Given the large amount of construction and demolition waste (CDW) generated in the construction industry, as well as the constant need to extract natural aggregates (NA) from deposits on the planet (which are becoming scarcer every day), it is clear that it is necessary to invest in efficiently sustainable alternatives. One alternative that is often overlooked is the use of mixed recycled aggregates (MRA), since most Brazilian and international studies are limited to applications in non-structural concrete or mortars. However, since most of the CDW produced is classified as MRA, studies are needed to analyze its properties for structural purposes, especially the durability aspect. Thus, the general objective of the work is to evaluate the durability of concrete produced with coarse mixed recycled aggregate (MRA_c) when exposed to chloride ions. Concretes were produced with three different dosages, using the method proposed by ABCP, varying the percentage of replacement of the coarse natural aggregate (NA_c) by MRA_c (20% and 50%) and adopting, in all mixtures, the replacement of 20% of the CP V – ARI cement by the mineral addition metakaolin (MK). In the fresh state, the performance was evaluated through the slump test and the specific mass test. The analysis of the properties in the hardened state was carried out through the compressive strength tests, as well as physical indexes of the concretes, such as water absorption, void index and specific mass. To analyze the durability, the chloride content was determined in test specimens cured in the laboratory, as well as in samples exposed to the action of the environment, positioned at different distances in relation to the sea (199 m and 881 m). Regarding the use of MRA_c, the compressive strength results tended to decrease compared to conventional concretes, although this reduction was smaller in concretes using 20% MRA_c and greater in those using 50% MRA_c. The use of MK improved the compressive strength results in these concretes, allowing them to have values closer to conventional concrete. Regarding the property of water absorption by capillarity, concretes using MRA_c absorbed more water compared to conventional concrete, which was already expected due to the high porosity of these materials. The use of MK improved this property in all concretes, due to the high content of fines in this supplementary material. Regarding the influence of the type of curing in the concretes, it was found that the averages of the compressive strength results are statistically equal and the sample averages of the results of water absorption by capillarity are equal, demonstrating that the type of curing did not influence the results in the hardened state of the concretes. Regarding the chloride penetration results, all concretes analyzed (conventional, 20% and 50% MRA_c) presented values within the normative limit and the use of MK did not significantly influence the results; this was also observed in relation to the “distance from the coast” factor, whose average results were statistically equal, showing that this factor did not influence the results. Regarding the isolated effect of chloride penetration on the compressive strength of concretes, statistically, the average results were equal.

The objective of this work is to conduct a transient analysis of heat transfer in vertical oil wells, proposing a mathematical model to predict transient temperature fields in these structures. Traditionally, the most widely used strategy for modeling thermal phenomena in wells is the pseudo-steady-state approach, which assumes steady state heat transfer in the wellbore. However, this simplification may lead to significant errors, particularly under dynamic conditions or during the initial stages of operation. In such scenarios, accounting for transient heat transfer can improve prediction accuracy. To address this, this study develops a mathematical model for transient heat transfer in vertical wells, incorporating frequently neglected mechanisms such as radiation in annuli and convection at the well surface. The methodology comprises four main steps: a) a literature review on thermal modeling in oil wells; b) development of a mathematical model to predict temperature profiles in oil wells, based on mass, momentum, and energy conservation equations; c) proposal of a numerical strategy to solve the aforementioned mathematical model; and d) application of the model to determine temperature distributions in oil wells, comparing results with field data and existing literature models, as well as conducting parametric studies. Results demonstrated that the model aligns well with sensor data from an onshore well and other literature models, with errors typically below 5%. Parametric studies further highlighted that radiation significantly impacts annuli filled with gases, while surface convection is critical for predicting well cooling during shut-in operations. The model exhibited higher accuracy in dynamic scenarios, such as well start-ups and shut-ins, outperforming the pseudo-steady-state approach. This study advances the understanding of transient thermal e!ects in oil wells, emphasizing the influence of mechanisms like annular radiation and surface convection. Its application may enhance the analysis of oil well integrity under dynamic operational conditions.

The objective of this work is to develop a methodology to model the cycling times of the intermittent gas lift (IGL) method in onshore oil wells, using cycle adjustment data and applying methods that optimize gas injection in the artificial lift system. The approach aims to maintain or increase the oil recovery factor while meeting the mechanical strength criteria of the involved structures. Data-driven models have been widely employed across various engineering fields, especially in the oil and gas industry, where increasing operational complexity has driven the demand for more advanced technological solutions. The methodology proposed in this work is intended to support the decision-making process in the modeling of cycling times, contributing to the reduction of the need for manual interventions by well operators and to the improvement of the structural integrity management of production facilities. The results obtained demonstrated that the developed model is capable of accurately predicting the optimal cycling times. Moreover, a significant reduction in the operational variability of the cycles was observed, which favors production stability and the efficient use of injected gas. These results indicate that the methodology represents a viable, effective, and sustainable alternative to enhance the reliability and efficiency of onshore production systems.

With increased operating time and exposure to environmental conditions, many bridges have suffered from the appearance of pathological manifestations, which emphasizes the importance of carrying out periodic inspections and maintenance to guarantee structural safety. In this context, the adoption of sustainable practices and advanced technologies helps in the early identification of structural problems, which results in a reduction in repair and maintenance costs. Structural Health Monitoring (SHM) makes it possible to continuously monitor and evaluate the behavior and condition of structures, helping to make decisions regarding the need for maintenance and repair. Most traditional SHM methods require the application of sensors directly to the structure to obtain information on structural performance, where, in certain cases, due to the costs involved and the environmental conditions, the application of these techniques becomes unfeasible. Thus, the use of satellite images has emerged as a suitable alternative to traditional SHM, making it possible to measure displacements in and around the structure over time, without the need for direct contact. This study aims to apply and evaluate the Multitemporal Synthetic Aperture Radar Interferometry (MTInSAR) method as a tool to support the process of inspecting and monitoring displacements in bridges. To this end, displacements were extracted from the bridge over the São Francisco River, which joins the municipalities of Propriá in the state of Sergipe and Porto Real do Colégio in the state of Alagoas, and from the São Francisco Bridge, located in the city of São Luís, in the state of Maranhão. The set of images used was acquired by the Sentinel-1A mission. The results showed promises for using the method as a tool to support bridge inspection and management. The displacements obtained indicate that the two bridges show little movement, with no signs of structural damage. However, when analyzing the displacements around the São Francisco Bridge, signs of subsidence were observed near one of the bridge abutments, alerting us to the need for a detailed geotechnical investigation. Furthermore, when evaluating the inspection and management flowchart for Special Structures (SSOs) presented by NBR 9452 (ABNT, 2023a), a proposal was made to incorporate satellite monitoring as a tool for obtaining preliminary information on the structure and its surroundings, helping to target inspections more efficiently.

Fibers are known to improve the performance of concrete in post-cracking behavior,
particularly in terms of mechanical properties such as tensile strength, flexural capacity, and
toughness. The stress transfer bridging effect of the steel fibers and the confinement caused by
them alter the moment redistribution in the frames. In this context, this study aims to
contribute to the design of steel fiber-reinforced concrete (SFRC) frames based on numerical
analysis by applying the ABNT NBR 16935 (2021). The constitutive relationship of SFRC is
made by means of the plastic damage model Concrete Damaged Plasticity (CDP), when a
nonlinear behavior of the composite is adopted. To validate the applicability of the model, a
numerical validation was performed, reproducing in ABAQUS the beams and frames tested
experimentally. Initially, the numerical validation was carried out by simulating the SFRC
beams tested experimentally by Conforti et al. (2018) and Buttignol et al. (2017). Next, the
reinforced concrete frames tested experimentally by Cranston (1965) and Li et al. (2022) were
simulated. Subsequently, the same frames were analyzed with the addition of steel fibers.
Finally, reinforced concrete and SFRC columns subjected to centric and eccentric
compression were analyzed numerically. In general, the numerical results indicate a good
correlation with the experimental results, thus validating the methodology proposed in this
work. In the SFRC frames, the steel fibers increased the stiffness of the beam-column joint,
leading to a change in the moment redistribution. The SFRC frame nodes began to resist a
higher bending moment, and with a smaller rotation, compared to the reinforced concrete
frame. The addition of steel fibers also allowed for the reduction of longitudinal
reinforcement in the beam and improved the performance of the column, especially regarding
tensile forces. However, the addition of fibers did not increase the load capacity and ductility
of the columns. Regarding the shear behavior of the beams, for the two volumes of fibers
studied, the possibility of partially or totally replacing the transverse reinforcement was
confirmed. The importance of using a minimum amount of flexural reinforcement in SFRC
beams was also highlighted, even though the ABNT NBR 16935 (2021) allows the total
replacement of conventional reinforcement.

The use of fiber reinforced concrete (FRC) for structural purposes has been gradually increasing
and this growth has resulted in the emergence of several standards. As far as Brazil is concerned,
although FRC has been used in construction over the last 15 years, the first standard related to
the design of FRC structures was only published in 2021. This standard represents the
calculation aspects that must be considered when designing FRC structural elements, however,
the design steps are not fully illustrated. Based on this issue, this work aims to establish
calculation aspects for the flexural design of fluid concrete beams partially reinforced with
fibers (FCRF) and fluid concrete beams high strength partially reinforced with
fibers (FCHSRF). For this purpose, a numerical study was carried out using the finite element
method of FCRF beams and FCHSRF beams, and through concepts of damage mechanics and
constitutive relations, the beams were analyzed for situations of section reinforced with fibers
and reinforcement and of section reinforced only with fibers. Thus, a flexural dimensioning
guide for FRC beams was established, considering that the central hypothesis of this guide is
based on the possible failure mode of the structure. Based on this, and with the aim of evaluating
this methodology, a comparative study of the results from the guide proposed in this work was
carried out in relation to some FRC standards. Thus, for the section reinforced with fibers and
reinforcement, it was found that the largest dispersion verified is around 16%, and the result by
the fib Model Code 2020 (FIB, 2024) and by NBR 16935 (ABNT, 2021) result in lower values
and the one established by ACI 544.8R (ACI, 2016) results in a higher value, when compared
to the proposed guide. And for the section reinforced only with fibers, the largest variation
observed between the proposed guide and the regulations was around 2% and it was observed
that the behavior of the variations is similar to the previous analysis. Therefore, despite the
differences in the hypotheses of the methodologies, the variations observed in this analysis were
much smaller and the results similar, which shows the potential of this work to contribute to the
establishment of the design aspects of fiber reinforced beams.

Masonry is one of the oldest construction techniques in humanity. Despite millenia of study and improvement, there are still gaps in scientific knowledge and disadvantages to overcome. This is partially due to the difficulty in modelling and characterizing the material, that presents heterogeneous and periodic characteristics. One way to improve masonry about some of its weaknesses is fiber reinforcement. Fiber-reinforced Cementitious Matrix (FRCM) is a kind of reinforcement that has been well studied in this context. Consists of the coating of one or both faces of a masonry wall with a mesh of fibers embedded in cementitious matrix. Several materials can be used as fibers, the most common being steel, carbon, glass and aramid. The use of natural fibers (NFRCM) presents potential advantages in the scope of sustainability, but it is still little explored. Among the natural fibers, sisal fiber stands out, which is used in the form of ropes and presents abundant production in Brazil. However, FRCM presents an even greater challenge of modelling, since it increases the complexity and number of phases of masonry. The Finite-Volume Direct Averaging Micromechanics (FVDAM) technique is a promising option and still without application in the context of natural fibers. It consists of a homogenization technique that uses the Finite-Volume Theory (FVT) to calculate the effective properties of a heterogeneous material. Thus, the objective of this work is to investigate the effectiveness of FVDAM in the modelling and homogenization of masonry reinforced by NFRCM, comparing the results with other modelling techniques and physical tests.

In offshore oil exploration, the construction of a well requires long and complex operations,
which results in high costs, mainly related to the rental of drilling rigs. it is essential to
analyze the sequence of operations required for its construction, particularly concerning its
structure, given its importance throughout the well's lifecycle, in order to seek a reduction in
errors and execution time. A promising analytical approach is to use historical data in the
planning of new offshore operations, aiming to bring more predictability to the assessment
and design process of new wells. To do so, operational sequence models of the well structure
were developed based on actual drilling schedules to establish parameters for duration and
anomalies for production, injection, and special wells. The analyses were conducted using a
database of drilling schedules carried out by an oil company. The schedules were imported
into spreadsheets, where they are grouped according to well type, and specific well structure
activities are separated from others to establish the operational sequence and its parameters.
The developed models can be used for both the design of new wells and the evaluation of previously executed schedules, aiming to reduce errors, downtime of equipment and personnel, and, consequently, cost reduction.

In the design of reinforced concrete structures, the analysis of shear strength is an essential step to ensure the safety and durability of the structure. Although most of the technical standards, such as NBR 6118 (2023), provide models for evaluation of the shear strength of rectangular cross-sections, specific guidelines for the cases of circular cross-sections, widely used in engineering applications, in general, are not reported. To overcome this gap, some international codes and standards use simplified methods based on those developed for rectangular cross-sections, introducing adequacy parameters to define fictitious dimensions, such as, effective depth h and the width bw. Different theoretical approaches and experimental works are available in the literature aiming to evaluate the individual contributions of concrete and transversal reinforcements to the shear strength of elements with circular cross-sections. However, a consensual conclusion on the best model for evaluating such contributions does not exist yet. In this context, the present work aimed to analyze the performance of existing models for predicting the shear strength of reinforced concrete elements with solid and hollow circular cross-sections, subjected to simple bending and flexo-compression. Additionally, the performance of both circular and spiral stirrups for such cross-sections was also assessed. For this end, a bibliographical review of existing prediction models was carried out, followed by the construction of a large database from 291 tested specimens available in the literature, for comparative analysis between theoretical and experimental values. Electronic spreadsheets were used to automate the calculations of the selected models. A descriptive statistical analysis was conducted, covering measures of central tendency, variability, and error metrics. Graphic representations, such as box plots and radar charts, were employed for result visualization. Normality and hypothesis tests were applied to evaluate the statistical significance and adequacy of the models to the experimental data. Based on the statistical analyses, it is observed that, in general, the theoretical results presented non-negligible discrepancies in relation to the experimental data, although the predictions of some models showed good adherence in relation to the experimental results. Also, it is worth noting that, even though most of the models exhibited conservative results, some of them provided unsafe shear strength values. In summary, there is a need to carry out more theoretical and experimental studies aiming at a more accurate representation of the shear strength behavior of circular reinforced concrete sections, improving the design guidelines for those structural elements and contributing to scientific and practical discussions in the corresponding field of knowledge.

The imperative transition to renewable energy sources, driven by the need to address energy security and climate change challenges, underscores the pivotal role of offshore wind energy. This study delves into the multifaceted aspects of wind energy, examining both the potential in shallow water installations and the ongoing paradigm shift towards larger turbine sizes. In the exploration of shallow water regions, economically viable locations for wind farms emerge between 50 and 70 meters in depth, employing shared anchor concepts and mooring line systems. The selection of an optimal system type is critical, and past research highlights the efficiency of synthetic fiber ropes over traditional chain catenary configurations. This paper presents dynamic analyses applied to a 15 MW turbine and the VolturnUS-S reference platform in the Celtic Sea. A comprehensive comparative assessment of planar displacements, rotations, and loads on a shared anchor is conducted using nylon and polyester ropes. Results show a notable 44% reduction in peak resolved anchor load with nylon compared to polyester, albeit with larger displacements and rotations, suggesting potential improvements in mooring design. With nylon being 10% more cost-effective than polyester and ongoing investigations into efficient anchor concepts, this study encourages further exploration of nylon applications in shallow-water wind farms. Simultaneously, the wind energy sector grapples with the challenge of escalating turbine sizes to reduce the levelized cost of energy. This necessitates smaller platform and mooring systems, especially in the context of shallow-water installations. Building upon prior research, which employed a multi-objective optimization (MO) framework for designing platforms and mooring systems with synthetic lines, this study extends the existing framework by incorporating computational efficiency strategies. The utilization of a static methodology and a running metric as a termination criteria for the MO contributes to computational efficiency. Additionally, the study explores the optimization of an alternative mooring system using spring polymer, revealing the potential for a substantial reduction in mooring system costs for smaller radii. This holistic approach addresses the dual challenge of enhancing turbine efficiency in larger sizes while adapting to the constraints posed by shallow-water installations. The fusion of insights from both aspects contributes to a more comprehensive understanding of the evolving landscape of offshore wind energy.

The pursuit of better understanding and description of structures is of fundamental importance in the field of structural engineering. For an accurate description, it is necessary for models to consider the physical nonlinear behaviour of materials. The main theories that account for nonlinear effects are plasticity theory, fracture mechanics, damage mechanics, and phase field models. These theories have significantly contributed to structural engineering; however, they also face limitations associated with nonlinear solutions, such as describing post-peak nonlinear behaviour or presenting infinite solutions when addressing the problem of strain localization. Lumped Damage Mechanics (LDM), initially proposed for frame elements and later formulated for two-dimensional media, has proven capable of performing nonlinear analyses while avoiding the strain localization issue without the need for any regularization techniques. Therefore, the present study aims to contribute to the development of analyses using LDM by proposing new models for the analysis of plates, slabs, and thin shells. The study selected the Discrete Kirchhoff Triangle (DKT) finite element for plate analysis and the Constant Moment Triangle (CMT) for the analysis of plates, slabs, and shells. For the latter, the Constant Strain Triangle (CST) element was also employed. All elements were reformulated to modify their kinematic variables and allow the inclusion of LDM considerations. For plate elements, a nonlinear damage evolution law with exponential softening behaviour was adopted. This study also developed an experimental campaign involving the casting of fibre-reinforced concrete plates. The plate finite elements were applied to a series of experimental tests found in the literature as well as the experimental tests conducted in this study, yielding satisfactory results in terms of Force vs. Displacement, crack distribution, and crack opening displacement. Based on the plate element using the CMT, this study proposes a new model for evaluating reinforced concrete plates (slabs). In this model, the inelastic variables are defined as damage and plastic rotations, which can be related to the reinforced concrete response (cracking and reinforcement yielding). Different damage evolution and plastic rotation laws are proposed. The model was applied to a series of experimental tests from the literature, with results showing high accuracy compared to experimental data in terms of Force vs. Displacement and the initiation and propagation of complex networks of cracks. Finally, a flat shell model for application to reinforced concrete shells is proposed. Axial effects are described by the CST finite element, assumed to have an elastic-linear response, while bending effects are modelled using the proposed slab element. The model was applied to a couple experimental examples from the literature, achieving results with good accuracy, proving suitable for predicting Force vs. Displacement responses and the cracking condition, in comparison to an arch model and experimental results.

Currently, more sustainable alternatives have been sought within the civil construction sector, as a way of reducing harmful interference to the environment. Among these alternatives, the use of recycled concrete aggregates stands out for the production of mortars and concrete, with or without a structural function. However, the use of these aggregates is a subject that still needs to be studied, in the sense of seeking alternatives that aim to understand the porosity present in recycled aggregates, considered as the main obstacle to its use for structural purposes. Thus, the main objective of this study is to evaluate the contribution of recycled concrete aggregate (ARC) dosages on the properties of structural concrete in fresh and hardened states. Concretes with different dosages were produced, using the method proposed by ABCP, varying the percentage of replacement of natural aggregate by recycled in 25%, 50%, 75% and 100%, as well as varying the size of the ARCO (fine and coarse). Fresh state performance was evaluated using the slump test. The evaluation of properties in the hardened state was carried out using the compressive strength test, modulus of elasticity and physical indices of concrete, such as water absorption, voids index and actual specific mass. From the results of the consistency test, voids index, and absorption, all mixtures showed high values. With regard to the compressive strength results at 28 days, the mixes produced with 100% ARCO replacing only the fine aggregate, showed a result of 21.21 MPa; for the mixtures replacing only the coarse recycled aggregate, up to 75% replacement, satisfactory results were found in terms of compressive strength, with a value of 20.98 MPa being obtained for the referred percentage. For replacements of both (fine and coarse), the replacement limit was between 50% and 75%, with values of 25.60 MPa and 19.74 MPa, respectively. In this way, the interference of the size of the aggregate in the properties of concrete is evident, both in the fresh state and in the hardened state. This can be justified by the granulometry of the aggregate, which interferes with the filling of voids in the concrete, favoring greater compaction and locking of the particles; in addition to the effect of the porosity of the recycled aggregate, which is more evident in the coarse aggregate, due to the particle size. This higher porosity of the coarse recycled aggregate also influenced the results of modulus of elasticity, since this property determines the stiffness of the aggregate which, in turn, controls the ability of the aggregate to restrict matrix deformation. Complementarily, the results demonstrated the potential use of ARCO, with the possibility of replacing the natural aggregate in large part, as opposed to the current standard, which limits the percentage of replacement to up to 20% in applications for structural purposes (resistance class of C20), without bringing a clear indication if this replacement refers to fine aggregate, coarse aggregate or both.

Aiming to develop a comparative evaluation of the principles for load analysis in bridges, this work proposes to perform the structural verification of a special work of art - OAE, through the study of the mobile loads adopted by the Brazilian (NBR 7188:2013), American (AASHTO: 2002 and 2020) and European (Eurocode 1: 2003) standards. The verification of the loads, generated by means of the mobile loads described in the respective standards, was performed on the Croatá river bridge, located on BR-423/AL, in the municipality of Canapi/AL, observing the limits of weight and dimensions, related to cargo vehicles on Brazilian highways, established by the resolutions of the National Traffic Council - CONTRAN. The bridge design information was made available by DNIT/AL, enabling the evaluation of the applied loads generated by the design loads described in the referred standards and by a special freight train. Numerical modeling was employed, through the finite element method (FEM), to analyze the effects of the passage of the standard trains, determining the maximum loads generated in the superstructure with the passage of the standard trains, comparing them and applying the determinations established in the standards. Using the internal forces from the numerical analysis, the methodology established by DNIT was applied to the results obtained in order to elaborate the Special Transit Authorizations - STA, which establishes the criteria for verifying structural safety in highway bridges. Through this study, it was concluded that the OAE under discussion is in adequate structural conditions for the passage of special loads and loads from international standards, whose safety factors presented in the verifications are higher than the unit. It was also concluded that the Brazilian standards, in contrast with the international standards, presented in the case analyzed higher safety factor values during the structural verification.

Determining the structural system of a building involves defining materials and arranging
elements in order to efficiently resist combinations of actions. In cases where steel or composite
rigid frames become inefficient, due to the high dimensions of the profiles or the difficulty and
cost of rigid connections; and bracings cause considerable impact to architecture due to the
obstruction of facades or circulation areas; shear walls systems are a viable alternative lateral
resisting system. However, in these buildings, the shear walls positioning and the layout in
the plan is most responsible for the torsional effects. In order to design a shear walls layout that
minimizes these effects, is compatible with the architectural plan, and satisfies the
requirements of the economy, strength, and rigidity, the designer performs an iterative and inefficient
process of trial and error, whose improvement of the solutions is dependent on previous projects
experience and intuition. To evaluate the use of a genetic algorithm in the conceptual design
of shear walls layout, a computational program was implemented that minimizes the structural
weight as a function of the layout, with restrictions to the resistant capacity, displacement, to
the effect of torsion, and the need for openings for the movement of people. The comparative
analysis carried out between four optimized models and a reference model, adapted from a real
the project resulted in a considerable reduction in the consumption of concrete, formwork, and steel
reinforcement; evidencing the benefits of introducing the optimal design process through the
genetic algorithm.

The finite-volume theory is an equilibrium-based approach and has been successfully employed in solid mechanics analysis due to the equilibrium equations' local satisfaction and the imposition of continuity conditions in a surface-averaged sense through the subvolume interfaces. Previous investigations include stress and displacement fields convergence and computational cost, showing the approach's efficiency, especially in heterogeneous materials and structures. However, those investigations did not include an energy analysis, which is especially important in compliance minimization problems. As the finite element method, energy-based approaches impose energy balance, which guarantees a monotonic energy convergence. The first idea of this contribution is to address a numerical investigation about the main mechanical energy aspects involving the generalized finite-volume theory for continuum elastic structures in quasi-static analyzes. The obtained results are verified with analytical and finite element-based analyzes, showing a monotonic energy convergence for the three versions of the finite-volume theory and the energy balance's satisfaction for the higher-order versions when a sufficiently refined mesh is employed. Topology optimization is a well-suited method to establish the best material distribution inside an analysis domain. It is common to observe some numerical instabilities in its gradient-based version, such as the checkerboard pattern, mesh dependence, and local minima. This research demonstrates the finite-volume theory's checkerboard-free property by performing topology optimization algorithms without filtering techniques and employing elastic and elastoplastic formulations. The formation of checkerboard regions is directly associated with discretized domains connected by nodes, usually observed in topology optimization techniques based on the finite element method. On the other hand, the finite-volume theory satisfies the continuity conditions between common faces of adjacent subvolumes, which is more likely from the continuum mechanics point of view. An incremental elastoplastic formulation of the standard finite-volume theory is performed to verify how the plastic strain could interfere with the optimized topologies and reduce their stress concentration. The topology optimization algorithms based on the finite-volume theory are also performed using a mesh independent filter that regularizes the subvolume sensitivities, providing optimized topologies that avoid the mesh dependence and length scale issues. The solid isotropic material with penalization (SIMP) approach is employed to avoid discrete optimization problems. The proposed optimization problem has shown to be efficient, avoiding numerical instabilities, such as checkerboard pattern, mesh dependence, and length scale issues.

Safety in the transportation of hydrocarbons and other fluids in pipelines is one of the topics of
greater attention in the oil and gas industry. Recently, this industry has had great
concerns about how the Vortex-Induced Vibration (VIV) phenomenon affects life
fatigue of submarine pipelines and components, especially free-range pipelines. Worldwide,
there are several of these structures installed that have reached the end or half of their design life,
which makes it imperative to revisit the initial predictions and assess the need for intervention in the
to extend their useful life, especially with regard to VIV. These and other
analyzes are based on the correct representation of the pipeline's on-site behavior. The method of
Finite elements are widely used in modeling this behavior. However,
this is not a trivial task, since it depends on the use of various software for stages
intermediate. In addition, these analyzes involve handling large amounts of
data related to the bathymetry of the seabed and material properties, geometry
duct, current, among others. In this way, this whole process is usually time consuming and
prone to errors. At the same time, the oil and gas industry has undergone a transformation
in recent years. This scenario brought opportunities for the development of
new tools for the day-to-day of the professional responsible for these analyzes. This job
presents the development and structure of a computational with functionalities from pre to
post-processing of analysis data aimed at improving the flow of fatigue analysis in
submarine pipelines subject to free spans.

Currently, the most diverse oil deposits are discovered in increasingly challenging environments for existing technologies. Thus, the constant development of research and technologies to support the various areas of petroleum engineering is important. The well engineering, which is responsible for designing its structure and trajectory, stands out in this work. Drilling string failure is a very costly event for the oil and gas industry, as it is necessary to stop the entire operation, which results in non-productive time. Therefore, several studies are carried out in order to predict problems during drilling. Torque, tension, compression and bending can be correctly predicted for known well geometries, but unwanted changes in well geometry during the drilling process can result in errors and uncertainties in predicting the stress state. It is proposed to predict these uncertainties in the trajectory by the statistical analysis of previously executed wells and categorized according to their correlations with each other. Performing the data analysis enables the construction of the fictitious trajectory which will be used to predict the additional forces to the loads acting on the drill string induced by the trajectory deviation.

 The design of civil construction structures is commonly associated to three general steps:
structural conception, sizing, and analysis and verication. It is an approach highly dependent
on the experience and creativity of the designer, and is tied to an trial and error
strategy. This work aims to formulate and to implement computational models based
on topology optimization to assist on the denition of initial structural conception of
cable-based structures. The mathematical formulation proposed in this work incorporates
multiple load cases, nodal cost and a constitutive model of cables with limit resistance.
The results show that topology optimization tools can be used to suggest initial structural
conception, assisted by a mathematical method, and with the potential of break the pattern
of traditional topologies, unlocking designer's creativity. However, structural systems based
solely on cables are rare, and therefore for the features presented in this work to have a
direct application in industry, there is still the need to evolve the formulation presented
here, also incorporating elements resistant to compression actions.

Este trabalho busca contribuir no campo de pesquisa de identificação de danos em vigas com base nas propriedades modais, propondo estudos de sensibilidade em dois modelos numéricos, que serão elaborados em software comercial de elementos finitos, a saber: uma viga biapoiada de concreto simples e uma viga biengastada de aço, para avaliar a fiabilidade de quatro métodos de identificação de dano único e dano múltiplo: (1) Diferença da Curvatura Modal, (2) Indicador Baseado em Dados dos Modos de Vibração, (3) Mudança da Energia de Deformação Modal e (4) Mudança da Energia de Deformação Modal Reformulada, propondo-se ainda a modificação dos dois primeiros métodos. Os resultados obtidos mostraram que o método Mudança da Energia de Deformação Modal, apesar da dificuldade existente quanto à aplicação prática na engenharia, identificou os danos corretamente, o método Mudança da Energia de Deformação Modal Reformulada se mostrou promissor e os métodos modificados
propostos apresentaram melhor desempenho em relação aos originais.

A possibilidade de se trabalhar com materiais mais resistentes permite conceber estruturas mais esbeltas e leves que, por sua vez, podem ser mais sensíveis à ação das cargas dinâmicas oriundas do movimento de pessoas, máquinas ou ações da natureza, como o vento. O surgimento e propagação de fissuras, acréscimos de tensão devido a deslocamentos excessivos bem como desconforto aos usuários do empreendimento devido às acelerações que surgem na estrutura são alguns dos problemas estruturais que envolvem a dinâmica. Outra adversidade está relacionada com equipamentos sensíveis instalados em pisos, em que, ao estarem submetidos à determinada (indevida) aceleração, podem sofrer danos. As abordagens mais comumente empregadas para controle dessas vibrações excessivas é o enrijecimento da estrutura, porém em muitos casos este tipo de abordagem é inviabilizada por restrições arquitetônicas, estéticas ou relativa à própria capacidade da estrutura ao sofrer o acréscimo de elementos estruturais pesados para o enrijecimento. Problemas de vibrações em lajes não são incomuns; lajes industriais, por exemplo, estão sujeitas a vários tipos de ações dinâmicas simultâneas provenientes das diversas máquinas em operação instaladas no piso da fábrica. Outro caso são as lajes de academias, salões de festas e outros ambientes com grande movimento de pessoas que geram acelerações no piso. O presente trabalho explora a adoção de sistemas mecânicos de controle de vibrações (amortecedores) acoplados às estruturas, especificamente em vigas e placas, como uma solução alternativa à resolução do problema de engenharia. Utilizam-se ainda técnicas de otimização com o objetivo de obter projetos com a melhor relação custo-benefício de amortecedores. Dessa forma, realiza-se uma modelagem numérica via implementações computacionais do problema de vibração e seu controle em vigas e placas, com os resultados são validados e comparados com exemplos da literatura. Notou-se que, com o processo de otimização, pode-se chegar com a mesma eficiência na resposta estrutural, que utiliza massa e taxa de amortecimento menores.

A maior parte das reservas petrolíferas brasileiras se encontra em ambientes marinhos, que
apresentam vários fatores que dificultam sua produção, como lâminas d’águas elevadas, interação
fluido-estrutura e batimetrias irregulares. Nesses ambientes offshore, os dutos são estruturas
eficientes para o transporte de fluidos entre plataformas, entre o poço e a plataforma e entre a
plataforma e um local em terra, sendo utilizados há bastante tempo em larga escala na indústria
petrolífera. Os dutos suspensos recebem o nome de risers e os apoiados no solo de dutos
submarinos, pipelines e flowlines. Os dutos são dimensionados de acordo com o tipo de atividade
que irão desempenhar e a hidrodinâmica do problema.
Considerando as irregularidades do solo marinho, os dutos apoiados podem apresentar trechos
com vãos livres, que devem ser considerados no projeto de forma a evitar problemas de segurança
estrutural por excesso de deformações. As estruturas estão submetidas a diversas formas de
carregamentos, normalmente agrupados nos referenciais normativos, como: cargas permanentes,
cargas variáveis (acidentais) e cargas excepcionais. Como as ações ambientais variam de
intensidade de forma significativa ao longo da vida útil da estrutura, elas são classificadas como
cargas variáveis e exercem uma grande influência para a análise do comportamento de dutos,
pois ocasionam carregamentos cíclicos. Dentre os carregamentos ambientais, encontramos: as
cargas do vento, da corrente, da onda, das marés, entre outros.
O carregamento combinado de onda e corrente em dutos em vãos livres dá origem às vibrações
induzidas por vórtices (VIV), objeto de estudo de várias áreas da engenharia, sendo um dos
principais desafios em projetos offshore. Essas vibrações causam tensões e deformações periódicas,
podendo levar à falha da estrutura por fadiga. Para evitar que ocorra esse problema, as
oscilações devem ser minimizadas, estando as frequências de vibrações dos vórtices com valores
distantes dos valores das vibrações naturais da estrutura. Esta frequência natural depende de
parâmetros como a rigidez, o comprimento do vão livre, a massa do duto, incluindo a massa do
fluido interno e a massa adicional.
O presente trabalho se concentra em fazer um estudo do problema de dutos em vãos livres submetidos
à VIV. Um estudo paramétrico foi realizado para obter os fatores que mais influenciam
na vida à fadiga da estrutura, por meio da técnica de Planejamento e Análise de Experimentos
(DOE), utilizando o software Isight. Análises estática e modal foram elaboradas no Abaqus,
tendo como resultados principais as frequências naturais da estrutura do duto. Por fim, o estudo
de vida à fadiga foi realizado, de acordo com a recomendação prática DNVGL-RP-F105, por
meio da planilha FatFree.

A análise de danos em estruturas é um tema de pesquisa muito importante para diversos campos
da engenharia, capaz de fornecer informações relevantes frente à sua integridade estrutural,
norteando as decisões relacionadas às ações de intervenção. Diante da necessidade e importância
do tema, diversos estudos vêm sendo desenvolvidos com o intuito de conceber técnicas, para
auxiliar na quantificação do dano por meio de procedimentos técnicos que envolvam atividades
laboratoriais. É exatamente nesse aspecto que o presente trabalho se insere. Nesta pesquisa, é
estudada a aplicação de uma técnica óptica-numérica, a Correlação de Imagens Digitais (CID),
como suporte à aquisição de informações para análise quantitativa de danos, na qual se buscará
analisar a integridade estrutural de elementos de concreto por meio da perda de rigidez à flexão.
Para a quantificação do dano, as informações obtidas pela CID, por meio de um software de
código aberto, o ITOM, são comparadas com métodos tradicionais de aquisição, como LVDT’s
(Transdutores de Deslocamento Linear). Para avaliação da perda de rigidez, foram analisadas oito
vigas, através do ensaio de flexão, fornecendo assim um ambiente controlado para o emprego
desse ensaio não destrutivo. Diante dos resultados obtidos, foi possível verificar o potencial da
CID, por meio do ITOM, que, mesmo em fase de desenvolvimento e aprimoramento, mostrou-se
capaz de quantificar aberturas de fissuras diretamente em imagens e gerar deslocamentos e
deformações nodais para construção de mapas de cores, dando suporte para análises de estruturas
em Estado Limite Último (ELU) e de Serviço (ELS).

The design of an oil well is a complex and multidisciplinary activity, which has as a
of its main premises the adequate prediction of well integrity throughout its life cycle.
life. Despite all the care taken in the design of its structure, eventually the same
may be exposed to an unforeseen loading condition. With regard to monitoring
of wells in service, the acquisition of data referring to variables such as pressure and temperature
allows to identify if the well is operating within the parameters foreseen in the project. Through
of time series forecasting techniques, the information from these sensors has
potential to be used not only to diagnose a problem that has already occurred, but also
to prevent its occurrence, creating a supervisory system in real time that is capable of
anticipate future loading states. However, in the context of well projects, with
the evolution of coating design standards, the use of probabilistic methods is suggested
in its dimensioning, highlighting the importance of a better knowledge about the
design variables. Statistical inference about manufacturing data is driven by demand
for a better understanding of the uncertainties about these parameters, in terms of the dimensions
of the tubular and the properties of the metallic alloy that constitutes it. This dissertation is about
a set of statistical inference and data prediction techniques, as support for practices
modern design and structural integrity monitoring of wells.