Fei Dai

West Virginia University | WVU · Department of Civil and Environmental Engineering

Background This study aimed to assess how knee savers (KSs) and knee pads (KPs) alleviate risks of knee musculoskeletal disorders (MSDs) among roofers during various phases of shingle installation. These phases encompass (1) reaching for shingles, (2) placing shingles, (3) grabbing a nail gun, (4) moving to the first nailing position, (5) nailing s...

Construction robots play a pivotal role in enabling intelligent processes within the construction industry. User‐friendly interfaces that facilitate efficient human–robot collaboration are essential for promoting robot adoption. However, most of the existing interfaces do not consider contextual information in the collaborative environment. The sit...

Awkward kneeling in sloped shingle installation operations exposes roofers to knee musculoskeletal disorder (MSD) risks. To address the varying levels of risk associated with different phases of shingle installation, this research investigated utilizing machine learning to automatically classify seven distinct phases in a typical shingle installati...

In construction, the accurate measurements are important in ensuring the quality of work delivered. Different measuring tools have been developed to help workers conduct accurate measuring. However, they may be subject to manipulation difficulties, such as the need for tap/gesture interaction. This paper proposes a novel eye gaze-aided virtual tape...

The labor-intensive nature of the construction industry requires workers to frequently perform physically demanding manual work, thereby exposing them to the risk of musculoskeletal injury (approximately 31.2 cases per 10,000 full-time equivalent workers). Exoskeletons and exosuits (collectively called EXOs here) are designed to protect workers fro...

Exoskeletons and exosuits (collectively termed EXOs) have the potential to reduce the risk of work-related musculoskeletal disorders (WMSDs) by protecting workers from exertion and muscle fatigue due to physically demanding, repetitive, and prolonged work in construction workplaces. However, the use of EXOs in construction is in its infancy, and mu...

Overheight vehicle collisions continuously pose a serious threat to transportation infrastructure and public safety. This study proposed a vision‐based method for automatic vehicle height measurement using deep learning and view geometry. In this method, vehicle instances are first segmented from traffic surveillance video frames by exploiting mask...

The stochastic subspace identification (SSI) method has been recognized as the most dominant and popular system identification technique in the time domain. Nevertheless, it cannot cope with the non-synchronicity of dynamic response measurements that happens sometimes in structural health monitoring practice. To overcome this, this study proposes a...

The construction industry is labor-intensive and physically demanding even with continuous development of advanced tools and machines. Workers are heavily involved in manual procedures, which constantly expose them to a great risk of injury. Recently, exoskeletons and their potential to protect workers from injury have received wide attention. Sign...

Slips and falls on sloped roof surfaces remain an important safety issue among construction workers. The slip potential has been conventionally analyzed and assessed primarily based on ground reaction forces, which cannot differentiate the specific roles of each of the force factors (e.g., workers’ motions-induced dynamic forces and slope-induced s...

A ramp bridge in Hangzhou of Zhejiang Province in China collapsed on April 14, 2017. This paper presented a forensic analysis of the collapse that combines bridge metadata, witness accounts, video footages that captured the event, and numerical simulations. The forensic case study showed that the replacement of the originally symmetric section of t...

Awkward and extreme kneeling postures required during shingle installation on sloped rooftops generates large muscular tension on lower extremities of residential roofers. This study assessed the effects of kneeling posture and roof slope on the peak activations of knee flexor (biceps femoris and semitendinosus) and extensor (rectus femoris, vastus...

Field or laboratory data collected for work-related musculoskeletal disorder (WMSD) risk assessment in construction often becomes unreliable as a large amount of data go missing due to technology-induced errors, instrument failures or sometimes at random. Missing data can adversely affect the assessment conclusions. This study proposes a method tha...

Awkward and extreme kneeling during roofing generates high muscular tension which can lead to knee musculoskeletal disorders (MSDs) among roofers. However, the combined impact of roof slope and kneeling posture on the activation of the knee postural muscles and their association to potential knee MSD risks among roofers have not been studied. The c...

Trunk musculoskeletal disorders are common among residential roofers. Addressing this problem requires a better understanding of the movements required to complete working tasks, such as affixing shingles on a sloped residential roof. We analyzed the extent to which the trunk kinematics during a shingling process are altered due to different angles...

Repeated and prolonged awkward kneeling can result in musculoskeletal disorders (MSD) in construction roofers. However, a task-specific risk assessment for roofers’ knee injuries is still missing in the literature. This study identified a ranking-based ergonomic method for suggesting potentially risky phases that may increase knee MSD risk during s...

One factor commonly associated with musculoskeletal disorder risk is extreme postures. To lessen this risk, individuals must be in an as neutral posture as possible while working. We analyzed how the inclusion of different combinations of two interventions-knee pads and knee savers-can alter lower extremity kinematics during deep or near full flexi...

Aligning workers and groups with workspaces in advance to enable peak performance and ensure safety is the essence of workspace planning. There are plans, while there have been few methods for examining these plans. We argue that capturing and visualizing actual dynamic workspaces is fundamental to plan examination. This paper describes an initial...

Roofers often suffer from musculoskeletal disorders (MSDs) to their knees due to spending a large amount of time kneeling while performing work-related roofing activities on sloped rooftops. Several ergonomic studies have identified kneeling as a potential risk factor for knee injuries and disorders. Existing biomechanical models and sensor technol...

The objective of this study is to identify a ranking method for assessing the potential risk of knee musculoskeletal disorders (MSD) among construction roofers. On a slope-adjustable wooden platform, nine subjects performed the shingle installation, comprising seven phases: 1) reaching for shingles, 2) placing shingles, 3) grasping the nail gun, 4)...

The collapse of the Taihe Bridge—located in the Jiangxi Province of China—on September 11, 2016 during what was intended to be a controlled demolition is forensically investigated here using police reports, analyses of site surveillance videos, and a debris survey. Two sets of numerical simulations were conducted to verify the collapse mechanism es...

As a traditional industry such as the construction, it is hard to collect data for management and improvement. Traditional ways such as questionnaire survey, interviews, or focus meetings to collect data are both time- and cost-consuming. Recently, with the rapid development of social media services, data can be collected and extracted for topic an...

Communication plays a vital role in risk identification and accident prevention in construction workplaces. Current practices that rely on modes such as phone calls and video conferencing do not facilitate instance access to information, context-based perception, and visual interaction that are essential for effective communication in modern constr...

Measuring the value of research results is very important to justify the efficiency and effectiveness of research programs. However, it has received very little attention by transportation agencies and researchers because of the lack of knowledge in benefit measures, scarcity of data required, and absence of consistent quantification methods. The p...

Timely and overall knowing the states and resource allocation of diverse activities on construction sites is critical to resource leveling, progress tracking, and productivity analysis. Despite its importance, this task is still performed manually. Previous studies have taken a significant step forward in introducing computer vision technologies to...

The increasing use of the Internet for many purposes is creating big data, many of which are generated from social media. These big data potentially could assist in obtaining valuable administrative information and even explore new social phenomena. Traditional ways of collecting data, such as questionnaire surveys, are time-consuming and costly. T...

Roofers have long suffered from low back disorders (LBDs), which are a primary nonfatal injury in construction. Ergonomic studies have identified several risk factors associated with LBDs in workplaces and developed biomechanical models for general LBD risk assessments. However, these models cannot be directly used for assessments in roof workplace...

As a sector associated with high injury and fatality rates, the construction industry requires constant caution with regard to construction laborers during project execution. Different from people in other industries, construction workers are less sensitive to hazards because of their long-term exposure to risks. Therefore, maintaining construction...

The overturning limits of single-column pier bridges subject to overloading can be predicted using various approaches ranging in complexity from close-form formulas to detailed finite-element simulations. A simple analytical method - dubbed here analytical overturning limit analysis (AOLA) - is proposed to predict the overturning loads for single-c...

In the roof contracting industry, safety violations continuously lead to fall injuries and fatalities. Occupational Safety and Health Administration (OSHA) suggests standard protective measures, but they are often not followed due to factors such as tight budget and lack of training. To alleviate this situation, we propose to develop a system that...

Quickly changing and complicated workplace conditions, which are typical of construction projects, have always been contributing to the poor safety record of the construction industry. However, few of existing approaches to reviewing control measures take into account or effectively tackle them. This paper introduces a three-level (i.e., individual...

Purpose Roofing is one of the most dangerous jobs in the construction industry. Due to factors such as lack of planning, training and use of precaution, roofing contractors and workers continuously violate the fall protection standards enforced by the US Occupational Safety and Health Administration. A preferable way to alleviate this situation is...

Vision-based tracking for project related entities has attracted practitioners’ interests and attentions; it can provide beneficial data for productivity analysis and safety monitoring. Some studies on tracking workforce and equipment using video cameras placed onsite have proved the feasibility and efficiency of vision-based tracking methods. Howe...

Uneven ground surface is a common occupational injury risk factor in industries such as agriculture, fishing, transportation and construction. Studies have shown that antero-posteriorly slanted ground surfaces could reduce spinal stability and increase the risk of falling. In this study, the influence of antero-posteriorly slanted ground surfaces o...

The effect of anteroposteriorly slanted ground surface on human posture control at fully flexed trunk postures was investigated in this study. Custom made wooden apparatus were used to simulate slanted ground surfaces, the slanted were set at -15, 0 and 15 degrees respectively. The flat ground condition was included in the study as a control. Fourt...

The surveying technique of photogrammetry has been proven to be safe, efficient, and inexpensive to extracting spatial data (i.e. shape, size, position) of infrastructure from collected photos. These data are useful in many infrastructure and construction applications such as quality control and quantity take-off. However, photogrammetry has not be...

The guest editors of this special issue would like to express their sincere gratitude to all the authors and anonymous reviewers who have generously contributed to this special issue.

The capacity that computer can solve more complex design problem is gradually increased. Progressive collapse simulation of masonry arch bridge needs a breakthrough in the current development limitations and then becomes more accurate and integrated. This paper proposes a theoretic framework and finite element implementation on progressive collapse...

Recent forensic studies have revealed quite a few construction site catastrophes are associated with failure of temporary structures (e.g., collapse of formworks, scaffoldings, etc.). This is particularly crucial for those located in dense urban areas where the failure of a temporary structure not only impacts the site itself but may also damage ad...

Image-based 3D reconstruction of civil infrastructure is an emerging topic that is gaining significant interest both in the scientific and commercial sectors of the construction industry. Reliable computer vision-based algorithms have become available over the last decade and they can now be applied to solve real-life problems in uncontrolled envir...

Work-related musculoskeletal disorders (WMSDs) have long been a primary cause of non-fatal injuries in construction. They involve sudden or continuous stresses on a worker's musculoskeletal system (e.g., muscles, tendons, ligaments, bones) and may impair the ability of the worker to perform his or her job, or even cause permanent disability. Althou...

As a major risk factor of low back injury, sudden loading often occurs when performing manual material-handling tasks on uneven ground surfaces. Therefore, the purpose of the current study was to investigate the effects of a laterally slanted ground on trunk biomechanical responses during sudden loading events. Thirteen male subjects were subjected...

Temporary structures, such as formwork support and scaffolding, play an important role in on-site production for construction projects. However, they are normally disregarded when considering the importance of qualifications and experience. In fact, most of the time, temporary structures won't be considered until it is actually constructed. As a re...

In construction photogrammetric surveying, it is imperative to convert the relative scale of a 3D model into absolute measurements so that geometric measurements can be taken. Previous work suggests this can be done through the determination of a reference line in absolute units, but the position and quantity of reference lines has not been investi...

This paper presents research on the mechanism of overturning failure on box girder under overload and partial load for the single-column pier bridges. It includes: (1) the definition of two key states before the box girder overturns (i.e., the disengaging state leading to the unbalanced load bearing and the ultimate state of overturning stability;...

This paper reviews photogrammetric error sources and their impacts on modeling and surveying for construction quantity takeoff, quality control, and site safety monitoring applications. These error sources include camera internal parameters (i.e., type, principal point, principal distance, and camera lens distortion coefficients), imaging settings...

Three-dimensional (3D) modeling of site elements is beneficial to many construction management applications such as quantity takeoff and quality control. However, current practice lacks a solution that is computationally simple, cost effective, and easy to use in the field. This research proposes a 3D modeling method based on the mechanism of photo...

Cumulative trauma disorders (CTDs) are a leading cause of disability which generates huge direct and indirect costs in the construction industry. Existing efforts identify the risk of CTDs through survey or observatory studies which are subjective and expensive. This paper attempts to automatically identify the risk of CTDs on construction sites wi...

As-built spatial data are useful in many construction-related applications, such as quality control and progress monitoring. These data can be collected using a number of imaging and time-of-flight-based (e. g., laser scanning) sensor methods. Each application will demand a particular level of data accuracy and quality, yet little information is av...

Videogrammetry is an inexpensive and easy-to-use technology for 3D scene spatial recovery. When applied to civil infrastructure, the scale of the scene is significantly larger than manufacturing applications. As a result, it usually takes a long time to videotape the scene, leading to a large quantity of frames in the video. In most cases, only few...

The lack of viable methods to map and label existing infrastructure is one of the engineering grand challenges for the 21st century. For instance, over two thirds of the effort needed to geometrically model even simple infrastructure is spent on manually converting a cloud of points to a 3D model. The result is that few facilities today have a comp...

The US National Academy of Engineering recently identified restoring and improving urban infrastructure as one of the grand challenges of engineering. Part of this challenge stems from the lack of viable methods to map/label existing infrastructure. For computer vision, this challenge becomes "How can we automate the process of extracting geometric...

Automating the model generation process of infrastructure can substantially reduce the modeling time and cost. This paper presents a method to generate a sparse point cloud of an infrastructure scene using a sin-gle video camera under practical constraints. It is the first step towards establishing an automatic frame-work for object-oriented as-bui...

Timely and accurate evaluation of damage sustained by buildings after seismic events such as earthquakes or blasts is critical to determine the buildings’ safety and suitability for their future occupancy. Time used in conducting the evaluations substantially affects the duration for which the potentially damaged buildings remain unusable. The elap...

Camera motion estimation is one of the most significant steps for structure-from-motion (SFM) with a monocular camera. The normalized 8-point, the 7-point, and the 5-point algorithms are normally adopted to perform the estimation, each of which has distinct performance characteristics. Given unique needs and challenges associated to civil infrastru...

This paper proposes an analytical approach to incorporating computer-generated three-dimensional 3D graphics of invisible underground infrastructure into site photos so as to present a richer and more integral view of the site situation in construction engineering applications. The proposed approach simulates the image-forming process of a camera a...

The present research describes the fundamental working mechanism of photogrammetry and characterizes the errors of the photogrammetry-derived geometric measurements on building products in a systematic, practical, and statistically significant way. A site engineer simply takes snapshots of a building product with a digital camera from different ang...

To acquire information of the invisible underground infrastructure, non-destructive subsurface imaging technologies are generally utilized. In construction, the recorded data of as-built pile excavation is archived in Koden test result sheets. The test result is in the form of literal document and identified by the pile numbering. The graphical pre...

The application of artificial neural network (ANN) in the discipline of geotechnical engineering is discussed in this paper. A multi-layer error back-propagation (BP) feed-forward neural network model was proposed to predict an important geotechnical parameter, namely the consolidation coefficient. The conventional methods for predicting consolidat...

D models of building components or construction re- sources have been largely created by computer-aided- design (CAD) or by proprietary code for virtual reality de- velopment. Such 3D modeling methods entail accurate de- finition of points, lines and their relationships in the spatial coordinate system. Unlike CAD modeling, the surveying technique...

The absence of a valid resource-constrained critical path method (CPM) not only hampers the widespread use of mainstream project scheduling software in construction management practice, but also destabilizes the very foundation of any sophisticated, CPM-based time or cost analysis in construction scheduling research. This has motivated us into deve...

By integrating the vehicle tracking system, discrete-event simulation algorithm, and evolutionary optimization algorithm, we developed HKCONSIM-Realtime, a decision-support platform created specifically for handling ready-mixed concrete operations. This platform is capable of (1) tracking the positions of concrete trucks and monitoring the motion a...

xviii, 135 leaves : ill. (some col.) ; 30 cm. PolyU Library Call No.: [THS] LG51 .H577P CSE 2010 Dai The surveying technique of close-range photogrammetry is based on an analytical representation of the image forming mechanism of photography and extracts spatial information through computation on photos. This research reviews the fundamentals of cl...