. Two types of BADE tools were tested …

Measuring Performance Of Innovative Pavement Features, Wayne Jensen, Zhigang Shen, Cody Kluver

Department of Construction Engineering and Management: Faculty Publications

The Nebraska Department of Roads (NDOR) conducts annual examinations of the state's interstate and federal highway pavements. During these examinations, numerous indicators of pavement performance are measured directly or compiled from parameters recorded by a vehicle passing over the pavement section. Parameters are documented and analyzed for each one-tenth mile pavement segment. Seven sections where innovative features have been incorporated into the pavement were selected by the NDOR for comparison to nearby conventional pavement sections. This study used various parameters recorded by the NDOR as well as field observations to compare the performance of seven pairs of pavement sections. Each …

Semantic 3d Cad And Its Applications In Construction Industry — An Outlook Of Construction Data Visualization, Zhigang Shen, Raja R. A. Issa, Linxia Gu

Department of Construction Engineering and Management: Faculty Publications

In response to the need of using electronic design data directly in construction management applications, many CAD developers have started implementing semantic data models in their CAD products using industry foundation classes (IFCs). While helpful, these semantic CAD applications have limitations when used in actual construction practices. The case studies in the thesis indicated that: 1) the semantics of the current data model (IFC as an example) is not rich enough to cover the richer details of the real trade practices; 2) the current implementation of the semantic data model lacks the mechanism to provide multiple trades views at various …

A Trade Construction Knowledge Module To Enable Use Of Design Component Data In Project Management, Zhigang Shen, Raja R. A. Issa, William J. O'Brien, Ian Flood

Department of Construction Engineering and Management: Faculty Publications

The complexity, tight budget, and dynamic market of today's construction project require the seamless integration of both design and construction data, However, despite the availability of both digital design tools (various CAD applications) and digital project management tools (such as schedule software and construction management software), design data has to still be entered manually into construction applications. In order to close this gap, CAD applications widely used in AEC industries are evolving toward providing the product data within the CAD package itself, in addition to the existing graphic-oriented data. While useful, those new data-driven CAD applications are largely design-oriented and …

A Model For Integrating Construction Design And Schedule Data, Zhigang Shen, Raja R. A. Issa, William O'Brien

Department of Construction Engineering and Management: Faculty Publications

The difficulty of timely retrieval of useful information from heterogeneous data sources is a major cause of low productivity in the construction industry. The goal of this research is to provide a new methodology to handle the data-heterogeneity problems encountered in a construction project. This research proposes a tree-structured product model, which binds design knowledge, cost data and schedule data together, as a feasible solution for the data integration problem in construction projects. The methodology uses the knowledge representation of construction projects based on an ontology. Metadata are used to describe the conceptual structure of the project knowledge. The concept …