cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14307317
title: Reinforced concrete beams coated with fiberglass-reinforced polymeric profiles as partial substitutes for the transverse reinforcement

description: abstract: The use of GFRP (Glass Fiber Reinforced Polymers) structural profiles in the construction sector is growing due to their attractive properties, such as high mechanical strength and durability in aggressive environments. With this, it is necessary to conduct studies that deepen the knowledge about the performance of these materials in structural applications. Therefore, this work aims to analyze the mechanical performance of reinforced concrete beams coated with GFRP profiles, in comparison to reinforced concrete beams, by analyzing groups with different spacing between transversal reinforcement. In all groups there was no change in the longitudinal reinforcement, and the D and Q groups were, respectively, made up of transverse reinforcement spaced twice and quadruple the one calculated for the reference beams, and presented the GFRP profiles in their constitution. All beams were tested at four-point bending, and strain gauges were installed in one of the beams of each group studied. The results obtained in the tests showed an increase in strength of 83.67% in the beams of group D, and 79.91% for group Q, in relation to the references. The analysis of longitudinal deformations made it possible to verify increases in stiffness and the moment of cracking in composite beams. Thus, based on this study, the composite structures studied may constitute future solutions for constructions exposed to aggressive environmental conditions, in order to increase their durability and also to contribute to the design of such structural elements with lower reinforcement rates.
DOI: 10.6084/m9.figshare.14307314
title: Numerical analysis of the influence of block geometry on the behavior of piled foundations

description: abstract: In recent years, engineering has significantly increased the use of numerical modeling, mainly applied in studies of solutions and analysis of the behavior of the soil - structure and foundation element interaction. In this sense, this paper analyzes the behavior of blocks foundations made up of one, two, three and four piles with 25 cm in diameter (d) and 5 m in length (L) and with unusual spacing between the piles, equal to 5d in a three-dimensional finite element numerical model (MEF-3D). The results of the numerical analyzes demonstrated an average contribution of 36% due to the block-to-ground contact in relation to the total capacity of the system. The geometry of the block influences the response in terms of load capacity and stiffness of the foundation element. These results demonstrate an opportunity to reevaluate traditional calculation requirements, with the aim of rationalizing the design of foundations, thus improving the safety of the structural system.
DOI: 10.6084/m9.figshare.14307311
title: Experimental analysis of the structural behavior of different types of shear connectors in steel-concrete composite beams

description: ABSTRACT: The present work aims to compare the structural behavior of steel-concrete composite-section beams for three types of shear connectors made of U hot rolled section and cold-formed sections of U and L. Experimental tests were performed with the three types of connectors associated with I section laminated steel beams and reinforced concrete slabs. For each type of connector, three push-out tests were performed, as well as six simple supported beam tests to evaluate the positive bending moment region. The results indicated that the direct shear behavior among the different types of connectors presents significant differences, however they do not significantly influence the average flexural strength of the composite beams. These, however, present considerable differences in deflections and deformations due to the stiffness differences of the connectors.
DOI: 10.6084/m9.figshare.14307308
title: Influence of the cracking consideration in the displacements of a shallow tunnel lined in steel-reinforced concrete: numerical model

description: abstract: The study of shallow tunnels introduces different aspects when compared to deep tunnels analysis. Among these characteristics can be emphasized the non-uniform shape of the deformed cross-section and the impossibility of some simplifications such as the consideration of homogeneous stresses around the excavation. Since the tunnel lining is subject to combined bending and compression, shallow tunnels are more susceptible to the development of final tensile stresses (not founded in deep tunnels) and the consequent concrete cracking. This paper presents a numerical simulation in finite elements with the ANSYS software. The purpose of the study is to analyze the cracking influence in the displacements of shallow tunnels, treating the concrete behavior by three different models: elastic, viscoelastic and viscoelastic with cracking effects.
DOI: 10.6084/m9.figshare.14307306
title: Metal magnesium industry waste for partial replacement of Portland cement

description: ABSTRACT: The high demand for concrete has triggered studies on the mitigation of Portland cement production impacts, such as greenhouse gas emissions and energy demands, in addition to enabling cost reduction. Partial replacement of cement with other materials has been employed as an alternative to minimize the damage caused by the cement industry. In this regard, it is necessary to use materials that efficiently replace cement clinker. This study uses waste generated from the production of metallic magnesium as a partial replacement for Portland cement. The substitution is aimed at reducing the amount of clinker used, as its production necessitates high energy consumption and results in emission of large quantities of CO2 into the atmosphere. The tailings were characterized via X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and granulometric analysis. For evaluating the mechanical behavior and porosity, 25% of the cement (by mass) was replaced with tailings, and the resulting composite was molded into cylindrical specimens. After curing for 28 and 91 days, all specimens underwent compression testing. The results of the physical characterization showed that more than 65% of the tailing grain was lesser than 45 μm in size, which contributes to the packaging effect. In terms of the chemical and mineralogical composition, the tailing had high levels of calcium, and the predominant phases could be identified. The compressive strength of the mortar with substitution was higher than 40 MPa. The convergence observed between the results of the different characterization techniques demonstrates the efficiency of using the waste as a supplementary cementitious material.
DOI: 10.6084/m9.figshare.14307305
title: Concrete produced with recycled aggregate: a durability analysis for structural use

description: abstract: Construction and Demolition waste (CDW) is already used in many European countries as recycled aggregates to produce concrete for structural purposes. In Brazil, its use is still restricted to concretes with no structural function. The consumption of aggregates for the production of concrete is very large, and enabling the use of recycled aggregates in the production of concrete is essential to transform the civil construction industry into a more sustainable one. This work aimed to study the parameters that affect the durability of C30 grade concrete, produced with different types of recycled aggregate. We defined four types of coarse aggregates for carrying out this work: the natural (AN), the concrete (ARCO), the cementitious materials (ARCI) and the treated cementitious materials (ARCI Treated). We adopted 30% substitution content of natural aggregate for recycled aggregates. The treatment of the ARCI aggregate consisted of the application of water and cement solution, aiming to reduce its water absorption capacity. We determine the physical and mechanical characteristics of the concrete, in addition to carrying out indirect measurement tests of durability, by determining the permeability to air, penetration and migration of chloride ions, and determination of the carbonation depth. The results indicate that the concrete using the ARCO type aggregate, produced with 100% crushed concrete, presented characteristics like the reference concrete, indicating the possibility that it can be applied to reinforced concrete structures. As for the ARCI type aggregate, it presented inferior results when compared to the concrete reference for the tests of indirect measurement of durability, however, the concrete displayed good mechanical properties. The concrete produced with the treated ARCI did not perform better than the concrete with ARCI for most of the evaluated characteristics, indicating that the proposed treatment was not adequate.
DOI: 10.6084/m9.figshare.14307302
title: Modelling of tension stiffening effect in reinforced recycled concrete

description: abstract: Concrete with recycled aggregate is a fragile material under tensile stresses. However, like conventional concrete, it is possible that its contribution is relevant in the design of reinforced concrete elements under tension or bending, even after cracking. The objective of this work is to evaluate the application of the analytical models used to predict the effect of tension stiffening on recycled reinforced concrete. Tests of reinforced concrete under tensile were performed using conventional concrete and concrete containing 25% and 50% replacement of the natural aggregate with recycled aggregate. From the experimental results of reinforced concrete, the contribution of the concrete was isolated and a parametric study was carried out to identify which analytical model in the literature may be more appropriate. The models proposed by Carreira and Chu (1986), Vecchio and Collins (1986) and Hsu and Mo (2010) were evaluated. A numerical analysis, based on the finite element method, was implemented to model the mechanical behavior of the reinforced concrete under tensile using the analytical models already adjusted to concrete with recycled aggregate. The stress distribution in steel and concrete and the cracking mode were evaluated numerically. The results indicate that the parameters used in the analytical models for conventional concrete cannot predict the behavior of concrete with recycled aggregate and need to be modified to obtain a more accurate answer.
DOI: 10.6084/m9.figshare.14307300
title: Numerical analysis of reinforced concrete shear walls with rectangular cross section

description: abstract: This study addresses a numerical analysis of reinforced concrete columns in which the lengths are significantly larger than their widths with a rectangular cross section. Numerical simulations of 1,440 cases were performed, each case simulated with the single bar model, isolated bar model and mesh model, in addition, 3D model simulations were carried out. For the validation of 3D models and bar models, comparisons were made between the numerical simulation e experimental results of 24 reinforced concrete columns. Second order effects were analyzed on the vertical moment at the edge of the columns in which the lengths are significantly larger than the widths (localized second-order effects) and also the values of the horizontal moments along the cross sectional length in the mesh model. Influences of the main variables were observed influencing the behavior of the columns in which the lengths are significantly larger than their widths: the ratio between the cross sectional dimensions, the slenderness and the stresses (normal stress and bending moment around the axis of greatest inertia).
DOI: 10.6084/m9.figshare.14307297
title: Synergic effects between mineral admixtures on strength and microstructure of concretes

description: ABSTRACT: The present research aims at evaluating the physical, chemical and synergistic effects of substitution 25% cement in mass by limestone filler (LF), fly ash (FA) and rice husk ash (RHA), in similarity of physical condition (near grain size curves), and to compare the different binary and ternary mixtures of concrete after 28 days of wet curing, keeping the ratio water/cement (w/c) constant. The concrete samples were characterized in relation to the axial compressive strength and their microstructure using TG/DTA and MEV/EDS techniques. The CCA in the binary mixture was the one that obtained bigger compressive strength among the investigated mixtures, but when combined with a less reactive mineral addition in ternary mixtures, an overlap of chemical and physical effects occurred which resulted in better resistance and higher C-S-H formation in the hardened cement paste.
DOI: 10.6084/m9.figshare.14307296
title: Parametric analysis of analytical solutions of the rollover of precast beams on bearing pads

description: abstract: Due to low stiffness to lateral bending, long prestressed precast concrete beams are subject to lateral instability. For this reason, the safety analysis of these beams during the transitory stages of transport, lifting and assembly is fundamental. This work presents a nonlinear analytical model for the parametrical analysis of beams on bearing pads in their definitive location, without the effective connections being made. Such a solution determines a critical load of instability and considers the geometry of the cross-section, physical characteristics of the materials as well as geometric imperfections. A parametrical simulation is performed for the initial eccentricity, the initial rotation of the beam, concrete resistance, bearing pads dimensions, and the cross-section of the beam. The results show that the parameters of most considerable influence on beam stability are rotation stiffness of the bearing and the geometric characteristics of the cross-section of the beam, which can result in a reduction of about 50% of the critical rollover load. In addition, the cracking load may, in some cases, be close to the critical toppling load.
DOI: 10.6084/m9.figshare.14307293
title: Analysis of constructive parameters of vertical reinforced concrete structure with self-compacting concrete

description: abstract: The objective of this paper is to quantify the improvements due to the use of self-compacting concrete (SCC) as a replacement to a conventional Portland Cement Concrete (PCC) in the production of a reinforced concrete structure of a typical residential building in Brazil. To achieve the proposed objectives, a SCC mix was developed in the laboratory and tests were performed in the fresh and hardened states. Two floors, consisting of columns, beams and slabs, were built with SCC and a third with PCC. Pouring time and its generated noise, appearance of pathological manifestations after pouring, amount of labor required for pouring, costs and the risk of work-related accidents were evaluated. The results indicate that the floors produced with the SCC obtained 60.5% less pouring time, a reduction of 50% and 62.8% in the quantity and costs of labor, respectively; 260.8% reduction in the accident risk factor and, finally, a reduction of 56.4% in the total cost.
DOI: 10.6084/m9.figshare.14307291
title: Ultrasonic investigation on the effectiveness of crack repair in concrete

description: abstract: The crack injection technique using epoxy systems is usually performed in the services of rehabilitation of surface cracks in concrete structures. The evaluation of the injection process can be done by the removal of cores, which is a destructive test not able to evaluate the entire structure. Alternatively, the use of nondestructive testing, specifically those based on the propagation of stress waves can provide information on the effectiveness of injection services. Even though the time-of-flight technique which provides the ultrasonic pulse velocity is the most common parameter used in concrete evaluation, the ultrasound waveform energy-related parameters can be used to indicate if crack was fully filled. The energy of the ultrasound signal depends on the propagated travel path, which differs when the crack is not filled. This paper presents the results of an experimental program with artificial surface cracks filled with epoxy in different depth fractions. Two types of epoxy were used. It was observed that the ultrasound waveform energy-parameters were able to detect repair effectiveness.
DOI: 10.6084/m9.figshare.14307290
title: Numerical analysis on displacements of steel-fiber-reinforced concrete beams

description: abstract: This work deals with parametric analyses of the structural behaviour of steel-fiber-reinforced concrete using a Damage Constitutive Model and homogenization technique. This approach is contemporary once Brazil has not a standard procedure for the design of this type of material. The present study performs a parametric analysis of rectangular beams subjected to flexion at four points, with height variations (h), reinforcement area (As) and span (L) are used to verify the influence of each parameter on the numerical study of the deformability of beams composed by this material. Fiber volume concentrations of 2.00% and 2.50% have been used on the modelling. It is observed that the obtained results were mainly affected by height and span. It is noticeable that the inclusion of steel fibers leads to an increase in the maximum load and ductility of the analyzed beams in this work.
DOI: 10.6084/m9.figshare.14307288
title: Parametric study of the strength of reinforced concrete polygonal sections submitted to oblique composite flexion

description: abstract: This work aims to verify the influence of characteristic compressive cylinder strength ( f c k), section geometry and eccentric axial load on the strength of square, cross, “T” and “L” reinforced concrete sections, under oblique composite flexion. A computational algorithm was created to calculate sections interaction diagram of bending strength, taking into account NBR 6118 idealized parabola-rectangle stress-strain relationships for 20 to 90 MPa f c k concretes. The results show that f c k influence is stronger for higher values of axial load and that the failure surface shape in interaction diagrams depends directly on the f c k and on the rebars distribution in the section. Furthermore, under lower compressive axial loads, higher oblique composite flexion strengths are reached when there is more reinforcement area in tension regions but, as the compression increases, the reinforcement presence and larger concrete areas in compression zones provide higher bending moment strengths.
DOI: 10.6084/m9.figshare.14307287
title: Numerical analysis of composite steel and concrete beams subjected to fire under different support conditions

description: abstract: To evaluate the behavior of semi-continuous composite beams in fire, six finite elements numerical models with several steel profiles and slab dimensions were developed in ABAQUS software. The models took into account several behaviors usually suppressed in simplified analyzes such as: geometric and materials non-linearity properties and thermal expansion effects, including indirect stresses. Three support conditions were analyzed: simply supported (axial released), axial restrained and semi-continuous, totaling 18 analyzes. The different support conditions results were compared to each other and to the fire resistance time designed by simplified methods, which followed design code recommendations.
DOI: 10.6084/m9.figshare.14307285
title: Study of the influence of jigging of recycled coarse aggregate on the compressive strength of concrete

description: ABSTRACT: The composition heterogeneity of this type of aggregate is indicated as one of the main restrictions to its potential utilization since it generates great variability in the performance of the types of concrete produced with recycled aggregate. To reduce the use limitations of recycled coarse aggregate (RCA), this study aimed to analyze the use of a jig, a type of equipment used in mining, which performs density separation through air sprinkling in the selection of large aggregates of CDW crushing. To evaluate the equipment performance in the selection of RCA materials, specimens of concrete with recycled aggregate of three different sources were molded before and after selection in the jig, as well as reference concrete with natural aggregate. To measure the performance of the types of concrete produced, axial compressive strength tests were performed. Additionally, a statistical and comparative analysis of the results was performed to seek a better basis for possible conclusions. Analysis of the results of the axial compression strength tests showed that the variability of the recycled aggregates reflected in the inconstancy of the behavior of the concrete produced with them; it was not possible to perceive a common or uniform performance between the three sources of recycled aggregate for the mix design produced. Although some studies point to good separation results with jigging, it was found that with the use of recycled aggregates available in the local market, for the three studied sources, the selection was not able to minimize the variability of the properties of the recycled types of concrete produced with the selected aggregates.
DOI: 10.6084/m9.figshare.14307284
title: Nonlinear analysis of monolithic beam-column connections for reinforced concrete frames

description: abstract: This paper deals with nonlinear analysis of deformability of monolithic beam-column connections for bending moments in framed reinforced concrete structures. Due to the simplicity, the connections deformability is considered by using an analytical model of moment-rotation curve. Material nonlinearity of the structural elements is considered by using the flexural stiffness obtained in moment-curvature relationship of the sections. The formulation of the analytical model to obtain the relative rotations between beam and column and the formulation to construct moment-curvature curves is deduced and presented to allow the computational implementation in structural analysis software. The numerical simulations carried out in this study indicated that even in the case of monolithic connections, taking into account the bending moment deformability of the connections leads to significantly better results than the hypothesis of fully rigid connections.
DOI: 10.6084/m9.figshare.14307282
title: Numerical simulation of steel-concrete composite beams: updated strategies of finite element modeling

description: abstract: The use of steel-concrete composite beams allows the best properties of these materials to be explored, resulting in more economical solutions. Many researchers have studied the behavior of composite beams from different strategies of numerical modeling, and some of these are presented in this article. In this context, the present work proposes the construction of a tridimensional numerical model using ANSYS software, version 19.2, with current-technology elements and compatible material models. For the simulation of concrete behavior, two models have been used: the first, denominated DP-CONCRETE, is a native ANSYS model, available in the more recent versions of this software; and the second, denominated USERMAT, is a customizable model that was developed based on Ottosen criterion. The results obtained with these models for the analyzed beams presented a good correlation with the experimental results and with numerical results from previous works.