<p>  </p> <p>Hazard identification is one of the most significant components in safety management at construction jobsites to prevent undesired fatalities and injuries of construction workers. The current practice, which relies on a limited number of safety managers’ manual and subjective inspections, and existing research efforts analyzing workers’ physical and physiological signals have achieved limited success, leaving many hazards unidentified at the jobsites. Motivated by this critical need, this research aims to develop a human sensing network that allows for ubiquitous hazard identification in the construction workplace.</p> <p>To attain this overarching goal, this research analyzes construction workers’ collective EEG signals collected from wearable EEG sensors based on machine learning, virtual reality (VR), and advanced signal processing techniques. Three specific research objectives are: (1) establishing a relationship between EEG signals and the existence of construction hazards, (2) identifying correlations between EEG signals/physiological states (e.g., emotion) and different hazard types, and (3) developing an integrated platform for real-time construction hazard mapping and comparing the results developed based on VR and real-world experimental settings.</p> <p>Specifically, the first objective establishes the relationship by investigating the feasibility of identifying construction hazards using a binary EEG classifier developed in VR, which can capture EEG signals associated with perceived hazards. In the second objective, correlations are discovered by testing the feasibility of differentiating construction hazard types based on a multi-class classifier constructed in VR. In the first and second objectives, the complex relationships are also analyzed in terms of brain dynamics and EEG signal components. In the third objective, the platform is developed by fusing EEG signals with heterogeneous data (e.g., location), and the discrepancies in VR and real-world environments are quantitatively assessed in terms of hazard identification performance and human behavioral responses.</p> <p>The primary outcome of this research is that the proposed approach can be applied to actual construction jobsites and used to detect all potential hazards, which was challenging to be achieved based on the current practice and existing research efforts. Also, the human cognitive mechanisms revealed in this research discover new neurocognitive knowledge in construction workers’ hazard perception. As a result, this research contributes to enhancing current hazard identification capability and improving construction workers’ safety and health.</p>

Submitted in fulfillment for the degree of Magister Technologiae: Engineering: Civil, Durban University of Technology, Durban, South Africa, 2013. / An increase in road traffic, poor road conditions and high numbers of road accidents are major challenges at the Port of Durban. Roads are considered as the most important transport mode at the Port of Durban. Road transport has taken almost 80% of the import and export cargo while railway transport is left with approximately 20%. It is estimated that 75 million lives in the world will be lost and 750 million people injured in road accidents in the first half of the 21th century. The Port of Durban is an important vehicle for facilitating economic growth of local, regional and national industries. For the Port to maintain global competitiveness with the current trend of globalization, it has to ensure that roads are well maintained, safe and have a smooth traffic flow with no delays. This study provides an overview of the road infrastructure within the Port of Durban in relation to road condition, safety, law enforcement and traffic. Existing and ongoing studies conducted in South Africa and abroad form part of the literature review. This study identifies factors that are affecting the condition of road infrastructure such as growth of container cargo, an increase in the dimension and weight of trucks, transport deregulation, port layout and handling equipments. Deregulation of road transport over the past years has resulted in an 80:20 split between road and rail transport putting more pressure on roads. Cost and time are the major deciding factors in the freight industry. Most customers prefer to use road transport due to the lower cost and reduced time compared to rail transport. There are eight major roads within the Port that connect the South, West and North of eThekwini Municipality namely Bayhead, Quayside, Maydon, Rick Turner, Wisely, South Coast, Bluff and Iran Roads. Asset verification and assessment of the condition of the existing eight major roads found that Quayside Road is in a better condition compared to the other roads. Maydon and South Coast Roads are low rated roads which are in a poor condition. Identification and assessment of the condition of 210 000m² of asphalt paved areas which included minor roads within the Port of Durban was also conducted. Most paved areas and roads fall under D (fair) category which is reasonable but maintenance work may be required within six months. Comparison between the condition of the eight major roads within the Port and outside the Port was investigated. The findings indicate that sections of roads outside the Port are in a better condition than sections within the Port. Traffic counts were conducted in order to determine the utilization of the existing eight major roads. Bayhead and South Coast Road are highly utilized roads. Road accident reports and death reports were analyzed on these roads. Most of the road accidents take place on South Coast Road. A questionnaire survey was conducted, targeting road users who travel on these roads within the Port. Feedback was obtained on the status of road conditions, safety and traffic within the Port of Durban. Findings of this survey revealed that most of the respondents don’t know where to report road defect/s within the Port. Approximately 37.5% of the road users felt not safe to drive on roads within the Port especially on South Coast Road. A high percentage of people (93%) witnessed accidents on these roads. Traffic signals within the Port are maintained by eThekwini Municipality and are very often non-functional. When road signs need to be repaired or replaced, it takes longer than expected. Also, there are limited parking areas around the Port resulting in trucks parking closer to the premises while waiting to collect or deliver cargo. This causes major traffic congestion, for example, on Maydon Road where most trucks park on the side of the road. Recommendations include assessment guidelines that could improve road condition, safety and traffic flow. Areas to be improved with regard to road infrastructure are also highlighted. / M

Transportation safety is a highly contentious issue in the design of cities and communities. To enhance community livability, urban designers, architects and city planners often encourage the placement of street trees, aesthetic street lights, and other roadside features in a buffer zone between the pedestrian realm and the vehicle travelway. While such designs clearly enhance the aesthetic quality of a roadway, conventional geometric design practice regards roadside features located in the clear zone as fixed-object hazards, and strongly discourages their use. This study examines roadside safety in urban environments to better understand the nature of urban fixed-object crashes, as well as the safety impacts of livable streetscape treatments. While the prevailing assumption is that livable street treatments have a negative impact on a roadways safety performance, the existing empirical evidence indicates that such designs are much safer than more conventional roadside designs. Current safety objections to the use of livable street treatments are not based on empirical evidence, but are instead the result of a design philosophy that systematically overlooks the real-world operating behavior of road users. This study details the origin and evolution of this philosophy, termed passive safety, and subjects it to an empirical test to evaluate its applicability to urban arterial roadways. It finds that passive safety assumptions do not meaningfully explain empirical observations of crash frequency and severity. To enhance contemporary geometric design practice, this study then proceeds to more thoroughly examine the nature and characteristics of urban roadside crashes, and proposes a new design approach, termed positive design that better addresses the twin goals of safety and livability.

Many robotic systems are remotely operated nowadays that require uninterrupted connection and safe mission planning. Such systems are commonly found in military drones, search and rescue operations, mining robotics, agriculture, and environmental monitoring. Different robotic systems may employ disparate communication modalities such as radio network, visible light communication, satellite, infrared, Wi-Fi. However, in an autonomous mission where the robots are expected to be interconnected, communication constrained environment frequently arises due to the out of range problem or unavailability of the signal. Furthermore, several automated projects (building construction, assembly line) do not guarantee uninterrupted communication, and a safe project plan is required that optimizes collision risks, cost, and duration. In this thesis, we propose four pronged approaches to alleviate some of these issues: 1) Communication aware world mapping; 2) Communication preserving using the Line-of-Sight (LoS); 3) Communication aware safe planning; and 4) Multi-Objective motion planning for navigation. First, we focus on developing a communication aware world map that integrates traditional world models with the planning of multi-robot placement. Our proposed communication map selects the optimal placement of a chain of intermediate relay vehicles in order to maximize communication quality to a remote unit. We also vi propose an algorithm to build a min-Arborescence tree when there are multiple remote units to be served. Second, in communication denied environments, we use Line-of-Sight (LoS) to establish communication between mobile robots, control their movements and relay information to other autonomous units. We formulate and study the complexity of a multi-robot relay network positioning problem and propose approximation algorithms that restore visibility based connectivity through the relocation of one or more robots. Third, we develop a framework to quantify the safety score of a fully automated robotic mission where the coexistence of human and robot may pose a collision risk. A number of alternate mission plans are analyzed using motion planning algorithms to select the safest one. Finally, an efficient multi-objective optimization based path planning for the robots is developed to deal with several Pareto optimal cost attributes.

In the U.S., construction accidents remain a significant economic and social problem. Despite recent improvement, the Construction industry, generally, has lagged behind other industries in implementing safety as a total management process for achieving zero accidents and developing a high-performance safety culture. One aspect of this total approach to safety that has frustrated the construction industry the most has been “measurement”, which involves identifying and quantifying the factors that critically influence safe work behaviors. The basic problem attributed is the difficulty in assessing what to measure and how to measure it – particularly the intangible aspects of safety. Without measurement, the notion of continuous improvement is hard to follow. This research was undertaken to develop a strategic framework for the measurement and continuous improvement of total safety in order to achieve and sustain the goal of zero accidents, while improving the quality, productivity and the competitiveness of the construction industry as it moves forward. The research based itself on an integral model of total safety that allowed decomposition of safety into interior and exterior characteristics using a multiattribute analysis technique. Statistical relationships between total safety dimensions and safety performance (measured by safe work behavior) were revealed through a series of latent variables (factors) that describe the total safety environment of a construction organization. A structural equation model (SEM) was estimated for the latent variables to quantify relationships among them and between these total safety determinants and safety performance of a construction organization. The developed SEM constituted a strategic framework for identifying, measuring, and continuously improving safety as a total concern for achieving and sustaining the goal of zero accidents.

Syftet med denna studie är att undersöka faktorer som påverkar adoptionen av drönare för säkerhetsskäl på byggarbetsplatser, och att fastställa hur dessa faktorer påverkar adopteringen. Detta bidrar till att teknologiskt modernisera byggbranschen samt fylla en lucka i befintlig litteratur om adoptionen av drönare för säkerhetsskäl. För att undersöka detta genomfördes elva semistrukturerade intervjuer med personer som representerade åtta olika företag av varierande storlek, alla aktiva i byggindustrin. Resultaten indikerar att de primära faktorer som påverkar adopteringen är 1) Kännedom, 2) Organisation, 3) Arbetarna, 4) Genomförbarhet och 5) Extern miljö. Alla dessa faktorer kan påverka adoptionen såväl positivt som negativt. Hur dessa faktorer påverkar adoptionen av drönare har också modellerats i det framtagna ramverket Drone Adoption Model (DAM). Adoptionsprocessen inleds med att Intresset sprids inom företaget. När intresset är etablerat görs en Genomförbarhetsbedömning. Beroende på resultatet från genomförbarhetsbedömning pilottestas tekniken, vilket sedan lägger grunden för Diffusionen. De olika faktorerna påverkar adoptionen i olika faser. Kännedom påverkar primärt adoptionen i Intressefasen. Faktorerna genomförbarhet och organisation påverkar adoptionen primärt i genomförbarhetsbedömningen. Slutligen påverkar faktorerna Arbetarna och Extern miljö genom hela processen. / The aim of this study is to explore, understand and elucidate the factors that influence the adoption of drones for safety purposes on outdoor construction sites, as well as to determine how these factors influence adoption. This contributes to the role of modern technologies in the construction industry as well as fill a gap in existing literature of drone adoption for safety purposes. In order to investigate this, eleven semi-structured interviews were conducted with people representing eight different companies of varying size, all active in the construction industry. The results indicate that the major factors influencing adoption are: 1) Awareness, 2) Organization, 3) Workers, 4) Feasibility and 5) External environment. All these factors could influence the adoption both positively and negatively. How the factors influence the adoption has been modelled in the proposed framework Drone Adoption Model (DAM). The adoption process starts with Interest being spread throughout the firm. Once an interest is established, a Feasibility assessment is conducted. Depending on the result from the feasibility assessment, the technology is Pilot tested, which then lays the foundation for the Diffusion. The different factors influence adoption in different phases. Awareness primarily influence adoption in the Interest phase, whereas the factors Feasibility and Organization influence adoption mainly in the Feasibility assessment. Lastly, the two factors external environment and workers influence the adoption throughout the whole process.

Though the trucks consist of only 3% of the total registered vehicles in the United States, truck accidents have been a major concern due to the property damage and loss of lives involved. Growth trends show that the truck travel will reach 1 trillion vehicle miles by the end of the year 2000. This increase in truck travel poses a major threat to the safety of both passenger cars and trucks. To improve the safety of the trucks as well as the passenger cars, understanding of the factors affecting the truck safety is essential. Models developed in the past were mostly regression models which tried to relate the truck accidents to the geometry of the highways. But most of these models did not consider all the factors affecting the safety of the trucks. Simulation models were developed in the past to study the dynamic vehicle response to different highway geometry especially, on exit ramps where most of the rollover accidents occur every year. But not enough research was done in the past on the weather and surface conditions affecting the truck safety. The objective of this study is to develop a graphics-based computer simulation model to test the trucks for different geometric features, surface conditions, and truck characteristics on exit ramps and to gain a better understanding of the factors affecting the safety of the trucks. A high-level simulation language SIMSCRIPTII.5 was used in the study to develop a simulation model. To make the model is to understand, graphical windows and animation were included in the model. Three exit ramps were tested in this model. Two of these ramps are existing ramps in southwestern Virginia and they had rollover accidents reported on them in the past. The parameters and other surface and geometric conditions can be changed at any time during the simulation. The model indicated that deceleration lengths provided may not be sufficient for heavy trucks traveling at higher speeds to reduce their speeds to the safe speed limits on the ramps. The posted speed limits may not be suitable for heavy trucks especially when the surface is not dry. The model also indicated that the tractor-semitrailers are more exposed to rollovers than any other type of trucks. / Master of Science

On-the-job injuries that occur even after implementing safety interventions highlight the need for identifying the limitations in them and for making future safety interventions and technological advances more effective. One possible reason for this lower-than-expected-safety returns is the latent side-effect of safety interventions, known as risk compensation. This dissertation aimed to provide empirical evidence and theoretical considerations of risk compensation effect in the construction industry. Accordingly, a multi-sensor immersive mixed-reality environment consists of a virtual projection of the environment and passive haptics of a roof was developed to study risk compensation among residential roofers. Simulating height, environmental factors (wind and sound), passive haptic, and virtual falls stimulated sufficient Sense of Presence to trigger subjects' behavioral changes while installing shingles on a 27-degree sloped roof under three levels of safety interventions (i.e., with no fall-safety intervention, with an injury-reducing fall-safety intervention—i.e., fall-arrest system—and with an injury-preventing fall-safety intervention— i.e., a fall-arrest system and a guardrail). The baseline demographic, psychographic, and cognitive measures combined with real-time tracking and wearable sensors provided an opportunity to track the worker's motions, localize his/her position, obtain real-time musculoskeletal data, and monitor the his/her behavioral and physiological responses. The collected data is then translated into information about the risk perception and risk-taking behavior of the worker. The results yielded unequivocal evidence of risk compensation—the lower perceived risk associated with the situation (lower levels of stress) and the false sense of security among roofers when they were provided with safety interventions apparently encouraged them to be less cautious by leaning over the edge, stepping closer to the roof edge, spending more time exposing themselves to fall risk, over-relying on the safety equipment through different facing directions and choices of posture stability. As a result, they also experienced more near-misses (close calls). This behavioral adaptation was more pronounced when they were provided with an injury-preventing safety intervention (e.g., guardrail). The findings also suggested that the productivity and safety benefits of safety interventions can be negated due to risk compensation, which identifies vital information for the construction-safety community to consider during the design and implementation of more effective safety interventions and technological advances. Roofers with high risk tolerance and sensation seekers were identified as high-risk groups who are more likely to be involved in risk-compensatory behaviors; various behavioral interventions are suggested in this dissertation to counteract excessive risk-taking and to reduce risk compensation. The findings of this study shed light on the question of why injury rates have remained at worrisome levels despite advances in protective measures and interventions. In the long-term, a better understanding of risk compensation will translate into fundamental knowledge about how the construction industry should approach and maintain controls after safety interventions. / Doctor of Philosophy / While researchers have dispensed considerable efforts to reduce the risk of occupational injuries by implementing safety interventions, the large number of safety incidents occurring each year in the construction industry. It is hypothesized that the latent effect of safety interventions, known as risk compensation, might be a possible reason why many of the safety interventions and technological advances have not fully achieved their safety objectives. This dissertation aimed to empirically examine the changes in workers' productivity, risk perception, risk-taking behaviors as a function of different safety interventions in place. To study this within a risk-free setting, an immersive mixed-reality environment simulating roofing task was developed. Then, the reactionary behavioral responses of participants were monitored using real-time tracking sensors and qualitative sources of data while they were completing a roofing task under three counterbalanced levels of safety interventions (i.e., with no fall-safety intervention, with an injury-reducing fall-safety intervention—i.e., fall-arrest system—and with an injury-preventing fall-safety intervention— i.e., a fall-arrest system and a guardrail). The findings indicated that the reduced perceived risk and the desire for increased productivity may skew risk analysis and strongly bias workers toward presuming invulnerability when safety interventions are in place. According to risk compensation theory, workers' risk tolerance and perceptions of risk influence their risk-taking behavior—as the perceived risk associated with the situation decreases, individuals take more risks to achieve a level of risk they can comfortably tolerate. Therefore, the workers might become less cautious by leaning over the edge, stepping closer to the roof edge, spending more time exposing themselves to fall risk, over-relying on the safety equipment through different facing directions and choices of posture stability. This result does not necessarily imply the safety innovations are completely ineffective, but rather demonstrates dangers users face when they misperceive the effectiveness of a safety intervention. Furthermore, roofers with high risk tolerance and a high sensation-seeking disposition were identified as high-risk groups who are more likely to be involved in risk-compensatory behaviors. This research represented a substantive departure from the status quo by proposing novel pathways for proactive incident prevention due to risk compensation in the construction industry. The contribution of this study is especially significant because a better understanding of risk compensation will translate into fundamental knowledge about how the construction industry should approach and maintain controls after safety interventions.

There are problems with poor quality, poor scheduling and poor working climate in the Swedish construction industry. Many parts have been involved, trying to solve the problem. This spring a new planning and building-law becomes final. In this law, the requirements set on the controls are greater. Hopefully this will lead to fewer construction errors. The requirements set on the working environment have also increased, forcing consultants and contractors to focus on safe workplaces. For each project requiring a building permit, an inspection plan has to been drawn. The inspection plan aims to ensure that the constructed building is operational. To ensure that the control plan is followed, self monitoring is performed. For each project, every designer also has to do a risk analysis to ensure a safe working environment. This report presents an investigation of stakeholders’ roles in the construction process. It also points out what by law should be controlled and against what. The result of the report is templates for control against PBL, self-monitoring plan and risk analysis. / Det finns stora problem med bristande kvalitet, dålig tidplanering och undermåligt arbetsmiljöklimat i den svenska byggbranschen. Detta problem är något som berörda parter lagt ner mycket tid på för att komma till rätta med. Som ett led i strävan mot kvalitetssäkring träder en ny Plan- och bygglag i kraft den 2 maj, som ökar kravet på innehåll i kontrollplaner, och därmed egenkontrollplaner. Arbetsmiljöfrågor har under senare år även de blivit mer aktuella med krav på byggarbetsmiljösamordnare och riskanalys. För samtliga projekt som kräver bygglov, rivningslov, marklov eller anmälan krävs en kontrollplan. Dessutom ska en egenkontrollplan samt en riskanalys finnas för samtliga projektörer i samtliga projekt. Riskanalyser ligger ofta till grund för val av lösningar eller omdirigeringar för att undvika personskador. I denna rapport redovisas en grundlig utredning av nyckelpersoners roll i kvalitets- och arbetsmiljöarbetet, samt vad som egentligen ska kontrolleras och mot vad. Nyckelpersonerna identifieras efterhand i rapporten. Resultatet av utredningen är förslag på utformning av mallar för kontrollplan-PBL, egenkontrollplan samt riskanalys.

This project focuses on the design and modeling of a two degree-of-freedom dissipative passive haptic display. Haptic displays are man-machine interfaces that transmit forces to the human operator. A dissipative passive haptic display is one that may only remove energy from the system using actuators such as brakes and dampers, thus ensuring the safety of the human operator. These devices may be used to implement virtual constraints such as desired paths and obstacles. Traditional friction brakes have previously been used as dissipative and coupling elements in a two degree-of-freedom parallel manipulator, resulting in undesired effects such as vibration, stiction, and slow response times. Alternatively, the new robot is actuated by rheological brakes, which feature fast response times and smooth application of torque. This approach aims to improve upon the accuracy and feel of the previous design. A commercial magnetorheological (MR) fluid brake was selected and put through an extensive series of tests. The data was used to develop a model that characterizes MR fluid behavior in low speed braking applications. A parallel five bar linkage was designed and built that has separate configurations corresponding to 3-brake and 4-brake operation. The length of each arm was chosen by means of a geometrical optimization that weighs the size and area of the workspace and actuator effects. A simulation was then developed by incorporating the brake model into the equations of motion of the robot. Next, two forms of path following velocity control were devised and tested in simulation. Finally, the accuracy, workload, and smoothness of both controllers and both configurations were examined in preliminary tests with human operators.