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It is notable that brick work structures endure a lot of harm during seismic tremors, prompting huge loss of lives. Practically 75% of the disaster, credited to seismic tremor in a century ago, is because of breakdown of workmanship structures [1] . A greater part of the apartments in India are Unreinforced Masonry (URM) structures that are powerless and helpless much under moderate quakes and due to high wind forces out-of-plane action is acting on the wall which makes a severe damage at high wind loads and it is well known that Reinforced masonry construction has got a significant number of advantages than the masonry without reinforcement, whose application is very less in Indian construction practices and still there are no specified codes prescribed and in most constructions there been used shear walls instead of reinforced masonry walls even at the moderate earthquakes [2] . On the other hand, a great need to focus on understanding masonry buildings that are subjected to both axial loaded and seismic loads [3] . The main objective of this paper is to study the methods available in the literature to obtain the seismic vulnerability of un-reinforced masonry walls using linear static analysis [4] . To achieve this, analysis (Staad.Pro software) have been carried out as a part of this research. Two walls with same dimensions with an unreinforced and bed type reinforced masonry were analysed under uniaxial loading. A constant axial compressive load was maintained for each specimen during the analysis [5] . Idealized Load vs Deflection plots are used to describe the wall deflections and maximum stresses evolved by using STAAD.Pro. The final outcome of this performance analysis declares the efficiency of Reinforced masonry walls over the masonry walls without reinforcement under both axial and seismic loads (Load vs Maximum shear stress).

Waste management includes storage and environmental issues, as well as waste generated from recycled particles. Utilization of waste materials leads to reduce cost of material and also helps an environment friendly eco-system. An attempt was made to develop titanium-based hybrid composites using modified pressure crystallization processes using different weight fractions. This research focused on using agro-waste and solid-waste particles as reinforcement materials with Ti64 as a matrix to minimize the cost of material widely utilized in the medical and industrial sectors. The hypothesis of this work is to examine the mechanical properties and hot deformation behavior by varying five different temperatures (800–1000 °C) and strain rates (0.01–10 s−1) using a 150 Ton universal testing machine. The processing maps for safe and unsafe domains during heat treatment have been recognized. Surface morphology and phase distribution are performed. The Ti64/7.5% (SiO2–PKSA) hybrid composite shows low porosity and superior strength.

The paper presents a new methodology to model material failure, in two-dimensional reinforced concrete members, using the Continuum Strong Discontinuity Approach (CSDA). The mixture theory is used as the methodological approach to model reinforced concrete as a composite material, constituted by a plain concrete matrix reinforced with two embedded orthogonal long fiber bundles (rebars). Matrix failure is modeled on the basis of a continuum damage model, equipped with strain softening, whereas the rebars effects are modeled by means of phenomenological constitutive models devised to reproduce the axial non-linear behavior, as well as the bond–slip and dowel effects. The proposed methodology extends the fundamental ingredients of the standard Strong Discontinuity Approach, and the embedded discontinuity finite element formulations, in homogeneous materials, to matrix/fiber composite materials, as reinforced concrete. The specific aspects of the material failure modeling for those composites are also addressed. A number of available experimental tests are reproduced in order to illustrate the feasibility of the proposed methodology. Fil: Oliver, J.. Universidad Politecnica de Catalunya; España Fil: Linero, D.L.. Universidad Nacional de Colombia; Colombia Fil: Huespe, Alfredo Edmundo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo Tecnológico para la Industria Química. Universidad Nacional del Litoral. Instituto de Desarrollo Tecnológico para la Industria Química; Argentina Fil: Manzoli, O.. Universidade de Sao Paulo; Brasil

Corrosion-induced deterioration of reinforced concrete (RC) structures results in premature failure of the RC structures. In practice concrete crack width is one of the most important criteria for the assessment of the serviceability of RC structures. It is therefore desirable to predict the growth of the crack width over time so that better informed decisions can be made concerning the repairs due to concrete cracking. Literature review shows that little research has been undertaken on numerical prediction of concrete crack width. The intention of this study was to develop a numerical method to predict concrete crack width for corrosion-affected concrete structures. A cohesive crack model for concrete is implemented in the numerical formulation to simulate crack initiation and propagation in concrete. Choices for evaluating the parameters of cohesive elements are extensively discussed which is a key for developing a plausible model employing cohesive elements. The surface crack width is obtained as a function of service time. Accurate prediction of crack width can allow timely maintenance which prolongs the service life of the reinforced concrete structures.

The present paper deals with the of Rayleigh surface waves in fiber-reinforced solid anisotropic magneto-thermo-viscoelastic media, a pre-stressed elastic layer of finite thickness over a h...

This paper presents a test of cast-in anchors in the plastic hinge zone of a reinforced concrete column. Design codes, such as ACI 318-11, do not allow concrete anchors in concrete that could be substantially damaged during an earthquake unless special reinforcement is provided. Steel reinforcement has been proven effective in protecting core concrete; however, it does not protect cover concrete, which is critical to the shear behavior of anchors. Fiber reinforced polymer (FRP) composite material was used in this study to protect cover concrete around the test anchors. The column specimens were subjected to quasi-static cyclic loading while the single anchors were loaded in cyclic shear. Compared with the anchors in unprotected concrete, the FRP reinforced anchors developed a higher shear capacity at a much smaller displacement. This indicates that FRP fabrics can be effective as external reinforcement for concrete anchors. Meanwhile, a systematic study is needed before practical applications.

Limit analysis, a general and powerful method to predict the collapse load of reinforced concrete slabs, combines the limit theorems of classical plasticity with numerical methods, and results in an optimization problem. The number of variables in the corresponding optimization problem depends on the number of degrees of freedom used per node. In this paper, a rotation-free meshfree method based on integrated radial basis functions (iRBF) is developed. There is no rotational degree of freedom involved in the approximation, and hence the size of the resultant optimization problem is kept to a minimum. Moreover, the iRBF based shape functions hold the Kronecker delta property, ensuring that there is no need for any special treatment when enforcing essential boundary conditions. The obtained discrete kinematic formulation is handled using available highly efficient solvers. Various Nielsen’s reinforced concrete slabs of arbitrary geometries are examined, showing that the proposed numerical procedure is capable of providing accurate collapse load multipliers and automatically identifying yield-patterns in terms of plastic dissipation distribution.

The way to strengthen concrete structures in civil engineering by adding external reinforcement using carbon fiber composites is widely spreading in recent years. A method for calculating the strength of reinforced concrete in hydro technical constructions with reinforcing by carbon fiber composite materials was invented with the aim to justify the solutions of strengthening concrete structures. It was taken into consideration that the characteristic features of mass reinforced concrete structure with sand operating loads which including backpressure of water in the cracks and in opened construction joints. It has evolved the relations for calculation of strength in normal cross section of bending reinforced concrete member of hydro technical constructions which strengthening with external reinforcement by carbon fiber.

The results of experimental studies of reinforced concrete constructions at complex resistance to torsion with bending are shown in the article. The main purposes of the researches are detection of regularities and determination of deformation and cracking parameters. The most important of the studding parameters are cracking load, destructive load, the coordinates of spatial cracks formation, the width of crack's opening at the axis of the longitudinal and transverse tensile reinforcement and along the entire profile of cracks; changing the distance be- tween the cracks and crack length according to increasing the deformation load; deformation of compressed concrete and reinforcement in a complex stress-strain state. The test results are presented in the form of relationships of structure's deflections, deformations of compressed concrete and reinforcement, including results which were determined by the indications of electrotensometric sockets. The obtained relationships allow us to assess the reliability of the calculating methods reinforced concrete constructions subjected the action torsion and bend- ing.

International audience; The durability of reinforced concrete structures is largely impacted by their transfer properties, which can be evaluated through, for example, permeability measurement. Usually, concrete permeability is studied on plain specimens and the effect of the presence of steel bars on permeability in reinforced concrete has been little studied in the literature. The steel-concrete interface presents a larger porosity than plain concrete, which can be the cause of preferential percolation paths for fluids. Such percolation paths could create a lower resistance to fluid transfer and modify transfer kinetics. For reinforced and prestressed structures with large reinforcement contents, such as found in nuclear power plants, the impact of the reinforcement on gas transfer should be identified to obtain a better assessment of the flow within the structure. The aim of this experimental study is to characterize the effect of the presence of reinforcement on such flows by measuring leakage rates, permeability, and time to reach the steady state. Measurements were performed with a Cembureau constant head permeameter on cylindrical concrete specimens with or without steel bars. Since gas transfer into concrete depends on the rate of saturation of the material, the specimens were tested at different degrees of saturation: 0%, 6%, 30%, 60%, 80%, 90% and 100%. The analysis quantifies the impact of the defects created by the steel bar for each state. The results show that material composed of concrete and reinforcement can be divided into two distinct permeability zones: the plain concrete and the steel - concrete interface with or without cracking. These two zones can be associated in series and/or in parallel according to the configuration. The consequences on permeability measurement in reinforced structures are discussed.

The dramatic increase in computation efficiency over the last three decades has made the finite-element simulation approach the dominant tool for investigating blast phenomena and their effects on building structures. However, the simulation results depend greatly on the mesh size selected for the numerical model, which may generate an inaccuracy in predicting the phenomena correctly. Thus, mesh size for finite-element simulations, appears to be an epistemic uncertainty that is inherent to the simulation process. This paper investigates the reliability of finite-element simulations of a reinforced concrete slab subjected to a certain level of explosion, in terms of mesh size sensitivity. Full-scale free air blast experiments are performed to monitor the blast-structure interaction phenomenon and help validating the numerical simulations. Fifteen finite-element simulations are evaluated with coarse to fine range mesh sizes, and the effects of mesh resolution on the numerical simulations are analyzed. An optimum mesh size is determined for a given set of loading conditions, and established by the amount of internal energy that gives rise to the expected damage on the slab.

Corrosion of reinforcement reduces the load carrying capacity, energy dissipation and ductility of Reinforced Concrete (RC) members. In the present study, reinforcements of RC beam are subjected to 10, 25, and 30% corrosion and the respective RC beams are tested to evaluate their ultimate load behaviour. A huge drop in energy dissipation capacity of the RC beam is observed beyond the corrosion level of 10%. Further, nonlinear finite element analysis is employed to assess the load–displacement behaviour and ultimate load of RC beam. The corrosion induced damage to the reinforcement is represented in the finite element model by modifying its mechanical properties based on the results reported in the literature. The resultant load versus displacement curves of reinforced concrete beams are obtained. Good correlation is observed between the finite element analysis results and that obtained from experimental investigation on the control beam. The experimental results are also compared with the finite element analysis results for RC beams with corroded reinforcement. In order to understand the effect of corrosion on the mechanical properties of reinforcement, the corroded reinforcements are modelled in nonlinear finite element analysis by (i) reducing the area of reinforcement alone (ii) by reducing both area and mechanical properties and (iii) reducing the mechanical properties without reducing the area of steel as reported in literature. The results obtained for the beam with corroded reinforcement confirms reduction in yield stress and ultimate stress of the reinforcement steel.

This paper focuses on the relationship between the shear capacity and the flexural cracking load of Fiber Reinforced Polymer (FRP) reinforced concrete beams without stirrups. A relationship between the cracking load that causes a beam to crack at the middle of shear span and the shear capacity of the beam is confirmed based on the test results of 29 beams. The relationship was further examined by comparing the test results of 168 FRP reinforced beams and one-way slabs that were collected from literature. All specimens were reinforced in the longitudinal direction only and tested as simply supported conditions subjected to 4-point bending. The concrete compressive strength, reinforcement ratio, shear span-to-depth ratio, and effective depth of the beams in the database were in the range of 24.1–88.3 MPa, 0.12–2.63%, 1.1–6.45, and 141–1111 mm, respectively. The comparison revealed that there is a strong relationship between the cracking loads and the shear capacity of the members. This relationship can be used to develop a shear design method for FRP reinforced members.

Under the effect of the ascending loading, the behavior of reinforced concrete structures is rather non linear. Research in industry and science aims to extend forward the use of non-linear calculation of fiber concrete for structural parts such as columns, veils and pious, as the fiber concrete is more ductile behavior then the classical concrete behavior. The formulation of the element has been established for modeling the nonlinear behavior of elastic structures in three dimensions, based on the displacement method. For the behavior of concrete and fiber concrete compressive and tensile strength (stress-strain) the uniaxial formulation is used. For steel bi-linear relationship is used. The approach is based on the discretization of the cross section trapezoidal tables. Forming the stiffness matrix of the section, the integral of the surface is calculated as the sum of the integrals on each of the cutting trapezoids. To integrate on the trapeze we have adopted the type of Simpson integration scheme.

Over the last few years externally bonded carbon fiber reinforced polymer (CFRP) laminates have become a popular technique for retrofitting reinforced concrete (RC) existing structures. This paper presents an experimental study on 10 RC members externally reinforced with different architectures of CFRP laminates in order to investigate the influence of the composite configurations on the structural behavior of RC members. American guidelines ACI 440.2R and Italian Code CNR-DT 200 are employed for comparison with the experimental results. Numerical models are also developed to simulate the behavior of the FRP-RC members with the aim to investigate the different failure modes observed in various strengthening configurations. One conclusion is that the Italian Code CNR-DT 200 results to be more conservative with respect to ACI 440.2R. Finite element analyses provide good predictions of the experimental evidences in terms of load-deflection, load strain diagrams, and crack distribution and lead to an accurate prediction of the debonding failure and the post-failure response.

In order to investigate the shear behavior of the new and old concrete interface, three kinds of reinforced concrete models with new-old concrete anchorage reinforcement were designed and fabricated. The semi-cyclic loading test was carried out. The failure mode, shear bearing capacity, interfacial shear slip and stress distribution of steel bars were analyzed. The test results show that the failure mode of the old and new concrete reinforcement at the interface was split type shear failure. The shear bearing capacity of reinforced concrete is mainly related to the shear resistance of concrete and the dowel pin shear, and the maximum value is about 1.186 × 104 kN/m2. The shear bearing capacity of stirrups reinforced concrete is increased by 28.5%. According to the obvious interface slip, the working state of the interface between rebar bolt and concrete can be divided into the stage of interface bonding and the stage of the friction. The lower part of the tendons is mainly cut and its upper part is shear-based. The largest stress is obtained at the interface and it decreases gradually to both ends. By analyzing the test results and relevant research, the formulas for calculating the shear capacity of the new and old concrete interface are derived. The results show that the formula of shear capacity is correct and feasible.

The importance of cracks, crack width and load carrying capacity of reinforced concrete member subjected to flexural load is so vital and is considered as a very important parameter under serviceability limit state design of concrete elements. The post-crack behavior of a structural member is a measure of its toughness, a vital parameter often used in evaluating the durability of structural element. Steel have been in used as reinforcements in structural members because of its good properties on high tensile stress, ability to improve the toughness of structural members and its durability in concrete environment. However, steel is now very expensive, hence the need for substantive alternative material. Fanpalm is one of the locally available and has been studied as a suitable alternative to steel reinforcements. The study of the cracks and cracks’ patterns with the respect to the sustained loads for concrete slabs reinforced with fanpalm is the concern of this study. Fanpalm specimens were cut, shaped to desired flexural reinforcements sizes. Then used as reinforcements for concrete slabs of 1:2:4 mix and cured in water for 28 days. Flexural strength tests were carried out to evaluate the load causing the first visible crack and the load causing full development of yield lines of fanpalm reinforcement concrete slabs were observed. The theoretical yield loads were lower compared with the observed experimental yielding loads. The results reveal that the cracks increase with increased in load. As the load systematically increases there is another sudden change in deflection at yield points. The highest percentage reinforcement 72%and 65% on y and x plane respectively occurred on slab SLF2 with corresponding value of 16.20 kN and 29.35 kN at first crack and yield point respectively.

Tubular reinforced concrete columns of air-cooling condenser structures, which undertake the most weight of air cooling equipment, are the major components to resist lateral forces under earthquake. Once collapsed, huge casualties and economic loss would be caused. Thus, four 1/8 scaled specimens were fabricated and tested through the pseudo-static testing method. Failure modes and crack patterns of the specimens under cyclic loading were observed. Then, finite element models of tubular reinforced concrete columns were established using OpenSees and were verified with the experimental results. Finally, the influence of axial compression ratio and longitudinal reinforcement on energy dissipation capacity and stiffness degradation were studied based on the validated finite element modes. It is confirmed that tubular reinforced concrete columns of air-cooling condenser structure exhibit a moderate ability of energy dissipation, and the nonlinear finite element model could reasonably simulate its seismic behavior. Furthermore, axial compression ratio and longitudinal reinforcement are main factors which affect the seismic behavior of the tubular reinforced concrete columns. The experimental results and simulation method provide an available way to design this kind of large tubular reinforced concrete columns with thin-wall.

Research is limited with respect to load-deflection behavior of slender concrete columns internally reinforced with Fiber Reinforced Polymer (FRP) spirals and longitudinal bars. An analytical buckling model based on numerical integration is presented to predict the load versus deflection performance of slender concrete columns reinforced with FRP spirals and longitudinal bars, subjected to eccentric loads. The model can be used to predict the behavior of slender concrete columns with various configurations including FRP and/or steel reinforcement, single or double spiral, and number of longitudinal bars. The longitudinal bars considered include steel, FRP, or hybrid reinforcement consisting of steel and FRP bars. The model is found to predict the experimental performance of slender concrete columns reinforced with Glass FRP longitudinal bars and spirals with satisfactory accuracy. The model is used to create interaction diagrams for FRP spiral-confined circular concrete columns with various slenderness ratios, reinforced with steel, FRP or hybrid reinforcement.

Glass fiber reinforced polymer (GFRP) bars are emerging as desirable alternatives for traditional steel reinforcements in concrete industry. A proper bond between concrete and reinforcement is critical for the performance of reinforced concrete structures. Due to the complexity of modeling the bond action, a perfect bond has been usually considered with the slippage between concrete and reinforcement neglected. The purpose of the present study is to develop a parametric bond-slip model based on pull-out tests performed on sand coated GFRP bars. It included exponential rising, linear descending and residual constant bond stress stages. A sensitivity analysis was performed to determine the bond parameters. Different points along the embedded length of the bar were monitored to illustrate the difference between the average and nodal bond-slip relationships. The proposed bond model was used in a finite element analysis that modeled the cracking in concrete and explicitly simulated the bond action. The model was capable of presenting both concrete splitting and pull-through modes of failure. Simulations were performed on samples with different concrete covers to demonstrate both failure modes.

This article has been retracted at the request of the Editor-in-Chief due to extended similarites with a previously published paper (in Persian).The previously published paper is:F. Jafari, J. Akbari, A. Jahanpur, "Evaluation of Safety Index and Calibration of Load and Resistance Factors for Reinforced Concrete Beams under Bending, Shear and Torsion Demands", Journal of Structural and Contruction Engineering, Article 5, Vol. 3, No. 4, pp. 49-64, 2017 (in Persian)The authors of this paper failed to provide any reasoning regarding the case.

The data presented in this article are related to the research article entitled “Experimental Investigation of cracking and deformations of concrete ties reinforced with multiple bars” (Rimkus and Gribniak, 2017) [1]. The article provides data on deformation and cracking behaviour of 22 concrete ties reinforced with multiple bars. The number and diameter of the steel bars vary from 4 to 16 and from 5 mm to 14 mm, respectively. Two different covers (30 mm and 50 mm) are considered as well. The test recordings include average stains of the reinforcement and the concrete surface, the mean and maximum crack spacing, final crack patterns, and crack development schemes obtained using digital image correlation (DIC) system. The reported original data set is made publicity available for ensuring critical or extended analyses. Keywords: Reinforced concrete, Multiple bars, Tensile tests, Deformations, Cracking

The reinforced concrete beams is a structural member that is widely used in all types of building and civil constructions. These beams are subjected to different external loads that, above a critical value, may cause the collapse of the whole structure, having devastating consequences for civilians. Therefore, the a priori simulation of the internal forces developed within a reinforced concrete beam, when it is subjected to external loads, is mandatory to figure out its progressive structural response, to provide integrated risk assessment for a wide range of constructions such as buildings, bridges, etc. In this paper, we provide a simulation framework to estimate the behavior of reinforced concrete beams when they are subjected to external loads. Of particular interest to us is the simulation of the particularly damaging internal force, called Shear force. Several techniques are under study such as regression analysis, Little Genetic Algorithm (LGA) and Covariance Matrix Adaptation Evolution Strategy (CMA-ES), along with different objective functions (lineal, polynomial and rational functions) to provide a solution that satisfies both the physical and computational constraints of the targeted problem. These techniques are empirically optimized by using different parameters and genetic operators such as elitism, penalization for unfeasible individuals, crossing by one point or by linear combination of two individuals, mutation by gen or by individual. Numerical results reveal that CMA-ES algorithm together with a proper objective function, elitism and penalization allows predicting, under a relative error less than 5% (compared to experimental data taken from a tested beam), the shear response of a reinforced concrete beam in the stages near to the structural collapse.

Fiber-reinforced polymer bars are gaining increased use in the construction market as a replacement to steel reinforcement for concrete structures. However their use as compression members is limited due to their mechanical properties, typically low flexural rigidity, so that local buckling may occur relatively at low stress levels. Their premature rupture in reinforced concrete (RC) columns could be eliminated by enhancing the columns’ response elastically and concentrating damage to the externally installed, replaceable post-tensioned structural fuses. This paper is part of a larger numerical and experimental investigation to develop and validate design methods for a rocking aramid fiber reinforced polymer (AFRP) reinforced concrete column. The numerical study, implemented using the Extreme Loading for Structures software, consists of a total of thirteen columns. The columns were subjected to axial load followed by cyclic lateral load up to failure to examine the effectiveness of the rocking con...

In 1967–1985, a research campaign comprising a unique set of long-term experimental data on concrete beams was conducted in joint collaboration with four Belgian research institutes to determine the influence of creep and shrinkage on the long-term behavior of reinforced concrete members. The main aim of the research campaign was the determination of the long-term behavior of cracking and deformations subjected to permanent loads considering the influence of the magnitude of the loads and various reinforcement ratios. The objective of this article is twofold: to provide an overview of the measured data of the reinforced beams of the research campaign, which has never been published before, and to propose a simplified calculation method based on available models in literature that can predict the available measurement data. A simplified calculation model is proposed, which accounts for nonlinear creep strains due to high stresses, shrinkage, aging, and cracking in reinforced concrete beams. This numerical method is based on a cross-sectional analysis formulated using the layered Euler-Bernoulli beam theory, allowing fast and accurate predictions of strains, stresses, and deflections as a function of time based on fib Model Code 2010 and EN1992-1-1. The measurements of the beams subjected to high permanent loads during a time period of 4 years are compared to the results evaluated with the proposed simplified calculation model. The results show that the proposed simplified calculation method based on the current models of EN1992-1-1 and fib Model Code 2010 can predict the long-term behavior of reinforced concrete beams subjected to high loads in good agreement with the measurements.

The influence of temperature induced bond degradation on response of reinforced concrete (RC) beams exposed to fire is presented. A finite element based numerical model is developed in ABAQUS for tracing the response of reinforced concrete beams exposed to fire. Temperature induced interfacial bond degradation between concrete and reinforcing steel is specifically taken into account using bond-link element approach. The effect of temperature dependent local bond stress-slip relations on fire resistance of both normal strength and high strength reinforced concrete beams is investigated. A comparison of numerical model predictions with response parameters measured in fire tests clearly indicate that interfacial bond between reinforcing steel and concrete can influence extent of strength degradation and deflections in RC beams exposed to fire leading to relatively lower fire resistance in the beams. Hence, the current approach of assuming a perfect bond between rebar and concrete in fire resistance analysis of reinforced concrete structures may be un-conservative in certain scenarios, especially for RC beams reinforced with smooth rebars and when rebar temperature exceeds 400 °C.

In recent years, fiber-reinforced polymer (FRP) bars have been used as novel concrete reinforcement in the beams. However, the ductility of the beams is highly dependent on the properties of concrete since concrete crushing governs the failure mode. Substitution of concrete with engineered cementitious composite (ECC) can avoid the cracking and durability problems associated with brittleness of concrete. In this paper, the flexural behavior of ECC and concrete beams reinforced with basalt FRP bars were numerically investigated with the software of ATENA/GID solver. To verify the validity of the finite element models of the composite beams, the simulation results were compared with the published experimental results of both FRP reinforced concrete and ECC beams, and good agreements were achieved. According to the simulation results, the BFRP reinforced ECC beams show much better flexural properties in terms of load-carrying capacity, deformability and crack controlling ability compared with the BFRP reinforced concrete beams. Also, the BFRP bars in ECC matrix were much more efficiently utilized than those in concrete, and the failure process is much more ductile due to much higher ultimate compressive strain of ECC materials in the compressive zone. An extensive parametric analysis was then conducted to examine the effect of various parameters on the flexural behavior of BFRP reinforced ECC beams.

Recent experimental results have shown that current minimum vertical reinforcement limits in many concrete design standards are insufficient to ensure that large ductility can be achieved during earthquakes. A detailed finite element model was developed in VecTor2 to provide a tool for further investigating the seismic behaviour of lightly reinforced concrete (RC) walls. The model was verified using experimental data from recent RC wall tests with minimum vertical reinforcement, and was shown to accurately capture both the overall response and local response parameters with good accuracy such as the cyclic hysteresis response, crack pattern, and vertical reinforcement strains. The model could also be used to estimate the drifts at which reinforcement buckling initiated and when reinforcement fractured occurred. The results from additional analyses showed that a potential size effect exists when considering the failure of lightly reinforced concrete walls. When keeping the reinforcement ratio and shear span ratio constant, the lateral drift capacity decreased significantly as the wall length increased. Using reinforcement with higher strength and lower ductility did not significantly impact the crack pattern, but did decrease the lateral drift capacity of the walls. Furthermore, reducing the strain hardening ratio of the reinforcement, or increasing the concrete strength, both resulted in a reduction in secondary cracking in the plastic hinge region and a reduced lateral drift capacity. It is recommended that wall length and average material properties should be accounted for when assessing the seismic behaviour of lightly reinforced concrete walls or when developing design standard requirements.

The article discusses a problem of the crack length influence on the reliability (safety) of reinforced concrete beams under conditions of limited statistical information about controlled parameters in the design mathematical models of limit state. Numerical examples revealed the possibility of practical application of the reliability analysis methods for inspections and determining the category of the technical condition of buildings and structures. The article offers the methods for reliability (probability of non-failure) analysis and the residual resource of reinforced concrete beams according to the criterion of the normal crack length in the tensile zone of reinforced concrete beams. The methods of reliability analysis constructed on the basis of possibility theory and fuzzy set theory. The algorithms of reliability analysis of reinforced concrete beams are presented on numerical examples of reliability analysis.

The aim of the paper is a nonlinear analysis of concrete structures. For these type of tasks is an important suitable choice of model input parameters and concrete. Especially if the analysis is preceding the results of an experiment, which can determine the exact properties of concrete. The following properties of concrete are needed for nonlinear analysis: tensile strength and compressive strength of concrete. There are more procedures how to determine some unknown input parameters. The paper presents some approaches to calculating and selecting parameters, which are based primarily on the recommendations of the Model Code and professional articles. Specifically, the numerical analysis performed in our developed program which allows observing a nonlinear behaviour of concrete at loading case.

© 2017 Trans Tech Publications, Switzerland. This study presents the analysis of the constitutive behavior of fiber-reinforced polymer (FRP)-confined steel fiber reinforced concrete (SFRC) using a newly developed concrete damage-plasticity approach. Finite element (FE) analysis is conducted based on Lubliner's model. The new concrete damage-plasticity approach accurately incorporates the effects of the steel fiber volume fraction and aspect ratio, confinement level, concrete strength, and nonlinear dilation behavior of confined concrete. New failure surface and flow rule were established using the experimental database. In order to validate the damage-plasticity model, the predictions from the FE analysis are compared with both experimental results and predictions of an accurate existing model for FRP-confined plain concrete. The analysis results indicate that the proposed approach accurately predicts the compressive behavior of FRP-confined SFRC.

Steel frames with reinforced concrete infill walls (SRCW) are an interesting seismic-resistant structural solution. However, an effective seismic design of SRCWs is not easy due to the current lack of specific capacity design rules that allow controlling the formation of a proper energy dissipating mechanism. In order to overcome such an issue, a ductile design procedure is presented in this paper. The proposed procedure leads to innovative SRCW systems where energy dissipation is expected to take place only in the vertical elements of the steel frame, which are subjected mainly to axial forces. The non-ductile components, i.e. reinforced concrete wall and steel-to-concrete connections, are expected to suffer negligible damage. Accordingly, the system is designed to control the formation of diagonal struts in the infill walls and behaves as a lattice brace instead of a shear wall. Experimental test results and nonlinear finite element analyses are illustrated to support the developed ductile design approach and highlight the advantages of SRCWs.

In this paper the response of a reinforced concrete slab to a time variable load is presented. The time course of loading is in the first phase defined by a linearly increasing function and in the second phase by a constant function. The response is solved by a modified method of matrix functions.

Using capacity spectrum method was analyzed frame reinforced concrete structures. Capacity spectrum method has been used to analyse frame reinforced concrete structures. Geometry, material properties and reinforced cross sections were designed by experimental tested model of reinforced concrete frame joints in the scale of 1:1. The results were compared with the results of the analysis of the structure of the same geometrical characteristics but of standard material properties of concrete and steel.

For the composite structure comprised of steel-lined concrete, the inside steel liner and surrounding reinforced concrete are designed to work reliably. The potential sliding between the reinforced concrete and steel liner has a significant effect on the structure bearing mechanism. The Coulomb friction model is employed to simulate the sliding of the steel liner against the surrounding concrete. A concrete damage plasticity (CDP) model is proposed to simulate the surrounding reinforced concrete. The finite element (FE) models of the steel-lined reinforced concrete penstock (SLRCP) located on the downstream surface of a double curvature arch concrete dam are developed, in which the nodes-shared method (NSM) and the friction-contact method (FCM), respectively, are employed. The concrete crack initiation time, concrete crack propagation pattern, penstock deformation, tensile stresses of the steel liner and the reinforcements are presented. The results of the FCM model agree well with the monitoring data, validating that the proposed model could be directly employed in the FE software ABAQUS.

Understanding the development and multiaxial distribution of expansions is of critical importance in the appraisal of structures affected by alkali–silica reaction. Such expansions were monitored for 33 480-mm reinforced concrete cubes in an effort to develop an improved understanding of the expansion mechanisms in reinforced concrete and broaden the database of experimental results available from which to build tools to aid in the performance assessment of affected structures. The cubes were fabricated using three different concrete mixtures of varying reactivity and contained uniaxial, biaxial, and triaxial reinforcement layouts with different reinforcement ratio combinations. In all cases, the cubes expanded at greater rates in unreinforced directions than in reinforced directions. Furthermore, the reinforcement ratios did not significantly influence expansion behavior, especially in the cases of uniaxially, equal biaxially, and equal triaxially reinforced specimens. Increasing the number of reinforced directions resulted in reduced volumetric expansion development over time and greater differences between expansions in reinforced and unreinforced directions. Cubes with end-anchored, deformed steel reinforcing bars placed in three layers developed expansions exceeding steel yield strains in all directions. Cubes with bars placed in two layers exhibited differential expansions between locally reinforced concrete regions at the edges of elements and unreinforced core regions. Mixture reactivity and environmental conditioning influenced expansion rates but not trends of the multiaxial distribution of volumetric expansions.

The steel fibre reinforced concrete is expensive compared with the ordinary concrete. The costs for the production, the transport and the setting of steel fibre reinforced concrete should be directly proportional to its quality. The quality of material can be quantified in a broad spectrum of properties (the workability, the mechanical and physical properties, the durability, etc.). This article is focused on the influence of mechanical and physical properties (the tensile strength and the residual tensile strength) on ULS and SLS. The paper is limited only to the bending load bearing capacity from ULS point of view and limited only to vertical deformation from SLS point of view. The example is a part of paper – the calculation of two bending structures. Firstly, it is calculated as the structure of ordinary reinforced concrete and secondly it is calculated as the structure of reinforced steel fibre reinforced concrete. The geometric arrangement, the type and the quantity of reinforcement are identical for both calculated structures. The calculated structures are different only in the tensile strength and the residual tensile strength. All other input parameters (including modulus of elasticity) are identical for both calculated structures, in order the influence of tensile strength on ULS and SLS excels. The presented results should be the basic concept for the effectiveness assessment of steel fibre reinforced concrete application.

The use of steel fiber-reinforced concrete (SFRC) for low-rise walls in low-seismicity regions is evaluated experimentally. Shake-table tests of SFRC and conventionally reinforced concrete walls with an aspect ratio of 1.0 under several ground motions to failure were conducted. Main variables studied were fiber aspect ratio (64 and 80) and fiber volume content (0.55%, 0.75%, and 1%). Wall performance is assessed in terms of crack patterns, failure modes, lateral resistance and hysteretic response. The results showed that SFRC walls exhibited superior performance than that observed for the wall with welded wire reinforcement in the web. Furthermore, SFRC walls containing 0.75% or 1% fiber volume content exhibited a response that was as good as that observed for the wall reinforced with deformed bars as web reinforcement in terms of lateral strength and drift capacity.

Advanced composite-encapsulant with reinforced solid inorganic fillers dispersed in the epoxy resin is regarded as a revolutionary effort in promoting the reliability of electronic device. While various researches have been conducted to study the preparation, chemical and thermomechanical properties of composite-encapsulant using filler-reinforcement, there is however no work found on the visualization aspect of the encapsulant flow progression and filler distribution in the encapsulant. In this paper, the underfilling rheology for encapsulation process of ball grid array (BGA) will be investigated using mono-dispersed nano-silica (SiO2) composite-encapsulant. The filler loadings will be varied in the range of 2–25 wt% (weight percent) for optimization purpose. Eventually this work is aimed to provide an in-depth understanding on the impact of the amount of nano-silica fillers being added in the epoxy resin. Finite volume method (FVM) based numerical simulation using discrete phase model (DPM) will be used in this paper. The simulation works reported that the increase in filler loadings of composite-encapsulant effectively lengthen the underfilling process by up to 22% together with a decrease in average encapsulant's pressure. Furthermore, the flow profiles revealed an asymmetry flow front that is prone to form at high filler loadings. This subsequently leads to issues associated to filler's accumulation and swirling. Given these issues, the optimization of filler loadings in composite-encapsulant is of prime importance. Accordingly, this study recommended the usage of 15 wt% of nano-silica composite-encapsulant that balances between the relatively lower filling time and with reduced issues relating to filler accumulation and swirling while preserve the improvement in reliability upon the fillers additive. Additionally, the simulation of dispersed particle in continuous fluid phase using DPM had decisively proven its mettle and is hopefully will pioneer a new viable numerical tool in the nano-filler composite polymer study of electronic packaging in near future.

Reinforcement and repair of reinforced concrete structures is often more economical and sustainable (less cement consumption, less CO 2 production) than reconstruction. Currently, the solution of reinforcement/repair by carbon-epoxy materials applied to outer surfaces of the structures is routinely used. However, these composites have limitations in terms of cost, fire resistance and sustainable development criteria. The textile reinforced concrete (TRC) mineral-based composite is envisaged as an alternative solution that can solve, at least partially, the above drawbacks. This work aims to experimentally assess contributions of the strengthening/repair of slender reinforced concrete beams subjected to bending by applying the TRC composite. In the first approach, the use of TRC composites in the case of the repair/strengthening of tank shells will be evaluated on the basis of slender beams. Twelve reinforced concrete “beams” are tested for quasi-static monotonic loading by bending tests over four points among 10 beams that have been reinforced/repaired by composite materials . Several parameters including two different modes of curing conditions (28 days immersion in water at 20 °C; 28 days left in air at 20 °C, 50 RH), and two different types of configurations of the beams (with and without pre-cracking) have been considered. This study highlights the mechanical performance of TRC in strengthening/repair of the reinforced concrete beams by analysing the changes in global behaviour (e.g., load/deflection, failure mode, flexural rigidity) and local behaviour (e.g., deformation of steel, pattern cracking, the crack opening). Further evaluation of the local behaviour of TRC should be conducted to address the damage mechanism by multi-cracking of the material and changing the opening of the crack located on the face of the composite.