Based on the urbanization of regions close to federal highways, the National Department of Transport Infrastructure (DNIT) published, through the Transport Research Institute (IPR), the typical project album for mixed walkways. The IPR-748 publication, which presents the projects, aims to speed up the contracting and construction of these structures, bringing safety and comfort to highway users. In the present work, these structures are analyzed from a dynamic point of view to estimate their natural frequencies, as well as the accelerations induced by pedestrians. Aiming to obtain the dynamic characteristics of these walkways, numerical models are developed using the ANSYS software to obtain the data, which will later be compared with the methodologies prescribed in NBR 7187:2021 and other international regulations that version on the subject. The study in question aims to qualify the dynamic performance of these structures, to certify compliance with Annex C of the aforementioned NBR and the absence of problems with excessive vibration and other discomfort to the user. As a result, it was observed that the proposed walkway presents a natural frequency in the resonant frequency spectrum and that problems related to excessive vibration may occur for certain load configurations of the structure.

It is believed that the use of fiber-reinforced concrete could be a solution to a recurring problem in Brazilian cities, which involves the need to replace cast iron drainage grates, which are frequently stolen, and reinforced concrete ones, due to failures, possibly because of their low mechanical performance resulting from impact loads. This study employs concepts of scientific dosage to produce ultra-high performance concretes and ultra-high performance rubberized concretes to assess the impact efficiency of this material compared to conventional concrete. Three types of concretes were used in this study, a conventional one, a UHPC, and a UHPFRC, which showed average compressive strength of 61.67, 128.76, 108.15 MPa, respectively. In addition, the concretes were subjected to the repeated drop weight test, with it being verified that UHPC and UHPFRC require seven times more drops than conventional concrete.

In 1296, under the design of one of the greatest architects of the time, Arnolfo di Cambio, construction began on the Cathedral Santa Maria del Fiore, which for many years was the largest church in Christianity. Built 55.00 meters above the ground, with an internal height of 32.00 m and an internal diameter of 45.40 meters erected on an octagonal plane, the Cathedral Dome is the largest ever built without the use of reinforcement. Weighing around 29,000 tons, the Dome of Santa Maria del Fiore is considered one of the greatest feats of engineering. The city of Florence is located between two seismic activity zones: Mugello, to the North, and Chianti, to the South. In May 2022, the city was hit by some earthquakes with a magnitude of up to 3.7Mw, same magnitude as events that occurred in June 2023. In September of the same year, seismic shocks with a maximum magnitude of 4.90 Mw were recorded and, in February 2024, seismic events of magnitude 3.5 Mw. To allow the perpetuation of historical constructions over the years, it is essential to analyze and predict the behavior of these structures, also including seismic action. Therefore, the present work aims to develop a non-linear numerical analysis of the seismic behavior of the Cathedral of Santa Maria del Fiore, using the finite element method evaluated in the ABAQUS computer program environment. The seismic analysis was developed with the help of the database made available by the SCALCONA 3.0 software from seven natural accelerograms, for five return times (50, 75, 101, 201, 475 years), of seismic events recorded in rocky outcrops that satisfy spectrum compatibility requirements with the regulatory response spectrum for any location within the Tuscany region. This analysis consisted of detailing accelerations, tensions and deformations resulting from the application of seismic events in the Cathedral's structure, as well as indicating the fault zones in the structure. The greatest stresses, accelerations and deformations were observed for the seismic event with a magnitude of 6.93 Mw, a distance from the epicenter of 83.53 km and a return time of 475 years. The static stress state varied from +1.80 MPa and -4.50 MPa to +2.31MPa and -8.50 MPa with the application of the event, with the highest acceleration of 40.84 m/s² and maximum horizontal deformation of 13.85 mm of the structure at the top of the vertical fissure on the southwest surface of the Dome. Therefore, a methodology for analyzing historic buildings subject to earthquakes was proposed through the construction of a numerical model calibrated based on experimental records of vibration modes and frequencies. The option to develop a model adjusted based on dynamic properties guarantees greater suitability since these parameters are much more sensitive to small and complex variations than static parameters, being specific and unique for each existing structure.

This work aims to experimentally evaluate the behavior of deep beams with geometric discontinuities, which have diamond-shaped notches and holes, not aligned and not geometrically symmetrical, in order to cause discontinuity in the ties and interrupt the formation of compression struts and strengthened to flexure and flexure/shear with Carbon Fiber Reinforced Polymers (CFRP), using the NSM-EBR hybrid technique. This strengthening technique consists of gluing and inserting laminates into openings made in the concrete cover layer, without reaching the existing reinforcement to avoid further damage to the structure, subsequently, FRP blankets are glued on the surface with grooves (external FRP application). The study also included the modification of the anchorage system of the reference wall beams, aiming to investigate new behaviors in structures with complex geometries and non-linearities. The variables considered in the study were the presence or absence of reinforcement in the web, the geometry of the wall beams, the presence or absence of anchorage in the bending reinforcement above the notch, the presence or absence of strengthening. Experimentally, the results obtained showed that the applied technique is efficient, resulting in an increase in the final load capacity of the strengthened beams in relation to the reference beams (Series 1). This increase was substantially more significant for beams with an opening, without reinforcement in the web and flexural/shear reinforced, with an average increase of about 182.75%. The average increase for beams with one opening, with web reinforcement and flexural reinforcement was 47.79%. For beams with two openings and without web reinforcement, the average increase was 36.14%, while for beams with two openings and with web reinforcement it was 30.81%.

Fluid-filled cylindrical shells are structures widely used in different engineering facilities such as oil rigs, nuclear power plants and storage tanks. In offshore structures, the action of ocean waves must be carefully evaluated, as the influence of fluid external to the outer walls of this structure can modify its dynamic behavior. This work presents an analytical-numerical approach to analyze the nonlinear vibrations of a cylindrical shell clamped, considering the presence of external and internal fluid with the inclusion of the effects of the movement of the free surface of the internal fluid. The strain fields and curvature changes of the mean surface of the cylindrical shell are described by the nonlinear Sanders-Koiter theory. The modal expansions, which describe the displacement fields of the clamped-free cylindrical shell, are obtained from the Chebyshev polynomials. The action of ocean waves is developed from Airy's wave theory and diffraction theory, where a parametric analysis is made to evaluate the influence of this charge on the dynamic behavior of cylindrical shells. Finally, the Rayleigh-Ritz method together with Hamilton's principle are used to discretize the nonlinear equations of motion of the system which, in turn, are linearized and solved to obtain the natural frequencies and vibration modes of the cylindrical shell with fluid-structure interaction. The results obtained are compared, when possible, with other studies found in the literature. In addition, a numerical analysis using the Finite Element Method using ANSYS commercial software is developed to evaluate the reliability and convergence of the analytical-numerical results obtained. The consideration of the external and internal fluid for analysis of free vibrations with application of hydrodynamic pressures is important, as it incorporates additional mass and reduces the values of natural frequencies. The influence of the free surface also alters the free vibrations of the cylindrical shell and, for large structures, a considerable effect is observed that cannot be disregarded. A nonlinear analysis of the dynamic behavior of the problem is also made, by obtaining the responses in time and phase plans, evaluating the dynamic nonlinear behavior of the cylindrical shells.

This work introduces an integrated methodology for thermomechanical analysis, applying
specific isoparametric finite elements for shells. These elements are developed through direct
isoparametric formulation, aimed at both flat and curved shell elements, and are based on the
theory of degenerated solids. The constitutive model used for these elements is based on the
von Mises plasticity equations, utilizing Mandel notation to facilitate the effective
implementation of tensorial constitutive equations. The developed formulations are detailed
extensively, aiming for deep understanding and applicability in future research. The validation
of the proposed finite element is conducted through four examples from the literature that have
analytical solutions. For the coupled thermomechanical approach, validation and comparison
are done with another four examples, of which two have analytical solutions and two are
modeled using the Abaqus software. TThe verification of the constitutive model is conducted
through four additional examples: the first two are based on literature results, while the last two
are modeled in the Amaru software. In all scenarios, the results demonstrate good agreement
with the analytical solutions and with the data obtained through finite element software.
Concluding, two case studies are presented. The first case involves a numerical simulation of
experimental results for temperature and stress in a pressure vessel, while the second is a
hypothetical simulation examining a section of a flare, considering the thermomechanical
effect combined with material nonlinearity (plasticity). This analysis includes the verification
of von Mises stress along the length of the structure, under different temperature levels.

Experimental tests were performed to investigate the flexural behavior of beams strengthened with the NSM technique, using steel bars and cement-based adhesive and CFRP laminates with epoxy-based resin. Nine beams were tested, one beam was used as reference, four beams were flexurally strengthened using different percentages of steel bars, and four beams were flexurally strengthened with varying rates of CFRP laminates. The experimental results show that both types of strengthening presented similar increases in strength. However, the beams strengthened with steel bars had a stiffer behavior, offering higher yield loads than those strengthened with CRFP. In addition, by raising the strengthening ratio, there was an increase in the strength and stiffness of the beam. Comparing the experimental results with the results estimated using the equations of ACI 440.2R (2017) and fib Bulletin 90 (2019), it can be concluded that both could estimate the failure mode and the ultimate load of the tested beans satisfactorily

This work proposes a method to analyze the design traffic load used in concrete bridges comparing it to real traffic based on uncertainty quantification and reliability structural. As a case study, the Brazilian and American design vehicles are used, and for such, it was considered the verification of the structural safety through the reliability index β. The analyses were applied to bridges with spans of 20, 30, and 40 meters, and the ultimate bending moments were studied. To represent the real traffic, a known database of vehicles was admitted, which makes use of the identification of heavy trucks according to the National Department of Transportation Infrastructure (DNIT), assuming that the bending moments induced by these vehicles follow the same probability density function of the respective weights. In addition to the analysis at time T=0 when the weighing was taken, verifications were also exposed for the extrapolated vehicle weights for a return period (T) of 15, 50, and 75 years. An extrapolation methodology and Monte Carlo simulations were used to obtain the extrapolated vehicle weights and the bending moments. The results indicate that the reliability indexes obtained are lower than the minimum required by international codes, thus encouraging better inspection practices regarding the weight of vehicles and the necessity for improvements of standards relating to traffic loads and/or bridges. Moreover, what it relates only to traffic loads, a higher percentage of the characteristic values of the live loads are exceeded in the unfavorable direction, if compared to recommended ABNT standard within the stipulated return period of 50 years

The growing demand for electrical energy in Brazil increases the need for cooling systems, which are responsible for a considerable portion of the electrical energy consumption in housing units (UH), whose reduction can be provided by the use of energy-efficient systems. As an option we have the sandwich panels, which, however, usually have metallic connectors that generate thermal bridges and can reduce performance. The use of Glass Fiber Reinforced Polymer (FRP) connectors is an alternative. The general aim is to compare the thermal performance of a building according to NBR 15575 (2021a; 2021b), verifying the impact of metallic and FRP connectors on the results. It was necessary to calculate the equivalent resistances following the methods of NBR 15220 (ABNT 2005; 2022) and ASHRAE (2016), of Parallel Flow and Isothermal Planes, in addition to a numerical simulation by Finite Element Method (FEM). Thermal performance was determined by the simplified method for all situations, in which all sandwich panels achieved the minimum level. Then, the computational simulation of a UH was carried out for Brazilian cities in the 8 bioclimatic zones, with variations of two types of absorptance and for all the equivalent resistance methods, totaling 144 simulations in the EnergyPlus software. The thermal performance level, the PHFT (percentage of hours of occupancy of the UH within the operating temperature range) and the CgTT (total annual thermal load for heating and cooling) were analyzed. Due to the PHFT, 80 simulations failed, and on the other occasions, it was not possible to establish a pattern of reduction or increase of CgTT linked to the type of connector. As contributions, it is reinforced that the PHFT and CgTB cannot be analyzed in isolation for design decision making, and that bioclimatic strategies are essential. A statistical treatment was also carried out to verify the significance of the variables absortance, method of equivalent resistance, and type of wall, on the indicators. The method for obtaining the resistance did not show significant results for any situation, the type of wall/connector was relevant in the level of thermal performance only, and the absortance showed significant influence on the results of CgTT and performance level. 

The civil construction industry requires each year the development of techniques and materials that provide satisfactory results, in shorter periods, with lower final production and maintenance costs. In addition, it is necessary that in its development there is a more sustainable look and focus on the environmental aspect. In this sense, the use of cements with calcined clay and superplasticizing additives provided several advances for the civil construction industry, enabling gains on the rheological behavior and mechanical properties. Cements with calcined clay provide environmental gains by reducing the clinker/cement ratio and improving the internal structure. However, its use is still restricted due to the difficulty in its application due to the high consumption of water in relation to a cement without additions. Thus, the search for superplasticizer additives based on polycarboxylates that act in cements with calcined clay has ample opportunity for investigation, providing cement-addition-additive systems that are increasingly compatible and efficient. Thus, this work seeks to characterize the interaction between three commercial superplasticizer additives based on polycarboxylate ether (PCE) and three cements (pure Portland cement CPV-ARI with calcined clay contents of 20% and 28%). The study began with the physical-chemical characterization of cements and calcined clay. The superplasticizer additives were characterized by determining the solid content, and via FTIR and FT-Raman measurements. The interaction between cement-addition-additive was verified with the determination of the optimum additive content by the Marsh cone and spreading by the mini-slump. The saturation content was used to assess the influence on mechanical strength; and kinetic and hydration mechanisms with a semi-adiabatic calorimeter. It was verified that the fluidity tests of cementitious matrix pastes using the Marsh cone and mini-slump are simple and fast, providing parameters for identifying the optimal levels of superplasticizer additives quickly and at low cost. The PCEs were found to be very sensitive to calcined clay, evidenced by the higher dosages of PCEs needed to achieve the same fluidity versus the clay-free system. At 28 days of hydration, cements with calcined clay together with PCEs additives have a greater increase in compressive strength compared to pure cements.

The conversion of solar energy into thermal energy through Concentrated Solar Energy (CSE) has become an alternative for the drying process of materials. Sugarcane bagasse, a residue of great impact on the Brazilian agroindustry, which can be easily used as biomass, has its use reduced due to its high moisture content, that is, low efficiency in energy production. This work aims to analyze experimental results, using solar concentrators built from plane mirrors inclined in metallic structure that converge to the solar radiation in a central focus, the reactor.These experiments were tested with water and sugarcane bagasse, which enabled the characterization of reactors, in order to improve them in the drying process. From these experiments, using the Abaqus software and the Finite Element Method (FEM), the most efficient reactor was modeled and analyzed both in steady and transient state. From the boundary conditions obtained in the experimental phase, it was possible to find the temperature variation over time, the thermal stresses, deformations and displacements of the structure, in a way that was quite convergent with the tested results.Finally, it was also concluded that the radiation reached in the reactor was a preponderant factor in the efficiency necessary for drying the bagasse, since there was a non-uniform distribution of stresses and, consequently, finding weaknesses in the areas of discontinuities of the structure of the reactor. reactor. This resulted in greater stresses and deformations, locating possible fatigue failure points.

Façades are directly exposed to external degradation agents, in particular, climatic agents. The action of degradation agents, through degradation mechanisms, leads to the deterioration of the façade throughout its useful life. Inspection and damage mapping are essential tools for obtaining data for the study of façade degradation, allowing the identification, location, and quantification of existing anomalies. Anomaly identification is not simple, especially when the only means used is the analysis of images or orthomosaics of the façade, requiring the existence of procedures that help in the detection. Understanding and improving inspection and damage mapping techniques are essential to facilitate and increase the reliability of these processes. The purpose of this study is to present a systematization for anomaly identification and damage mapping of mortar coating façades in the Federal District, including the use of Remotely Piloted Aircraft (RPA) in the inspection. The photographic survey of the façades studied is carried out using RPA and orthomosaics are obtained using orthogonalization and digital image processing methodologies, for comparison. For anomaly identification through the analysis of orthomosaics, a categorization by typology is proposed, in which the criteria position, configuration, grouping, occurrence, origin, and close elements are used to characterize different types of anomalies and help in their identification. A damage mapping standardization is also presented, indicating a level of approximation to be used for anomaly identification. The RPA use allows the capture of close and perpendicular images along the entire façade, making it possible to obtain orthomosaics of satisfactory quality for anomaly identification, using both methodologies used. The defined criteria are efficient for the characterization of the anomalies and the categorization by typology proposed is efficient for the precise damage identification in the orthomosaics of the investigated façades samples. The standardization of damage mapping uniforms the process, helping to obtain more consistent results. The proposed systematization leads to greater accuracy and reliability for mapping, which collaborates with the study of façade degradation.

The structures with permanent formwork made of composite materials have gained prominence in the civil construction industry in recent years due to their resistance to corrosion, high load capacity, low density, fatigue resistance, and ease of handling. However, despite the growth of research in this field, being a new method, there are challenges to be overcome and a scarcity of available experimental data. In this work, an innovative system of composite slabs was proposed, consisting of a permanent formwork made of Fiber-Reinforced Polymer (FRP) and Steel Fiber-Reinforced Self-Compacting Concrete (SFRSCC). The proposed component has a trapezoidal cross-section and serves a dual function in the composite slab, acting as formwork in the initial stage and reinforcement in service conditions. On the other hand, SFRSCC was chosen to replace the traditional reinforcement used to counteract the effects of shrinkage, usually consisting of welded steel mesh. The choice of SFRSCC is also due to its inherent properties, allowing for productivity gains in the construction process, and the hypothesis that the use of fiber-reinforced concrete may confer a more ductile behavior to the structural element, which will be verified in the tests carried out. The work was carried out according to the following steps: 1) development of an analytical model and preliminary design of the slabs; 2) production of permanent FRP formworks; 3) characterization of FRP; 4) production of composite slabs; 5) characterization of SFRSCC; 6) four-point bending tests; and 7) analysis of the results. The analytical model was based on NBR 8800, ACI 440.R, and ACI 440.2R, disregarding the tensile strength of the concrete and the compressive strength of the polymer. The production of formworks was divided between the manufacture of flat sheets and the manufacture of trapezoidal sheets, carried out using the vacuum infusion method. Subsequently, they were characterized through direct tensile tests. After the characterization of FRP, the production of composite slabs was carried out, applying a sand treatment to the surface of the permanent FRP formwork. The characterization of the concrete was carried out after a period of 28 days, and the behavior of the composite slab was determined through four-point bending tests for a clear span of 1800 mm. In total, two types of composite slabs were analyzed, with the main parameter being the variation in the thickness of the permanent formwork through the concentration of unidirectional fibers used. The flexural behavior of the composite slab revealed a predominant mode of failure by bending, with significant displacements and pseudo-ductile behavior. The slabs demonstrated effective composite action, with linear behavior up to the initial detachment load of the formwork, influenced by its thickness. Slabs with thicker sheets showed lower detachment loads and displacements. The study demonstrates that the proposed composite slab exhibits suitable structural behavior and has potential for application in the civil construction industry.

The use of pozzolanic cements has grown in the field of civil construction, so more studies are needed to understand their properties. Machine Learning (ML) techniques have been used in recent research to analyze databases of properties of materials such as concrete and Portland cement. It was noted that there is an absence in the literature of studies analyzing the prediction of compressive strength of pozzolanic cements produced by a single factory, even more so with the use of inputs that are easier to obtain. Therefore, in this study, Artificial Neural Networks techniques were used in order to predict the compressive strength of cements containing calcined clay in their composition. Physical-chemical characterization data (such as oxide and main compound contents) of cement from a single industry were used to assemble 5 databases, varying in the types of inputs adopted. Each database was used to train a different algorithm that later had its performance analyzed using quality indicators such as R², RMSE and MAPE. Two of the algorithms stood out among the others, one using oxide contents (A1) and the other with principal compound contents (B2), the first being more efficient in forecasting than the second. For A1 and B2, respectively, values of MAPE (2.36% and 3.12%), RMSE (1.204 and 1.513 MPa) and mean absolute error (0.999 and 1.300 MPa) were considered efficient according to the existing literature, despite lower-than-expected R² values (0.50 and 0.51). Through the results obtained, it was possible to make considerably reliable predictions (with low relative and absolute errors) of the compressive strength at 28 days of the pozzolanic cement. This fact makes the models produced promising alternatives for the evaluation of this property in future research.

The use of cementitious materials is common in both civil construction and dentistry. However, there is a noticeable scarcity of research that has approached the multidisciplinary comparison between these similar materials. In light of this, the Postgraduate Programs in Structures and Civil Construction (PECC) and Dentistry (PPGODT) sought to expand the knowledge about clinker-based cements, present in both fields of knowledge, through comparisons of their respective characteristics and properties, using an interdisciplinary approach. For this purpose, this research evaluated six cementitious materials, including two used in civil construction and four used in dentistry. These cements were divided into two distinct groups: Group 1, composed of three gray cements (CP V-ARI, MTA Angelus, and MTA ProRoot), and Group 2, composed of three white cements (CP-B structural, MTA Angelus, and MTA ProRoot). In their anhydrous phase, they were evaluated through X-ray Fluorescence Spectrometry (XRF), X-ray Diffraction (XRD), Laser Particle Size Analysis, and BET Specific Surface Area tests. Subsequently, in the hydrated cements, the setting time of the six cements was determined following the ANSI-ADA dental standard (ISO 6876:2012), and the compressive strength of the pastes at 1 day of hydration was measured following the ANSI/ADA dental standard (ISO 9917:2000). Finally, the microstructure of the pastes of the six cements was evaluated through XRD analysis at 1 day of hydration. The data from these tests allowed for a comparison of the behavior of the anhydrous cements and the pastes, both individually and collectively. Adaptations to the XRF and XRD tests were necessary due to the limited availability of dental cement, and these adaptations were considered effective for the study. The results revealed a similarity in the chemical composition of the cements, with the exception of the radiopacifying agents present in the dental cements, as well as the absence of gypsum in the Angelus MTA cements, which prevented the formation of ettringite during the hydration process of these cements. Furthermore, the BET specific surface areas of the dental cements were found to be higher than those of Portland cements, while the latter exhibited higher strength, whereas the Angelus MTA cements demonstrated the lowest strengths. Thus, the comparative analyses made a significant contribution to a better understanding of the characteristics and properties of these cements.

The advances in the construction industry and the growing necessity for fast, sustainable, and cost-effective construction systems have led to the creation of several new non-structural as well as structural elements. This is the case for the precast system, for which the solution of Precast Sandwich panels (PCSPs) stands out. In this context and given the specificities of the constructive process of the Precast Sandwich Panels in Brazil, this work has focused on assessing the mechanical compressive behavior of those panels under axial load. This work reports the results of three thin wythe precast sandwich panels tested under axial load. Panel reinforcement and shear connectors in the current state of precast sandwich panels in the civil construction context are evaluated. The author measured displacement at two distinct panel heights as well as along the panel width to provide load-displacement behavior at the cross-section level and broaden the experimental data on the subject. Further interpolations were made with those displacements registered in the panels, in order to illustrate the load-displacement profile of them along their height. The test results developed in this research showed good agreement with the results available in the literature. In addition, as concrete-wall panel strength equations have been linked to the compressive behavior of precast sandwich panels, a brief review of empirical formulae is also offered herein. Moreover, empirical data, since 2005, on both concentrical and eccentrical load testing available in the literature is also reported and compiled. Further axial tests on unreinforced masonry walls were carried out, also measuring displacements at two distinct wall heights. Experimental results on PCSPs showed agreement between equations proposed in the literature among that the largest displacements at cross-section level have not been observed in mid-width of panel and that the degree of composition was highly achieved.

Sensitivity Analysis of Facade Zones with Ceramic Coating.

Sandwich panels are precast walls composed of two outer layers of concrete and an insulating core, interconnected by shear connectors. The shear connectors can be manufactured in a variety of shapes and are commonly made using steel. Recently, it has been observed that the use of steel in manufacturing the connectors can lead to unwanted thermal bridges. Since then, research has focused on improving and applying connectors to eliminate the thermal bridging issue caused by the use of metal connectors. One of the most explored solutions is the use of Fiber Reinforced Polymers (FRP) as an alternative material to metal connectors. Another advancement in the field of materials used for manufacturing polymer composites that constitute the connector is the replacement of synthetic fibers with natural fibers. Natural fibers have become an alternative as they offer sufficiently high tensile strength and modulus of elasticity for certain engineering applications. One prominent natural fiber used in composite materials production is curauá fiber, which comes from a bromeliad plant native to the Amazon region. Recent studies show that the incorporation of 30% curauá fiber into the composite composition can increase its strength by approximately 60% compared to a pure epoxy sample. Given this, the objective of this work is to propose a curauá fiber-reinforced grid-type connector and determine its behavior when subjected to shear by conducting push-out tests. To achieve this, it was necessary to prepare the curauá fibers through an alkaline treatment based on sodium hydroxide. Tensile tests were performed on the matrices and composite materials to determine their properties and also aid in estimating the properties of the used fiber. The method used for composite production and for creating the grid-type connectors was the vacuum infusion system. Finally, concrete blocks representing sandwich panel walls were fabricated and serve as experimental models for the push-out test. The results showed that the use of curauá fiber as reinforcement material had a greater impact on the plant-based matrix, as it increased tensile strength, resulting in composites that performed similarly to synthetic matrix composites. It was also demonstrated that the application of the curauá fiber-reinforced grid connector in sandwich panels is feasible as long as a larger quantity of connectors is used to compensate for the panel's loading forces

The natural or accidental deterioration of large structures and the growing complexity of projects demand constant monitoring of the health of constructions. This process enables interventions, with the aim of avoiding catastrophic failures and also reducing costs with repairs and replacement of structural components. In this sense, damage assessment methods based on variations in the modal properties of structures were widely studied, due to their global assessment capabilities. However, some challenges were presented to the practical application of these methods, such as the loss of information on the structure's vibration signals during the modal identification process and the small variations recorded in parameters such as natural frequencies, making it difficult to assess the state of a structure exposed to environmental effects. In order to overcome these challenges, new monitoring methodologies that directly apply statistical techniques to the acceleration time histories obtained through monitoring have been developed. This work aims to evaluate the use of statistical indicators obtained from the acceleration time history of structures as an alternative input for training and testing Artificial Neural Networks in structural damage detection methodologies. To this end, the study was carried out in two stages: in the first stage, only numerically modeled beams were studied, considering different cases of structural damage; in the second stage, numerical models and experimental data of a 3D frame were used, considering different cases of structural damage. In both stages, the structures were subjected to impacts and the acceleration signals were extracted for further processing in the form of statistical indicators, which in turn were used to train and test the Artificial Neural Networks proposed for structural damage detection, varying and analyzing factors such as the number of neurons in the hidden layer, the network activation functions, the need to filter the noise of the experimentally obtained time series and the effect of peak amplitudes of accelerations in the training of the networks. The tests showed good performance using statistical indicators as parameters for training networks for damage detection.

This study represents a significant advancement in the development of sustainable solutions for precast wall sandwich panel connectors. Unlike previous research that focused on addressing the issue of thermal bridges caused by metal connectors, which impairs the energy efficiency of buildings, this pioneering work aimed to evaluate the mechanical behavior of connections using connectors made of Short Curauá Fiber Reinforced Polymer (CuFRP). One of the main innovations involved replacing widely used glass fibers with plant-based curauá fibers, with the goal of reducing the environmental impact associated with the production of these connectors. These fibers come from renewable sources and require low energy consumption in their extraction process. It's important to note that no previous study investigated the use of plant-based fibers in the manufacturing of these connectors, making this research groundbreaking in this regard. The behavior of the connections was determined and compared with connections produced using perforated Glass Fiber Reinforced Polymer connectors (PERFOGFRP), considering load-carrying capacity and ductility. The push-out test results demonstrated that connections with perforated CuFRP connectors, or rather, PERFOCuFRP connectors, exhibited shear strengths ranging from 84.82% to 41.17% of the strengths obtained with PERFOGFRP connectors. Furthermore, these connections displayed higher displacement corresponding to peak load and lower stiffness compared to similar connections tested previously. Although they exhibit lower load capacities and stiffness, connections made with PERFOCuFRP connectors can be a viable alternative to the currently used connectors, provided that adaptations in design are made. For instance, while an 8.00 m x 3.00 m sandwich panel requires the use of 0.52 m of PERFOFRP connectors to achieve the same load-carrying capacity, if PERFOCuFRP connectors are used, the same panel would require 0.62 m of connectors. This represents a 20% increase in the quantity of required connectors when opting for the connectors studied in this work as opposed to those manufactured with GFRP.

The Urban infrastructure is one of the main factors in the economic growth of a country or region, where the development of new technologies and construction processes combined with the competitive demands of the market encourage the adaptation of bridge projects to the uncertainties and variability of their calculation parameters. This work analyzes the loads and weighting coefficients adopted by the Brazilian standards and the international standards AASHTO LRDF, ACI 318-14 and Eurocode, in order to assess which standard is more conservative. The results evaluated were obtained by means of a case study processed with the aid of CSiBridge software, analyzing loads and coefficients applied to different bridge lengths, in order to quantify the variation in the design of the superstructure when it is designed according to the approach of each of the standards. In addition to the design considerations applied to each standard individually, the permutation of the application of the coefficients between the standards was considered, with the additional impact coefficient, number of lanes coefficient and vertical impact coefficient belonging to the Brazilian standard; the multiple presence factor to the American standard; and the adjustment factor for double axle loads and adjustment factor for uniformly distributed loads to the European standard. It is possible to see a more conservative approach for the Brazilian standard, followed by the European standard, with the American standard being the least conservative. By smoothing out the loads, forces and reinforcements obtained, the conservatism observed for the Brazilian standard is reflected in the simplicity of the methodology used to apply the mobile load, which nevertheless presents efficient results when compared with the proposed international standards.

Wind energy generation has established itself as a sustainable alternative in the energy matrix whose installed power has consistently grown over the years. The development of new wind turbine designs with large nominal capacities and dimensions makes it essential to study the vibrations of their structures and devices that can reduce their displacements. This work uses analytical and numerical approaches for dynamic analysis of horizontal axis wind turbine structures, also evaluating the effects of using tuned liquid column dampers (TLCDs) as passive devices to reduce structural displacements. Computational routines were developed to simulate wind turbines by discretizing the towers into beam finite elements with subsequent application of the static condensation process to eliminate the system's rotational degrees of freedom. The implementations were introduced in a new version of the software DynaPy, allowing the analysis of these structures equipped with TLCD and subjected to harmonic excitations and seismic loading. Furthermore, an analytical approach was used to represent the structure as a single degree of freedom system with generalized properties, from which parametric TLCD analyses were conducted to assist in the optimal sizing of the device. The natural frequencies and mode shapes obtained through the model with static condensation showed good agreement with the referential values when the rotational inertia of the mass at the extremity is ignored. When considering this parameter, accuracy became restricted to the first mode. Despite this, the model was well suited to determining the structure's response in the time domain, which was also observed for the simplification method with generalized properties. Analyses of the structure equipped with TLCD on DynaPy demonstrated the device's efficiency in reducing vibrations. It was also possible to visualize the influence of the number of TLCDs and the opening ratio of the diaphragm on the behavior of the structure and liquid column of the attenuator. Finally, the parametric analysis confirmed the importance of choosing a tuning ratio close to the unity value when sizing the TLCD. It also indicated an increase in the device's efficiency as the mass and aspect ratios were set to higher values.

Although most research on punching shear is related to internal columns, the study of the behavior of the 

slab-column connection with a re-entrant corner is essential due to the frequent use of this connection in 

buildings. Therefore, the present work aims to experimentally analyze the punching behavior of reinforced 

concrete flat slabs supported on re-entrant corner columns, with the main study variable the shear reinforcement 

rate. The experimental program consists of three slabs supported on columns with a square section of 300x300 mm. 

One of the slabs did not have shear reinforcement, while the others were reinforced with different rates of double 

headed studs, positioned radially in relation to the column. All slabs had the same flexural reinforcement ratio (0.96%)

 and were subjected to the same load eccentricity. With the analysis of the experimental results, it was observed that 

the monitored studs presented good performance, especially in the first and second layer of distribution. 

The use of shear reinforcement provides an increase in resistance at levels between 14% and 21%. 

A database was assembled with the results of this research and Albuquerque (2015). 

The results were evaluated in accordance with the prescriptions of ABNT NBR 6118 (2014), ABNT NBR 6118 (2023),

Eurocode 2 (2004), prEC2 (2022), ACI 318 (2019) and fib Model Code 2010 (2013).

This thesis proposes a strategy using radial basis function (RBF) as surrogate models for uncertainty quantification of non-linear and time-dependent problems. The models surrogates with RBF are trained to replace the time-consuming integral evaluations that determines the time-dependent energy release rate for a problem in energy mechanics. age- and time-dependent fracture. These surrogated templates are also used to replace the output responses of performance functions consisting of non-linear problems selected from the literature. The performance of models surrogated with RBF was validated through cross-validation and Monte Carlo simulations that exhaustively evaluate the integrals and the functions of non-linear and time-dependent problems. The results of quadratic errors means and Kolmogorov-Smirnov fit tests for probability and density functions predicted cumulative values, demonstrated that the models surrogated with RBF achieved good accuracy for small training sets. In addition, a new compact support RBF was introduced. for surrogate modeling processes. The results predicted by the models surrogated with the new RBF demonstrated a good efficiency for the presented problems of quantification of uncertainty of functions non-linear with relatively small training sets. The models surrogated with RBF presented generalization capabilities to predict thousands of unknown data obtained from Monte Carlo simulation and successfully evaluate fracture mechanics and function problems non-linear.

This work formulated and implemented continuous and discontinuous approaches to predict failures in quasi-brittle materials for mode I and mixed (I+II) fracture behavior: a three-dimensional isotropic damage approach based on the thermodynamics of irreversible processes, and an approach that combines the advantages of Cohesive Zone Model by the extrinsic Park-Paulino-Roesler law and Generalized Finite Element Method. The damage evolution laws are based only in physical parameters from fracture mechanics, which can be obtained through fracture and resistance tests without the need of further calibration. The Park-Paulino-Roesler law can be applied for various types of fracture modes. Both approaches were tested and validated by comparison with a several benchmark problems in mode I and mixed mode conditions from the literature. The comparison showed the efficiency and accuracy of the approaches to predict the tensile strength and the entire loaddisplacement curves of the experiments for various levels of mesh refinement, including very coarse meshes. The result of this research is two robust  approaches capable to simulate complex fracture behavior of quasi-brittle materials.

Civil construction plays an important role in a country economic and social development, but it is also a major waste generator. Cement packaging is one of those wastes, which can be recycled and reused as a fiber in cementitious matrices. There are several studies on composites using vegetable fibers, however, the studies regarding the use of kraft fibers in Portland cement matrix are recent and do not address its behaviour in the alkaline environment. This work aims to study the chemical and microstructural characteristics of a composite, in order to comprehend the durability of kraft fibers when inserted in alkaline environments, such as Portland cement. Therefore, experimental tests were performed and divided into four stages: material composition; composite production; evaluation of fibers in different alkaline media and composite characterization. To produce the composites, Portland cement, kraft fibers and water were used. Analyses were performed with different kraft fibers addition ratios (reference, 0.5%, 1.0% and 3.0%) and water/cement ratios (0.40, 0.45 and 0.50). From the results, it can be seen that kraft fibers can be used in cementitious matrices, since they obtained a low inhibition index. Also, there was no delay in the hydration of Portland cement due to the inhibitory components present in the kraft fiber. Moreover, there was a reduction in the content of CH (calcium hydroxide) in the cement pastes, which is beneficial, because this is responsible for the mineralization of the kraft fibers. The mineralization is a phenomenon observed in the fiber immersed in calcium hydroxide solution, due to the high pH of the solution and migration of products to the fiber structure

This thesis presents a novel Bi-Fidelity Multi-task Learning Model based on a Deep Neural Network (BFMT-DNN) to address the computational challenge of structural reliability analysis applied to complex structures. The main contribution is the development of a novel hyperparameter-optimized BFMT-DNN, that considers the advantages of Bayesian Optimization, focusing on prediction accuracy, stability, and computational efficiency to accesses the reliability of high nonlinear problems. For constructing this surrogate model, the study proceeded throughout two stages before. Firstly, is presented a method based on a Bi-fidelity Kriging surrogate model associated with Subset Simulation for structural reliability analysis. The efficiency of the bi-fidelity Kriging model is evaluated using a stiffened panel reliability problem that demands high computational costs, such as non-linear finite element analysis structural models. The next step proposed a two-stage Bi-Fidelity Deep Neural Network surrogate model in association with Subset Simulation to quantify the uncertainty of structural analysis and assess the probability of failure of high dimensional rare events. In the two steps, the surrogate models can reproduce the non-linear behaviour in the variable's uncertainty analysis, reducing the high computational demand of these problems. Furthermore, the BF-DNN surrogate model used Bayesian optimization to fine-tunning the hyperparameters. The multi-fidelity models used low-fidelity data samples added to the model to predict high-fidelity responses, and, when presenting a good correlation between the fidelities, the assessment of the proposed method showed that the proposed Multi-fidelity Method is a good strategy because it can provide an accurate probability of failure estimation with a lower computational cost. A hyperparameter-optimized BFMT-DNN using low-fidelity data samples added to the model to predict high-fidelity responses for structural collapse behaviour framework is presented in the final analysis. The assessment is realized in an offshore wind turbine in extreme conditions and described using non-linear Finite Element analysis to obtain multiple outputs. The results show that the proposed multi-fidelity methods can give a precise failure probability estimation with less computational cost.

One of the most used materials in the world is Portland cement. In this way, it is natural to invest more and more in researching new materials that, when added to cement, will give it other properties and/or reduce operating costs. Among these materials there is calcined clay, a pozzolanic mineral addition that gives the cement, among other improvements, less heat of hydration and lower production cost. Another material that should be mentioned is nanosilica, considered a highly reactive addition, currently applied to cementitious materials with unique behavior due to its reduced size. These materials provide substantial improvements to cementitious materials, however, the effects caused by nanosilica associated with calcined clay are still poorly studied. Thus, this work deals with the experimental investigation of the effect of the addition of nanosilica, individually and together with two types of calcined clay, in Portland cement pastes, aiming to contribute to the study of nanotechnology applied to cementitious materials. The experimental program is divided into four parts: (1) Production of calcined clay, using controlled temperature in a muffle furnace; (2) Characterization of the materials studied in the research; (3) Determination of the performance index of binary and ternary mixtures, with Portland cement, nanosilica, inert filler and calcined clays; (4) Study of the microstructure of Portland cement, nanosilica, inert filler and calcined clay pastes. Microstructural analysis techniques will be used for this study: x-ray fluorescence, x-ray diffraction, calorimetry, thermal analysis (TG/DTG), scanning electron microscopy, infrared spectroscopy, mercury intrusion porosimetry and nuclear magnetic resonance. It is expected that the results demonstrate the potential to use these additions for the production of high strength concretes, as a synergistic effect is observed in binary and ternary mixtures.

The nanosilica (NS) provides changes in the microstructure of cementitious composites such as densification of the cementitious matrix that result in increased of mechanical strength and durability of these composites. Despite this improvement, the NS contributes to potentiate undesirable effects in cementitious composites, such as autogenous shrinkage. Thus, this research project aims to verify the effect of NS functionalization with different mass ratios of shrinkage reducing additive (SRA) in Portland cement pastes. Four functionalized nanosilicas were produced, one with amine groups (NSFA) and three with different mass ratios of ARR/NSFA (5%, 10% and 15%), called NSFArr. These samples were characterized using dynamic light scattering (DLS), Zeta potential, thermogravimetric analysis (TGA), infrared spectroscopy (FTIR) and nuclear magnetic resonance (²⁹SiNMR). The properties of six different pastes and microconcretes were investigated, one being produced only with Portland cement CP V-ARI and five replacing 1% of Portland cement by NS or the functionalized nanosilicas. Time zero, autogenous shrinkage, heat of hydration, compressive strength at 2, 7 and 28 days of hydration, amount of CH and C-S-H through X-ray diffraction (XRD), TGA and FTIR, as well as the porosity at 28 days of hydration through the mercury intrusion porosimetry test (PIM) were analyzed. It was possible to observe changes in the hydration kinetics with a delay in the induction period of the pastes with NSFArr compared to the other pastes, which did not influence the mechanical performance at the initial ages. In addition, NSFArr mitigated the autogenous shrinkage, increased the pozzolanic reaction and promoted an increase in mechanical strength between 7 and 28 days. It was possible to conclude that the functionalization method used was efficient to promote the coupling of the SRA functional groups on the surface of the nanoparticles and that the mass ratio of 10% was the one that presented the most promising results for use in cementitious composites.

Due to the application of cyclic loads, the length of an existing crack in a structure increases over time, resulting in a higher stress concentration around the crack tip. Consequently, this leads to an increase in propagation rate and a decrease in the residual strength of the structure. After a certain period, the residual strength becomes so low that the structure can no longer withstand service loads. This study introduces a novel approach to assess two-dimensional elastoplastic models in a crack propagation scenario. The approach is based on the boundary element method and its dual formulations.
The adopted methodology consists of two steps: the first step involves simulating elastoplastic behavior, considering initial stress processes and enabling the treatment of various yield criteria without considering incompressibility of inelastic deformations. In this stage, the domain integral due to non-homogeneous terms in the plastic region is transformed into a boundary integral using the Dual Reciprocity Method (DRM), the first dual formulation. Local behavior "poliharmonics splines" functions are utilized for this purpose. Furthermore, the plastic calculation employs the J-Integral to compute the Stress Intensity Factors (SIFs).
The second step aims to incrementally simulate the crack propagation path using the in-house software BemCracker2D for crack modeling and analysis. This is based on Elastoplastic Fracture Mechanics (EPFM) and the Dual Boundary Element Method (DBEM), the second dual formulation. To validate the adopted methodology and accurately simulate the mechanical behavior of cracks in the plastic regime of the material, six models of 2D plates with straight and inclined edge cracks are employed. Three plasticity criteria (Tresca, von Mises, and Gao) for perfectly plastic materials are used. The numerical results are compared with classical models from the literature, demonstrating the efficacy of BemCracker2D in predicting the plastic zone using DRM at the crack tip. The same program exhibited excellent prediction of the propagation path and determination of mixed-mode plastic stress intensity factors in crack treatment.

The growing demand for electricity as a need for sustainable development has made many countries look for renewable sources of energy as well as a replacement for energy from fossil and nuclear fuels. In this context, design, construction and dissemination of wind turbines have become more relevant, which use devices to convert the kinetic energy of the winds into electrical energy. Wind turbines are flexible structures subjected to dynamic actions of winds and sea waves and may suffer undesirable vibrations that affect their safety and operability. The types of control that can reduce these vibrations are classified into passive, active, semi-active and hybrid. An example of passive control is an inverted pendulum which dissipates the mechanical energy of the main system, when correctly tuned to the structure, since it vibrates in phase difference in relation to the main system. The work proposes to couple an inverted pendulum to the tower of a floating offshore wind turbine to reduce the rotation vibrations of the tower when the wind turbine is subjected to the dynamic actions of winds and sea waves. Five parameters from inverted pendulum are optimized through Frequency-Response Function, considering two criterions: tower peak rotation and tower variance rotation. Once an optimal inverted pendulum configuration is defined, the Monte Carlo method is used to evaluate the random actions in the time domain and Davenport spectrum and Pierson-Moskowitz spectrum are used to evaluate, respectively, the randomness of the wind and waves in the frequency domain. The vibration reductions in the tower rotation through the deterministic analysis were around 90% for both actions. When subjected to the random action of the wind, the reductions in the maximum peak of the tower rotation were 65% in the time domain and 70% in the frequency domain. The vibration reductions in probabilistic analyses are smaller than in deterministic analyses because the spectrum energy is not concentrated in only one frequency, but distributed over a frequency range. Nevertheless, the relative error between the random responses obtained in the time domain and in the frequency domain is less than 10%. When the wind turbine is subjected to the random actions of the sea waves, the reductions in the tower vibrations are insignificant. This happens because the highest concentration of energy in the Pierson-Moskowitz spectrum occurs at a frequency far from the fundamental frequency of the structure. Besides that, the relative error between the responses obtained in the time domain and in the frequency domain is small. In this way, it was verified that it is possible to optimize the inverted pendulum parameters from a deterministic analysis and achieve significant reductions in tower vibration when the wind turbine is subjected to random excitations. 

The BIM process emerged in the AEC industry with the proposal to develop a digital model of a building to assist the project conception, the building process and the management and maintenance of the building. These models have a large amount of information that constantly needs to be exchanged between the various disciplines involved in the project. As these disciplines use different tools for reading the model’s information, it is important to guarantee a complete exchange of information to avoid correction and/or addition of data. The nonproprietary IFC file was created so that there would be interoperability between the different software that are based on the BIM process. However, due to the complexity of the digital models and the wide variety of software that may be involved in the project, it is still common for information to be lost. Because of that, there was a need to use methodologies that would help in the interoperability process and promote the semantic enrichment of IFC files. Among these methodologies, machine learning has been gaining ground, with its various techniques that use the learning from experience process to predict new information. This paper proposes and validates machine learning (ML) models and strategiesto promote the semantic enrichment of Building Information Modeling (BIM) to improve interoperability among architectural and engineering applications. Various ML techniques (k-Nearest Neighbor, Bagged Tree, SVMGaussian, SVM-Quadratic e SVM-Cubic) were implemented to classify room types of residential building models. In addition to traditional binary classifiers, it was proposed two voting techniques, namely multiclass-binary and ensemble, to improve the accuracy of the classifications and decrease overfitting during the training process. Real architectural design data of residential buildings with 8 different classes of rooms were used to train the classifiers in scenarios with different feature variables selection. The results demonstrate that the voting techniques can be successfully used as semantic enrichment strategies to accurately predict the residential room classes using few and easy-to-obtain features from IFC files. The proposed strategies and techniques improved the interoperability of BIM models in efficiently classifying residential rooms without the need for human intervention.

Throughout their useful life, the facades of buildings are under the action of degradation agents. Among the degradation agents, those of thermal origin exert a strong influence on ceramic facade coverings, since the requests generated by the action of these agents result in dimensional variations that induce tensions at the interfaces of the layers, which can generate anomalies. To ensure performance and minimize the appearance of anomalies, inspection routines must be established. Among the inspection tools is infrared thermography, a nondestructive, non-contact, real-time measurement test. The thermograms obtained are analyzed qualitatively or quantitatively. The objective of this study is to define criteria for quantitative analysis of thermograms. The anomalies of detachment in facades with ceramic coating of three buildings located in Brasília-DF are investigated. In this study, the passive approach and qualitative and quantitative analysis of the thermograms obtained are used. A quantitative analysis routine is proposed based on criteria obtained in the investigation of areas without the presence of anomalies and areas with anomalies. These criteria are used to determine the Delta T and Delta Tcor thermal contrasts. The TSAREF reference criterion of the no anomaly zone is used in the Delta T correction to determine the Delta Tcor. The Delta Tcor proposal aims to provide an indicator for the detection and evaluation of ceramic facade detachments. In this study, the indicator is that from Delta T of 0.11 °C and Delta Tcor of 0.005 °C/°C in stage A (period from 07h to 12h) and Delta T of -1.50 °C and Delta Tcor of -0.066 °C/°C in stage B (period from 16:50 to 20:00 h) there is the presence of ceramic detachments. The quantitative analysis routine proposed in this study can be applied in the investigation of ceramic detachments located in different buildings, in different locations in Brasília-DF and exposed to different climatic conditions and heat flow.

Numerical analysis of steel bars with flattened ends of three-dimensional trusses.