Papers by Marcos Massao Futai
The global-local modeling methodology is used to evaluate specific regions of a structural system... more The global-local modeling methodology is used to evaluate specific regions of a structural system. A global model represents the entire system under study, while critical domains are assessed in detail by a submodeling routine employing more refined models. The advantages of this hierarchical modeling are related to reducing the need for complex transition regions in solid elements and the versatility in testing different geometries in the submodel region. Furthermore, it allows for a reduction in the computational power required to solve the problem. However, ensuring a good transfer of the boundary conditions between the different models is essential. For large and complex infrastructures, such as bridges, numerical analyses sometimes become time-consuming when more complex evaluations are required. Therefore, using simplified models to reproduce global behavior and more complex modeling strategies in critical locations can be an alternative to comply with this requirement. The present paper aims to employ a global-local approach to analyze a reinforced concrete railway bridge. Thus, the global and local models employed numerical analyses using solid tetrahedral finite elements. The local region presented a greater mesh discretization for the submodeling. Additionally, the local model allows inserting steel reinforcement details and specific constitutive laws for the materials utilized in the described region of the railway infrastructure. The obtained results enable the evaluation of the formation and propagation of cracks and the identification of damages located in the structural elements with greater precision. The methodology can improve condition assessment and support the inspection and maintenance of critical infrastructure assets.
Revista IBRACON de Estruturas e Materiais
The evaluation of service conditions of concrete structures has still been carried out through im... more The evaluation of service conditions of concrete structures has still been carried out through implicit knowledge based on the expertise and knowledge of inspectors, who classify structures based on subjective criteria. The main degradation mechanism of reinforced and prestressed concrete structures is the corrosion of steel reinforcements, with expressive maintenance and repair costs. The phenomenon of corrosion in concrete structures has a complex behavior and presents several uncertainties, and deterministic analyzes can produce very conservative responses, which can unnecessarily increase maintenance costs, thus justifying probabilistic approaches. This article then presents a systematic literature review of articles that address the evaluation of concrete structures under reinforcement corrosion using a probabilistic approach. In this regard, 94 journal articles obtained through an appropriate review protocol were reviewed. Thus, the summary of the main proposed methodologies w...
Geotechnical and geological engineering, Apr 13, 2024
Springer eBooks, Dec 12, 2021
Construction and Building Materials, Aug 1, 2021
Abstract Surface roughness of coarse aggregates, regardless of its known influence in the bonding... more Abstract Surface roughness of coarse aggregates, regardless of its known influence in the bonding strength with the cement paste in the hardened state and in the viscosity of the composite in the fresh state, it still a barely researched and discussed topic. In addition, little is known about what rock characteristics influences the multiscale roughness of aggregates. This paper aims to evaluate the roughness of distinct types of aggregates in multiscale (macro and micro scale of roughness) using a 3D interferometer and establish a quantitative relation between the granulometry and mineral composition of the rocks and the surface roughness of aggregates. Six types of aggregates, five crushed and one gravel from riverbed, with sizes ranging from 19 to 25 mm were scanned. One sample from each type was chosen for a petrographic analysis. The six types of aggregates analyzed showed statistical differences between them in macro and micro scales of roughness. In the microscale roughness, basalt was considered the smoothest, and surprisingly, the quartzite (gravel), were one of the roughest. In the macro scale roughness, the quartzite (the gravel) was smoother than all the other samples due its rounded shape, while the gneiss was the most irregular particle and had the highest roughness. The quartzite (gravel) is a good example of how an aggregate could be very rough in a microscale (invisible to the naked eye), comparable to crushed aggregates, while being smooth to the touch and rounded. The weathering seems to affect the roughness at micro(nano)scales, independently of the roundness shape observed at millimetric scale. The micro scale roughness appeared to be related to the average size of the grains, the smaller the average grain size, the lower the micro scale roughness is. Rocks with aphanitic textures tends to fracture in smoother surfaces than rocks with phaneritic textures.
Geotextiles and Geomembranes, Aug 1, 2022
The use of fiber optics as a tool for different kinds of geotechnical monitoring can become highl... more The use of fiber optics as a tool for different kinds of geotechnical monitoring can become highly attractive and cost effective when compared to conventional instruments such as piezometers, inclinometers, among others. A single fiber optic cable may cover a larger monitoring area compared to conventional instrumentation, and the possibility of monitoring more than one physical quantity with the same fiber optic cable. Consulting the literature, it is possible to find several different examples where distributed fiber optic systems are being used. For the use of any sensor, a calibration curve is required. In the case of strain sensors, calibration is required to derive strain values from the frequency measurement quantity. However, fiber optic sensor cable manufacturers often do not provide their own calibration parameters and consult the values in specialized literature, which can result in monitoring errors. In this context, this article presents a bench adjusted for tests on single mode fiber optic cables, as well as results of tensile tests aimed at defining the function of strain variations of two different optical fiber cables, manufactured by different companies, using two different distributed interrogators. This paper also proposes a methodology for calibrating of the fiber optic cables deformation since the calibration parameters are provided by the cable manufacturers, which can result in errors depending on the application. It should be noted that there are few manufacturers of fiber optic cables aimed at application in civil engineering. Therefore, with the calibration methodology proposed in this paper, it is intended to transmit to the academic community the possibility of obtaining calibration parameters of any fiber optic cable, even those manufactured for telecommunications purposes and not only for cables manufactured with the intended use in civil engineering. Because of this fact, researchers will not be restricted to the acquisition of special cables for their applications. Based on the results, it was possible to conclude that the application of calibrated fiber optic sensors in experimental piles foundations is viable, in order to evaluate the load-displacement behavior of these elements, under different loading conditions.
Soils & rocks, 2015
When soils are inundated with liquids other than water, a physicochemical interaction takes place... more When soils are inundated with liquids other than water, a physicochemical interaction takes place and can alter the soil behavior. Depending on the type of soil and on the solution, the soil can become more compressible and lose strength (or the contrary). In this paper, tropical residual gneiss soils are used, namely lateritic and saprolitic soils. The solution used are a mixture of sodium hexametaphosphate and sodium carbonate. Solutions were prepared with different concentrations such that the pH value remained at 10.5. Sodium concentration was used to interpret the results. Oedometer and triaxial compression tests were carried out with samples permeated with these solutions. The lateritic soil behavior was found to be quite distinct from the saprolitic one. While the lateritic soil becomes much more compressible upon the increase in the concentration of sodium, the saprolitic soil swells progressively. However, the compression curve converges at more elevated stress levels. The stress-strain curve also alters in relation to the concentration. The lateritic soil loses strength and its stiffness is greatly reduced with the increase in concentration.
Revista IBRACON de Estruturas e Materiais, 2024
Ensaios não destrutivos para avaliação do desempenho de concreto autocicatrizante por adição de m... more Ensaios não destrutivos para avaliação do desempenho de concreto autocicatrizante por adição de microcápsulas contendo metacrilato de metila
Revista IBRACON de Estruturas e Materiais, 2023
The corrosion of steel rebars is the main cause of reinforced concrete degradation, which results... more The corrosion of steel rebars is the main cause of reinforced concrete degradation, which results in increasing costs with structural rehabilitation and repairs. As a solution, corrosion resistant rebars, such as those of FRP-Fiberreinforced polymer-, have been used to replace conventional steel. This paper describes the development of a design program that calculates the flexural FRP reinforcement of T-shape beams. The possibilities as regards the neutral axis position, failure mode and concrete linear or non-linear behavior define the design scenarios for which their respective equations were deduced. The flexural strengths computed using the deduced equations showed agreement with experimental results for 125 beams, validating the proposed methodology. Since FRP rebars are vulnerable to creep rupture, the sustained stresses must be lower than the maximum allowed by ACI 440.1R-15, which may require increases in areas, modifying the flexural strength. Therefore, the equations to compute the new neutral axis depth and flexural strength based on the adjusted area were deduced and implemented in the computational program. Subsequently, this paper presents design examples considering all scenarios for which the equations were deduced. The design of one Tsection considering different FRP rebars combined to normal and high-performance concretes is also reported. The results showed that beams reinforced with aramid and glass FRP required large areas to avoid creep rupture, whereas the areas of those reinforced by carbon FRP rebars were considerably small; however, they exhibited small curvatures and fragile failure when under-reinforced.
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Papers by Marcos Massao Futai