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Dissertação de mestrado integrado em Engenharia Mecânica, A segurança rodoviária é fortemente dependente não só dos veículos circulantes, mas também dos dispositivos mecânicos existentes nas estradas. Assim, a avaliação do comportamento mecânico dos equipamentos de segurança rodoviária constitui uma tarefa de grande importância, que merece a atenção da Academia. Um exemplo destes equipamentos corresponde às barreiras de segurança rodoviária, dispostas junto às bermas das faixas de rodagem, sendo sua principal função a contenção das mais variadas tipologias de veículos, em caso de despiste. Este conjunto mecânico é categorizado segundo diferentes níveis de contenção que oferece, estando relacionados com diferentes graus de deformabilidade. Estes devem ser capazes não só de reter e redirecionar o veículo para a faixa de rodagem, mas também de assegurar que o evento não seja nem demasiado brusco, nem associado a desacelerações abruptas, de modo a não proporcionar danos corporais aos condutores e acompanhantes. Neste contexto, surge o método dos elementos finitos, que constitui uma ferramenta bastante útil tanto no projeto, como no desenvolvimento e avaliação de novas soluções construtivas, pelo que a sua utilização será fundamental no processo associado ao cumprimento dos níveis de desempenho exigidos pela legislação existente. Esta dissertação visa desenvolver modelos numéricos capazes de avaliar mecanicamente dois modelos de barreira de segurança rodoviária desenvolvidos para os níveis de contenção N2W2 e N2W3, aquando de um evento relacionado com o impacto de um veículo, definido de acordo com a normalização em vigor no nosso país. Estes eventos encontram-se dependentes de parâmetros relacionados com o tipo de veículo, com a sua velocidade de circulação, o ângulo de incidência da trajetória, entre outros, pelo que os ensaios utilizados na sua homologação deverão respeitar diretrizes estabelecidas pela norma EN 1317. Neste documento, para além da avaliação do comportamento mecânico dos conjuntos referidos, bem como do acordo numérico-experimental para os modelos de prumo analisados, foi ainda desenvolvido um estudo referente à interação destes componentes com vários tipos de solos. Posto isto, a partir dos modelos desenvolvidos, foram extraídos resultados relativos ao deslocamento máximo obtido na barreira, em resultado do impacto do veículo, sugerindo que nenhum dos modelos projetados (propostos pela empresa Metalogalva S.A.) permite alcançar o nível de contenção proposto, de acordo com as condições de certificação impostas pela norma EN 1317., Road safety is strongly dependent not only on the vehicles in circulation but also on the mechanical devices present on the roads. Therefore, assessing road safety mechanisms is a relevant task, that deserves Academy attention. An example of these mechanisms corresponds to road safety barriers, included on the sides of the carriageway, where their main function is to contain the most varied types of vehicles. This mechanical assembly is categorised according to different levels of containment related to different degrees of deformability. These must be able not only to retain and redirect the vehicle to the carriageway but also to ensure that this phenomenon is neither too abrupt, nor associated with sudden decelerations, so as not to provide bodily harm to drivers. The finite element method concerns a handy tool in the design, development and evaluation of new constructive solutions, so its use will be fundamental in the process associated with achieving the objectives. This dissertation aims to develop numerical models capable of mechanically evaluating two sets of road safety barriers, developed for containment levels N2W2 and N2W3, at the time of an impact event defined according to the indicated standardisation used in our country. These events depend on parameters related to the type of vehicle, its speed of movement, its angle of impact, among other things, so the tests used in their approval must comply with these guidelines. In this document, in addition to the mechanical assessment of the road safety barriers and the numerical-experimental agreement for the analysed prop models, a study concerning the interaction of these components with various types of soils was also conducted. After the development of the numerical models, the results of the maximum displacement obtained in the barrier at the end of the simulated event were extracted and they suggest that none of the models designed (proposed by Metalogalva S.A. company) for the proposed level of containment fully complied with the certification conditions imposed by the standard., Este trabalho teve o apoio da ANI – Agência Nacional de Inovação, através do projeto com a referência COMPETE-2020/03/SI/2017 Nº033497, intitulado “Barreiras de segurança rodoviária”, com acrónimo “BarRod”, através do Programa Operacional Competitividade e Internacionalização e o Programa Operacional Regional de Lisboa, apoiada pelo FEDER.

In this study, we consider the third order nonlinear Schrodinger equation (TONSE) that models the wave pulse transmission in a time period less than one-trillionth of a second. With the help of the extended modified method, we obtain numerous exact travelling wave solutions containing sets of generalized hyperbolic, trigonometric and rational solutions that are more general than classical ones. Secondly, we construct the transformation groups which left the equations invariant and vector fields with the Lie symmetry groups approach. With the help of these vector fields, we obtain the symmetry reductions and exact solutions of the equation. The obtained group-invariant solutions are Jacobi elliptic function and exponential type. We discuss the dynamic behaviour and structure of the exact solutions for distinct solutions of arbitrary constants. Lastly, we obtain conservation laws of the considered equation by construing the complex equation as a system of two real partial differential equations (PDEs).

As cloud adoption increases, so does the threats. Cloud security has become a key pillar to deliver critical business applications. In this incipient research we explore what technologies we count on to shift-left the security in cloud applications, helping to enforce security controls in a preventive manner and hence avoid deploying exploitable cloud resources. We classify and compare these technologies according to a proposed taxonomy, and reason about the limitations found. We identify what features a security control-enforcing technology should exhibit, and outline future research direction.

Dissertação de mestrado integrado em Engenharia Mecânica (área de especialização em Sistemas Mecatrónicos), The most important aspect when developing roads is safety. This factor represents a notable cost in development activities involving the construction of highways, and is, therefore, a factor widely studied in the academic community as well. As it is known, the finite element method is used to predict and simulate different phenomena in engineering applications, being increasingly used because it represents a significant cost savings, as it replaces the execution of experimental tests at full scale. Furthermore, it allows for geometric, behavioural (material) and boundary conditions definition changes. Finite element modelling also allows for calculations that involve the rigorous evaluation of fundamental engineering quantities, which in a mechanical test can be difficult to obtain or measure, because they are difficult to access or because they require equipment with limited access. For the modelling of the different components that make up the safety barrier model studied in this work, the Solidworks software was used, with the Sheet Metal tool, which allows to model the geometry in a similar way to the forming process. In the numerical simulation two approaches are presented. The first employs three-dimensional elements and solid screws in bolted connections. The second uses shell elements and connectors (connection functionalities) available in the finite element software libraries used. As the first approach did not achieve the desired success, the second approach constitutes a more detailed analysis for modelling an impact test. In addition to developing a model for future analysis of the barrier under study, an analysis of two modelling techniques that uses scripting and an interface is also carried out. The main limitation of this study is that it was not possible to validate the numerical model with experimental information, given the logistics involved. However, by comparing the information available in the literature, and analysing the current standards for the production of the studied containment solution, it was possible to conclude that the work carried out led to the production of a set of very consistent results., O aspeto mais importante aquando do desenvolvimento de estradas é a segurança. Este fator representa um custo destacável nas atividades de desenvolvimento que envolvem a construção de rodovias, sendo por isso um fator amplamente estudado também na comunidade académica. Como é sabido, o método dos elementos finitos é utilizado para prever e simular fenómenos diversos em aplicações de engenharia, sendo cada vez mais utilizado por representar uma poupança de custos significativa, pois substitui a execução de ensaios experimentais à escala real. Além disto, permite a realização de alterações geométricas, comportamentais (materiais) e de definição de condições de fronteira. A modelação por elementos finitos permite também a realização de cálculos que envolvem a avaliação rigorosa de grandezas fundamentais em engenharia, que num ensaio mecânico podem ser difíceis de obter ou medir, por serem de difícil acessibilidade ou por requerem equipamentos de acesso limitado. Na modelação dos diferentes componentes que constituem o modelo de barreira de segurança estudado neste trabalho, empregou-se o software Solidworks, com a ferramenta Sheet Metal, que permite modelar a geometria de uma maneira semelhante ao processo de conformação. Na simulação numérica são apresentadas duas abordagens. A primeira emprega elementos tridimensionais e parafusos sólidos nas ligações aparafusadas. A segunda recorre a elementos de casca e conectores (funcionalidades de ligação) disponíveis nas livrarias do software de elementos finitos utilizado. Sendo que na primeira abordagem não se alcançou o sucesso desejado, a segunda abordagem constitui uma análise mais detalhada para a modelação de um ensaio de impacto. Além de desenvolver um modelo para futuras análises à barreira em estudo, é também feita uma análise a duas técnicas de modelação que recorre a scripting e a uma interface. A principal limitação deste estudo reside em não ter sido possível validar o modelo numérico com informação experimental, atendendo à logística envolvida. No entanto, por comparação com a informação disponível na literatura, e analisadas as normas vigentes para a produção da solução de contenção estudada, foi possível concluir que o trabalho desenvolvido conduziu à produção de um conjunto de resultados muito coerentes., This work was supported by “ANI – Agência Nacional de Inovação”, through the project with the reference “COMPETE-2020/03/SI/2017 Nº033497”, entitled “Barreiras de segurança rodoviária”, with the acronym “BarRod”, through the “Programa Operacional Competitividade e Internacionalização” and the “Programa Operacional Competitividade e Internacionalização e o Programa Operacional Regional de Lisboa”, supported by “FEDER”.

Safety barriers limit the severe consequences to occupants of vehicles leaving the roadway from colliding with obstacles, yet they may significantly reduce the available sight distance (ASD). A procedure was devised to accurately recreate highway guardrails in three dimensions (3D), fitting the barriers onto the curve roadsides. The effect of these devices on the reduction of the ASD was thus evaluated in a set of case studies comprising different curve radii overlapped with different vertical alignments and combined each with two safety barriers in two-lane rural roads. The 3D models of highway curves with the selected guardrails were created in a geographic information system. Then, a geoprocessing model was used to compute the ASD. The results made it possible to quantify the ASD reduction produced by the barrier with a higher containment level in relation to the highway design parameters, which can assist authorities in developing more comprehensive safety device standards.

In this paper, a novel hybrid optimization algorithm is introduced by hybridizing a Harris hawks optimization algorithm(HHO) and simulated annealing for the purpose of accelerating its global convergence performance and optimizing structural design problems. This paper is the first research study in which the hybrid Harris hawks simulated annealing algorithm (HHOSA) is used for the optimization of design parameters for highway guardrail systems. The HHOSA is evaluated using the well-known benchmark problems such as the three-bar truss problem, cantilever beam problem, and welded beam problem. Finally, a guardrail system that has an H1 containment level as a case study is optimized to investigate the performance of the HHOSA. The guardrail systems are designed with different cross-sections and distances between the posts. TB11 and TB42 crash analyses are performed according to EN 1317 standards. Twenty-five different designs are evaluated considering weight, the guardrail working width, and the acceleration severity index (ASI). As a result of this research, the optimum design of a guardrail is obtained, which has a minimum weight and acceleration severity index value (ASI). The results show that the HHOSA is a highly effective approach for optimizing real-world design problems.

Although building information modeling (BIM) has been widely adopted in the building industry for several decades, the use of BIM in the context of transportation infrastructure has been slow in terms of both adoption and application. Industry and academia are increasingly making efforts to adopt BIM for other non-building civil infrastructure but, so far, there has not been a comprehensive review of these efforts specifically regarding transportation. This paper explores BIM implementation in an infrastructure design project. An Autodesk &reg, BIM-based tool, Civil 3D, is proposed as a potential BIM tool platform. This paper also focuses on modeling specific road elements not editable from the standard library, such as guardrails and retaining walls, as well as proposing different solutions using Revit and Subassembly Composer and analyzing the interoperability among BIM-based tools.

Barriers (guardrails and balustrades) prevents people from falling, for example, from balcony, open windows and stairs. Barriers also retain, stop or guide person in buildings. To increase the transparency of these components, traditional materials such as bricks, wood and metal are being replaced by glass or an organic material, which has mechanical behavior different from traditional materials. Regulation usually specify some action to take into account in the design of barriers, but do not define the required resistance. There are no international standards (ISO or EN) to assess the fitness for use of barriers, only national standards, with different testing loading conditions and mechanical resistance requirements. In this paper is presented a comparison of requirements and experimental testing conditions specified in standards from Portugal, Spain, France, UK, USA and Brazil. The goal of this research is to find some equivalence between standards, regarding the mechanical resistance behavior of different materials (brittle/ductile materials) and set a worst case scenario as the basis for the guardrails mechanical resistance profile. Some relations between the service limits state (plasticity) of metal guardrails and maximum deflection are proposed.

In this work were obtained by Operational Modal Analysis (OMA) vibration modes and frequencies associated with temporary of protection systems (TEPS) built with planks of pine wood and steel poles. These systems have been evaluated analytically, using a finite element model (FEM). For the FEM we obtained the elastic constants of wood using ultrasound. The results of experimental and analytical assessment in the first vibration modes match in reasonable ways., En este trabajo se han obtenido experimentalmente mediante Análisis Modal Operacional (AMO) los modos de vibración y las frecuencias asociadas de sistemas provisionales de protección de borde (SPPB) fabricados con tablas de madera de pino silvestre y postes de sección tubular de acero. Los mismos sistemas se han evaluado analíticamente, usando un modelo de elementos finitos (MEF). Para el MEF se han obtenido las constantes elásticas de la madera mediante ultrasonidos. Los resultados de la evaluación experimental y analítica concuerdan en los primeros modos de vibración.

Bridges that are designated historic present a special challenge to bridge engineers whenever rehabilitation work or improvements are made to the bridges. Federal and state laws protect historically significant bridges, and railings on these bridges can be subject to protection because of the role they play in aesthetics. Unfortunately, original railings on historic bridges do not typically meet current crash-test requirements and typically do not meet current standards for railing height and size of permitted openings. The objective of this study is to develop strategies that can be used to address existing railings on historic bridges and to develop solutions that meet current design requirements. To achieve this objective, three phases of research were conducted. First, an overview of current practice for addressing historic bridge railings was performed. Second, an investigation was conducted to document historic bridge railings in Indiana. Finally, rehabilitation solutions were developed to address the specific bridge railings found in Indiana. Based on this research, three retrofit strategies were developed which include an inboard railing, curb railing, and a simulated historic railing. These rehabilitation solutions can be used to address historic bridge railings not only in Indiana, but across the country.

To protect themselves against fall hazards in a slab-column frame, workers use the row of shoring jacks installed at 1 m from the edge as supports for on-site built guardrails. Inspectors of the Quebec Workers Compensation Board (Commission de la santé et de la sécurité du travail (CSST)) have expressed concern about the safety and compliance of these on-site built guardrails with the Quebec Safety Code for the Construction Industry (S-2.1, r.4). Some workers have also inquired if the shoring jack can be used as an anchor for a travel restraint system. The present study describes how an evaluation method and a test protocol have been used to verify if guardrails built on-site, with shoring jacks as supports, are safe and comply with the requirements of S-2.1, r.4 and if the shoring jack can be used as an anchor point for a travel restraint system. The results of the study show 1) guardrails built on site with shoring jacks as supports, are safe and comply with S-2.1, r.4 and 2) shoring jacks used as supports for guardrails must not be used as an anchor for a travel restraint system., Para la protección contra el peligro de caída en altura durante la ejecución de la estructura de un edificio, los trabajadores utilizan puntales acodalados a dos forjados y situados a 1 metro del borde de forjado como apoyo de las barandillas de seguridad. Inspectores de la Quebec Workers Compensation Board (Commision de la santé et de la sécurité du travail (CSST)) han expresado su preocupación por la seguridad y el cumplimiento de estos sistemas de protección en la construcción conforme al Código de Seguridad de Quebec para la industria de la construcción (S-2.1, R.6). Así mismo algunos trabajadores han mostrado su inquietud sobre la utilización de los puntales como sistemas para limitar el desplazamiento. El presente estudio describe un método de evaluación y un procedimiento de ensayo que se han utilizado para verificar si las barandillas de seguridad apoyadas en puntales acodalados son seguras y cumplen con los requisitos de S-2.1, R.6; y si el puntal acodalado puede ser utilizado como punto de anclaje del sistema para limitar los desplazamientos. Los resultados del estudio muestran 1) las barandillas de seguridad apoyadas en puntales acodalados son seguras y cumplen con S-2.1, R.6 y 2) los puntales acodalados utilizados como apoyo de las barandillas de seguridad no deben ser usados como apoyos para sistemas con desplazamientos limitados.

Construction safety regulations require protection of workers against falls from elevations. The collective fall protection systems, in most cases, allow workers to move freely without wearing individual fall protection gear. The collective systems which prevent falls are preferred over the fall arrest systems. The latter are employed only if prevention of falls is not feasible. Arresting a fall always carries with it a residual risk of injury to the fall victim. The collective fall arrest systems are employed primarily during construction of electricity or telecomm towers. The aim of this paper has been a review of the collective FPS employed in the construction industry., Las normas de seguridad en la construcción requieren de protección para los trabajadores contra las caídas desde altura. Los Sistemas de Protección contra Caídas (FPS, por sus siglas en inglés) colectivos, en la mayoría de los casos, permiten que los trabajadores se muevan libremente sin usar un equipo de protección contra caídas individual. Los sistemas colectivos de prevención de caídas son preferibles a los sistemas de detención de caídas, estos últimos se emplean sólo si la prevención de las caídas no es factible. La detención de una caída siempre lleva consigo un riesgo residual de lesiones en la víctima accidentada. Los sistemas colectivos de detención de caídas se emplean principalmente en la construcción de torres de electricidad o telecomunicaciones. El objetivo de este trabajo ha sido la revisión de los sistemas colectivos de protección contra caídas empleados en la industria de la construcción.

This report provides information on the design considerations of the embedded highway lighting design on Interstate-25 in Trinidad, Colorado, in terms of visibility. The information is based on visibility characterizations of small targets using luminance, illuminance, and contrast calculations as well as participant input on the detectability of small targets. Experimental conditions included two different aim angles of the lighting design (forward and cross) as well as two small target colors (red and blue). When compared to the small target detection distances produced by conventional overhead lighting systems in previous studies, the research determined that the small target visibility distances of the embedded lighting design to be shorter by approximately 50%. Adjustments to the spacing, aim, and breadth of the lighting design are recommended for future research considerations. Implementation The results of this research indicate the lighting design is an alternative; however, additional considerations to the beam angle, beam width, beam height, and spacing may improve the implementation of the system. Colorado. Department of Transportation

Ljudje se vsakodnevno srečujemo s cestnim prometom, zato je varnost na cestah izrednega pomena. Na varnost ceste vpliva tudi vsa prometna oprema, ki je prisotna na njej. Pomembnost prometne opreme se na cestah, ki so v slabšem stanju, še poveča. Pri vplivu na varnost je potrebno izpostaviti varnostne ograje, kot ene izmed pomembnejših vrst cestne opreme. S pomočjo pravilne postavitve in rednega vzdrževanja varnostnih ograj je mogoče omiliti posledice prometnih nesreč. V nalogi je opisana celotno cestna oprema, ki se uporablja v Sloveniji. Navedeni so kriteriji za uporabo prometne opreme na javnih cestah. Na osnovi praktičnih primerov je opozorjeno tudi na napake, ki se dogajajo v praksi. Every day we are in contact with the road transport. Road safety is also influenced by all the transport equipment, which is present on it. The importance of transport equipment is even more complex on roads in worse condition. The impact on security is necessary to highlight the safety barriers, as one of main types of road equipment. With proper installation and regular maintenance safety barriers can mitigate the effects of accidents. The thesis describes the entire road equipment, which is used in Slovenia. Those are the criteria related to the use of transport equipment on public roads. On the basis of practical examples is indicated on the errors that occur in practice.

In this work were obtained by Operational Modal Analysis (OMA) vibration modes and frequencies associated with temporary of protection systems (TEPS) built with planks of pine wood and steel poles. These systems have been evaluated analytically, using a finite element model (FEM). For the FEM we obtained the elastic constants of wood using ultrasound. The results of experimental and analytical assessment in the first vibration modes match in reasonable ways. En este trabajo se han obtenido experimentalmente mediante Análisis Modal Operacional (AMO) los modos de vibración y las frecuencias asociadas de sistemas provisionales de protección de borde (SPPB) fabricados con tablas de madera de pino silvestre y postes de sección tubular de acero. Los mismos sistemas se han evaluado analíticamente, usando un modelo de elementos finitos (MEF). Para el MEF se han obtenido las constantes elásticas de la madera mediante ultrasonidos. Los resultados de la evaluación experimental y analítica concuerdan en los primeros modos de vibración.

The cost of a road construction over its service life is a function of design, quality of construction as well as maintenance strategies and operations. An optimal life-cycle cost for a road requires evaluations of the above mentioned components. Unfortunately, road designers often neglect a very important aspect, namely, the possibility to perform future maintenance activities. Focus is mainly directed towards other aspects such as investment costs, traffic safety, aesthetic appearance, regional development and environmental effects. This doctoral thesis presents the results of a research project aimed to increase consideration of road maintenance aspects in the planning and design process. The following subgoals were established: Identify the obstacles that prevent adequate consideration of future maintenance during the road planning and design process; and Examine optimisation of life-cycle costs as an approach towards increased efficiency during the road planning and design process. The research project started with a literature review aimed at evaluating the extent to which maintenance aspects are considered during road planning and design as an improvement potential for maintenance efficiency. Efforts made by road authorities to increase efficiency, especially maintenance efficiency, were evaluated. The results indicated that all the evaluated efforts had one thing in common, namely ignorance of the interrelationship between geometrical road design and maintenance as an effective tool to increase maintenance efficiency. Focus has mainly been on improving operating practises and maintenance procedures. This fact might also explain why some efforts to increase maintenance efficiency have been less successful. An investigation was conducted to identify the problems and difficulties, which obstruct due consideration of maintainability during the road planning and design process. A method called “Change Analysis” was used to analyse data collected during interviews with experts in road design and maintenance. The study indicated a complex combination of problems which result in inadequate consideration of maintenance aspects when planning and designing roads. The identified problems were classified into six categories: insufficient consulting, insufficient knowledge, regulations and specifications without consideration of maintenance aspects, insufficient planning and design activities, inadequate organisation and demands from other authorities. Several urgent needs for changes to eliminate these problems were identified. One of the problems identified in the above mentioned study as an obstacle for due consideration of maintenance aspects during road design was the absence of a model for calculating life-cycle costs for roads. Because of this lack of knowledge, the research project focused on implementing a new approach for calculating and analysing life-cycle costs for roads with emphasis on the relationship between road design and road maintainability. Road barriers were chosen as an example. The ambition is to develop this approach to cover other road components at a later stage. A study was conducted to quantify repair rates for barriers and associated repair costs as one of the major maintenance costs for road barriers. A method called “Case Study Research Method” was used to analyse the effect of several factors on barrier repairs costs, such as barrier type, road type, posted speed and seasonal effect. The analyses were based on documented data associated with 1625 repairs conducted in four different geographical regions in Sweden during 2006. A model for calculation of average repair costs per vehicle kilometres was created. Significant differences in the barrier repair costs were found between the studied barrier types. In another study, the injuries associated with road barrier collisions and the corresponding influencing factors were analysed. The analyses in this study were based on documented data from actual barrier collisions between 2005 and 2008 in Sweden. The result was used to calculate the cost for injuries associated with barrier collisions as a part of the socio-economic cost for road barriers. The results showed significant differences in the number of injuries associated with collisions with different barrier types. To calculate and analyse life-cycle costs for road barriers a new approach was developed based on a method called “Activity-based Life-cycle Costing”. By modelling uncertainties, the presented approach gives a possibility to identify and analyse factors crucial for optimising life-cycle costs. The study showed a great potential to increase road maintenance efficiency through road design. It also showed that road components with low investment costs might not be the best choice when including maintenance and socio-economic aspects. The difficulties and problems faced during the collection of data for calculating life-cycle costs for road barriers indicated a great need for improving current data collecting and archiving procedures. The research focused on Swedish road planning and design. However, the conclusions can be applied to other Nordic countries, where weather conditions and road design practices are similar. The general methodological approaches used in this research project may be applied also to other studies. QC 20110407