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Existing studies have proved that interfaces between the prefabricated layer and the cast‐in‐place layer significantly affect the static performance of prefabricated concrete structures using the wet connection method, but little has been known about the fatigue performance, especially at high load levels. This study investigated the fatigue behavior of prefabricated composite concrete beams under negative bending moment induced by the high‐stress level cyclic load. Fifteen composite T‐beams with three different designed sections were tested. The failure mode, cracking and deflection behavior, steel strain development, and the new‐old concrete interfacial deformation were recorded and analyzed. It was found that the stress redistribution occurred with the debonding cracks generated at the new‐old concrete interface, causing the degradation of the static and fatigue performance. Setting interfacial shear keys could prevent such debonding failure at static and low cyclic loading levels. Meanwhile, the corresponding mechanisms were verified through cross‐sectional analysis. [ABSTRACT FROM AUTHOR]

The dual‐function retrofitting system that uses the carbon‐fabric reinforced cementitious matrix (C‐FRCM) as both the anode of impressed current cathodic protection (ICCP) system and the structural strengthening (SS) material, that is, an ICCP‐SS system, is investigated. The experimental program mainly focused on the shear behavior of C‐FRCM strengthened reinforced concrete (RC) continuous beam under the dual‐function retrofitting system. The influence of anode polarization on the shear strengthening of RC continuous beams is analyzed. Shear tests were conducted on a total of 14 corroded RC continuous beams to investigate the influence of key parameters, including anode polarization degree of prefabricated C‐FRCM plate, layer of carbon fiber mesh and side‐wrapping. The failure modes, shear capacities, and load‐deflection curves of the shear‐strengthened RC continuous beams are reported. Based on the test results, the applicability of relevant design codes was evaluated and found to provide rather conservative predictions for the shear capacity of the examined C‐FRCM strengthened RC continuous beams. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation into the flexural and cracking behavior of corroded reinforced concrete continuous beams with 11‐month wet–dry cycles strengthened by anodic polarized carbon‐fabric‐reinforced cementitious matrix (C‐FRCM) plates. The failure modes and flexural bearing capacities were discussed. The influences of the layer of carbon fabric mesh and complete carbon fiber‐reinforced polymer (CFRP) wrapping as end anchorage on the strengthening effectiveness were explored. The complete crack development patterns were captured by a digital image correlation system, and the results showed that the C‐FRCM system can provide satisfactory crack width control, as proved by the reduced crack spacing and the maximum crack width. The flexural capacities of the strengthened beams were effectively enhanced and the debonding failure can be eliminated through complete CFRP wrappings. Moreover, the design recommendations were proposed based on the estimation of the crack development as per related design guidelines. [ABSTRACT FROM AUTHOR]

The goal of this study is to propose a robust method for the analysis and design of recycled aggregate reinforced concrete (RAC) beams. For this purpose, a machine‐learning framework, named, GA‐XGBoost was designed. A comprehensive dataset of 276 tests of RAC beams was compiled from available literature for training, validating, and testing the models. The results confirmed that the proposed models can offer a precise tool for failure mode classification and capacity prediction of RAC beams. For the design framework, a Generative Adversarial Network for tabular data was utilized to produce synthetic data. These synthetic data can provide options for the selection of design variables. In this framework, the design variables are selected by specifying the design constraints, the objective function to be optimized, and validating the capacity requirements using the developed GA‐XGBoost models. Lastly, a web application was developed to make the proposed GA‐XGBoost models appropriate for practical design. [ABSTRACT FROM AUTHOR]

Ductility is one of the most important requirements of RC design besides other requirements such as strength and stiffness. In recent years, concrete beams with a large amount of tensile reinforcement ratio (ρ) have been required in large projects, such as high‐rise buildings and bridges. Using high (ρ) increases the strength and stiffness of the beams and leads to a decrease the ductility. This paper aimed to investigate the effect of using steel fibers reinforced concrete (SFRC) layer in compression zone on the flexural behavior of over‐reinforced concrete beams. Partial replacement of concrete with SFRC layer in compression zone was used to avoid the brittle compression failure of concrete. For this purpose, 12 over‐reinforced concrete beams with a span of 1300 mm and a cross‐section of 120 mm × 180 mm were cast and tested under a three‐point loading. The first beam was used as a reference beam and others as strengthened beams using SFRC layer. The effects of thickness and length of strengthening layer, (ρ), volume fractions of steel fibers, and strengthening methods on flexural performance of tested beams were investigated. The flexural capacity, failure modes, crack patterns, load–deflection relationships, load–strain relationships, ductility index, and toughness were evaluated. The results showed that the suggested technique (SFRC layer in the compression zone) is an effective technique to increase ultimate load, ductility, and toughness by up to 35.72%, 121.01%, and 349.16%, respectively, compared to the reference beam. Furthermore, the failure mode changed from brittle to ductile failure. Also, one of the main advantages of this technique is allows to increase of (ρ) up to 8.55% (4.15ρb) without needing the compressive reinforcement. The results of this study indicate that the using SFRC layer in the compression zone is an appropriate and economical method to provide high flexural capacity and ductility over‐reinforced concrete beams. [ABSTRACT FROM AUTHOR]

Ultra‐high performance concrete (UHPC) prefabricated beams are competitive in accelerated bridge construction. However, their broader application has been hindered by limited large‐scale tests and inaccurate design methods. To fill this gap, the authors conducted an experimental investigation on the shear and flexural performance of UHPC pi‐beams using two full‐scale specimens. One specimen was a precast UHPC beam, while the other was a composite beam with a normal concrete slab on the UHPC beam. The primary focus was on crack propagation, ultimate capacities, and failure modes. To complement the experimental findings, the extended finite element method (XFEM) was developed as a numerical approach. Nevertheless, relying solely on XFEM to understand real structural behavior is prone to misinterpretations. Moreover, the shear and flexural capacities were evaluated using existing codes and compared with the experimental results. The comparisons revealed that the predictions of shear capacities were at least 15% lower than the experimental values, whereas the flexural capacities showed acceptable agreement. To address this, the authors introduced the limit equilibrium method, leading to a more accurate prediction of shear capacity for UHPC beams with a deviation of <2%. [ABSTRACT FROM AUTHOR]

To study the influence of the defects on the flexural behavior of laminated T‐beams, full‐scale beam tests of three reinforced concrete laminated T‐beams with incomplete bonding and one non‐defective reinforced concrete laminated T‐beam were conducted under monotonic loading. The results showed that the failure modes and crack patterns of the defective beams were similar to those of beams without defects. However, horizontal cracks appeared in these defects. Although the peak loads of the four specimens were relatively close, the difference in the maximum deflection was distinct. The deflection span ratio of each specimen exceeded 1/17, and the displacement ductility ratio exceeded 15. The results indicate that internal defects have only a slight influence on the flexural capacity of laminated beams but significantly influence their ductility. [ABSTRACT FROM AUTHOR]

Whether the performance of carbon fiber‐reinforced polymer (CFRP)‐strengthened concrete structure is affected by chloride penetration is the key to the application under chloride environments. In this paper, the effect of chloride penetration on tensile properties of CFRP sheet, bond behavior of CFRP‐concrete, and flexural performance of CFRP‐strengthened concrete beams were studied. Results show that chloride penetration has no effect on the elastic modulus of the CFRP sheet. The tensile strength and elongation of the CFRP sheet decrease with the exposure time increase, reducing by 10% and 12.7% after 240 days. The interface failure of CFRP‐concrete is likely to occur on the concrete surface. As the exposure time increases, the interface failure develops toward the epoxy resin layer; the sliding stiffness and end slip of the interface decrease. However, the ultimate bearing capacity of the interface first increases and then decreases. As the exposure time increase, the effective bonding length gradually increases, and the failure mode of CFRP‐strengthened beams changes from bending failure to shear failure. After 120 days, the ultimate bearing capacity of the beams is significantly reduced. From three parts of materials, interfaces, and components to provide an evaluation basis for the use, regular detection, and life prediction of CFRP‐strengthened reinforced concrete beams under chloride environments. [ABSTRACT FROM AUTHOR]

Polyvinyl alcohol‐engineered cementitious composite (PVA‐ECC) exhibits strain hardening and multiple cracking characteristics under tension. Its superior tensile behavior may also influence the flexural behavior of reinforced PVA‐ECC beams. This paper investigates the load capacity and failure mode of reinforced PVA‐ECC beams in bending. Seven beams with different tensile reinforcement ratios, including six PVA‐ECC beams and one conventional concrete beam, were tested in the experimental program. The influence of reinforcement ratio on load capacity and failure characteristics was discussed in detail. Test results showed that with increasing reinforcement ratio, the ultimate load of beams was increased, but the failure mode was changed from fracture of PVA‐ECC in the tension zone to crushing in the compression zone, thereby limiting the full development of beam ductility. An analytical model is proposed to calculate the load and the vertical deflection of beams. In the model, the tension‐stiffening effect of reinforcement after cracking of PVA‐ECC is considered by defining the bond–slip relationship of reinforcement embedded in PVA‐ECC. Comparisons are made between experimental results in the literature and those calculated by using the analytical model to show the accuracy of the model in predicting the load–deflection relationship, the moment–rotation relationship, and the moment–curvature relationship. [ABSTRACT FROM AUTHOR]

The study aims to identify flexural behavior of RC beams strengthened using three different fiber‐reinforced polymers (FRPs) with differential cross‐sections configuration (i.e., middle and support sections). The experimental and calculations results of strengthening methods for RC beams were investigated utilizing FRPs under flexural loading. The strengthening FRP materials (CFRP, AFRP, and GFRP) were externally attached to the surface of the samples with U‐wrapped shape at the three different regions of the beams. The experimental results were compared with the fiber polymer systems of the American Concrete Institute according to the ACI 440.2R‐08 standards. The results demonstrated that RC‐9 specimen reinforced using AFRP exhibited higher load capacity performance than the others. The RC beams strengthened at both middle and support area exhibited more ductile behavior, which depends on the failure mode. Less crack formation was seen in the RC‐10 beams reinforced with AFRP, both in the middle and in the support area, compared with reference sample. The experiment revealed that FRP U‐jackets could be a promotive alternative to improve structural performance greatly and provide reliable and suitable solutions for sustainable buildings. [ABSTRACT FROM AUTHOR]

This paper investigates the shear performance of corroded reinforced concrete (RC) beams with different stirrup corrosion rates and strengthening interventions. In this work, eight corroded beams strengthened with various interventions, including U‐shaped stirrup, bonded steel plate, and anchored steel plate strengthening techniques, were tested under static loading. The experimental shear capacity, load–deflection response, and failure modes of the unstrengthened and strengthened specimens were carefully studied. Three shear capacity models based on GB50010‐2010, ACI 318‐08, and Eurocode 2 codes were proposed and discussed. The results showed that all specimens have the same failure mode, that is, the shear–compression failure. The shear capacities are improved by 17.36%–23.61% and 23.76%–38.46% by these interventions for the specimens with 10% and 20% stirrup corrosion rates, respectively. The anchored steel plate technique provides the maximum improvement in the shear capacity. Additionally, the increased stiffness of corroded specimens with strengthening interventions is apparent when the corrosion rate is 10% but not obvious when the corrosion rate is 20%. The models based on GB50010‐2010 and ACI 318‐08 codes were proved to have higher accuracy but may overestimate the shear capacity. In contrast, the Eurocode 2‐based model comes with relatively low prediction accuracy but conservative results, and it is recommended for engineering design. [ABSTRACT FROM AUTHOR]

In this work, the theoretical model for predicting the flexural behavior of steel‐reinforced basalt fiber‐reinforced concrete (RBFRC) beams was developed and the results were experimentally validated. The experimental results presented two failure modes of the RBFRC beams including flexural failure and flexural‐shear failure. The load‐carrying capacity, deformation ability, and crack resistance of RBFRC beams failing in flexure can be significantly enhanced with the addition of chopped basalt fiber. To verify the theoretical model, the predicted results were compared with the experimental results of RBFRC beams, and the relative error between the two methods is very small. Based on the theoretical method, a parametric study was conducted to identify the influence of several crucial materials and structural parameters on the flexural behavior of RBFRC beams. [ABSTRACT FROM AUTHOR]

The present investigation deals with the flexural behavior of a new type of Hybrid steel, polypropylene Engineered Cementitious Composite (Hf‐ECC) ‐ Lightweight Aggregate Concrete (LWAC) encased Hybrid Steel Truss Composite (HSTC) beams and detailed parametric study of HSTC beams using Abaqus. Eight simply supported beams fabricated with identical hybrid steel truss, but with varying depths and layer arrangement of Hf‐ECC and LWAC were experimentally tested to investigate the effects of Hf‐ECC depth of HSTC beam on the ultimate load‐carrying capacities and failure modes. Test results show that cracking, yield, ultimate moments, and the ductility of HSTC beams are improved by increasing the depth of Hf‐ECC due to the excellent tensile properties of Hf‐ECC. In addition to the above enhancement, it is also found that the combined use of Hf‐ ECC and LWAC could improve the beams' general ductility and considerable energy dissipation capacity due to Hf‐ECC's excellent deformation ability besides reducing beams' weight. In addition to experimental work, a finite element model is used to predict the load‐deflection behavior of Hf‐ECC and LWAC‐encased HSTC beams. [ABSTRACT FROM AUTHOR]

Nineteen 2D nonlinear finite element analysis (NLFEA) solution strategies were benchmarked against a wide variety of 101 experiments on reinforced concrete beams failing in bending, flexural shear, or shear compression. The relatively high number of solution strategies was motivated by the conviction that choices for the constitutive models, the finite element kinematics and equilibrium settings will interact, and must therefore be tested in conjunction. Modeling uncertainty distribution parameters are presented for the 19 solution strategies, using all beams, and using beams with and without stirrups separately. The resulting statistics are discussed against the correctness of the simulated failure modes and failure loads, revealing that rotating crack models perform well for the relatively ductile failures in beams with stirrups, while fixed crack models perform better for the more brittle failures in beams without stirrups. The tailored solution strategies that predict failure modes correctly, imply a log‐normal distribution of the modeling uncertainty with relatively low coefficients of variation. The outlook is that these estimates of the statistical properties of the modeling uncertainties could serve as a basis within safety formats. [ABSTRACT FROM AUTHOR]

This paper experimentally investigated the flexural and ductile behaviors of ultra‐high‐performance concrete (UHPC) beams. The failure modes, deflection, ductility, concrete strain, and reinforcement strain were tested using eight UHPC rectangular beams. The experimental parameters were the reinforcement ratio, the reinforcement diameter, and the UHPC cover thickness. The experimental results showed that all specimens exhibited flexural failure characterized by the yielding of steel rebars, multiple micro‐cracks, one localized macro‐crack, and slight crushing of UHPC. It was concluded that increasing the reinforcement ratio significantly enhanced the stiffness, flexural capacity, and ductility of the rebar‐reinforced UHPC beams, whereas showed little effect on their cracking load. Meanwhile, both the reinforcement diameter and UHPC cover thickness in the range investigated here had little influence on the flexural performance of UHPC beams in the elastic stage and crack development stage, whereas exhibited different influences in the yield stage. Besides, increasing the reinforcement ratio was in favor of presenting the deflection‐hardening behavior, while the reinforcement diameter and UHPC cover thickness had little influence on the deflection‐hardening behavior. The analytical models were established to predict the yielding load, peak load, and ultimate load of rebar‐reinforced UHPC beams, and the predictions showed good agreement with the experimental results in this study. Also, the steel reinforcement could show a dominant role in the bearing capacity by increasing the reinforcement ratio. A post‐yielding capacity factor λ was proposed, which could reasonably evaluate the deflection‐hardening and deflection‐softening behavior of UHPC flexural members in the present study. Based on other experimental results collected in literature, three different ranges for the post‐yielding capacity factor, namely, λ ≤ 0.7, 0.7 < λ < 0.9, and λ ≥ 0.9, were identified, corresponding to the deflection‐softening behavior, transition stage, and deflection‐hardening behavior, respectively. [ABSTRACT FROM AUTHOR]

Application of fiber‐reinforced polymer (FRP) reinforcement in concrete beams may cause large deflection and crack width, as well as low shear capacity and ductility due to relatively small stiffness of FRP materials. To avoid these unfavorable factors and evaluate the shear behavior of FRP‐reinforced structural members, a high‐performance strain‐hardening cementitious composite (SHCC) is introduced to substitute conventional concrete in reinforced beams, and four‐point bending test is conducted in this study. Six FRP‐reinforced SHCC beams with different transverse reinforcement ratios and shear spans, as well as one concrete reference beam, were tested. According to the test results, the FRP‐reinforced SHCC beam showed enhanced shear carrying capacity and superior ductility compared with the concrete beams. The shear span to effective depth ratio as well as the stirrup ratio has a great influence on the shear behavior of FRP‐reinforced SHCC beams, including the failure mode, load‐carrying capacity, crack propagation, and ductility. Finally, a simplified truss‐strut model for predicting shear carrying capacity of steel or FRP‐reinforced SHCC beams is proposed, and a good agreement is achieved with the experimental results. [ABSTRACT FROM AUTHOR]

Torsional tests for four concrete beams reinforced with glass fiber reinforced polymer (GFRP) bars as torsional longitudinal reinforcements and glass textile grids as torsional transverse reinforcements are conducted to study the possibility in using noncorrosive and cold‐bendable glass textile grids as minimum torsional transverse reinforcements. These beams are compared with three control beams reinforced with GFRP torsional transverse reinforcements. Two investigated variables in this experimental study are the number of layers of textile grids and the orientation of torsional transverse reinforcements. Grade 40 fine‐grained concrete is used for all tested beams. A standard pure torsional test is used to study the torsional behaviors of these beams. The experimental behaviors of the tested beams are compared in terms of recorded torque‐twist curves; strain gauge readings in transverse, longitudinal reinforcements, and concrete at critical positions; observed cracking patterns and failure modes. The experimental results are compared with the recommendations for minimum torsional transverse reinforcements in the existing design codes and guidelines such as the ACI 318‐19, EC2, ACI 440.1R‐15, and CSA S806. The comparison indicates that the existing guidelines are unsafe in estimating the minimum transverse torsional reinforcements for glass textile‐reinforced concrete beams. [ABSTRACT FROM AUTHOR]

In this study, constant‐amplitude fatigue tests were first performed on two types of reinforced concrete beams containing corroded reinforcements and carbonized concrete (involving corroded reinforcements). Then, the stiffness degradation behavior and the failure modes of these beams were analyzed. The results show that the stiffness of a beam first rapidly decreased and then slowly decreased under constant‐amplitude fatigue loading. In addition, the corrosion ratio of the reinforcement could affect the failure mode, and fatigue failure occurred in the compression zone of the concrete. Subsequently, a degradation equation of the bending stiffness for a damaged beam and a deflection equation that considers fatigue loads and accumulated damage were proposed. Furthermore, a staged linear curve for predicting the fatigue life of a reinforced concrete beam within certain corrosion ratio ranges was developed. [ABSTRACT FROM AUTHOR]

This article presents the details of a fire test on eight prestressed reactive powder concrete (RPC) beams cured with 150°C hot air. The test specimens varied in load ratio, cover thickness of tendons, bonded and unbonded tendons, and partial prestressing ratio. The thermal fields, deflection behavior, effective prestress, fire endurance, failure modes, and crack patterns of the beams were observed and recorded, revealing that no obvious fire‐induced spalling occurred on the prestressed RPC beams. The fire test results indicate that the failure of prestressed RPC beams was driven by direct fire exposure and fracture of tendons and longitudinal rebars after generation of wide cracks in the beams. In extreme fire, prestressed RPC beams that were under‐reinforced at ambient temperature may fail as low‐reinforced beams. Fire resistance of the prestressed RPC beams dramatically improved with a decrease of load ratio and increase of cover thickness of tendons. Bonded prestressed RPC beams showed superior performance over equivalent unbonded prestressed RPC beams in fire. The whole‐scale transferring effect of prestress loss in unbonded beams should be considered for fire resistance performance design based on structural systems. [ABSTRACT FROM AUTHOR]

In the present investigation, the structural behavior of reinforced geopolymer concrete (RGPC) beams containing steel fiber has been studied. Four‐point flexural loading condition was applied in this experimental study; for testing the RGPC beams. The deflections of the RGPC were gauged at the mid‐span of the specimens. The crack patterns and failure mode of RGPC beam specimens were measured during the testing process. From these measurements, it has been observed that the steel fibers control cracking due to plastic and drying shrinkages. The length and width of cracks generally improved with the increment of steel fiber content. The findings also indicate that the flexural strength and elastic modulus of RGPC are remarkably enhanced due to the incorporation of steel fibers. Furthermore, the failure mode of RGPC is almost similar to the failure mode of conventional concrete. However, the RGPC performed better than the conventional concrete in terms of flexural strength and other mechanical properties. It has also been noticed that the increase of a/d ratio results in shifting the flexural failure mode in the mid‐span regions towards the support points. The experimental results have been compared with the relevant published literature as well as with the different standard codes. [ABSTRACT FROM AUTHOR]

The focus of the research is to evaluate the flexural behavior and performance of glass fiber reinforced polymer (GFRP) repaired reinforced concrete (RC) beams corroded to different levels using acoustic emission (AE) techniques. A significant improvement in the flexural characteristics of the GFRP repaired corroded beams is observed with a change in failure mode from brittle to ductile. The benefits of GFRP repair in corroded RC beams are further clearly demonstrated by AE monitoring parameters of cumulative AE hits and their amplitudes. A significant improvement in the number of AE hits and the reappearance of AE cracking phases after repair of corroded beams indicate the efficiency of AE technique to monitor repaired structures also. A pictorial representation of the development of microcracks beneath the surface of concrete and GFRP to the formation of macrocracks is well demonstrated in an AE event plot. The assessment of local damage in RC beams using AE techniques subjected to simultaneous loading and corrosion and their further repair would facilitate in‐situ nondestructive evaluation of actual RC structures in future for detecting damage beneath the surface even after FRP repair. [ABSTRACT FROM AUTHOR]

The residual resistance of corroded reinforced concrete members depends on steel and concrete cross section loss and deterioration of material properties for steel, concrete, and bond. The paper considers these phenomena in models for resistance calculations, starting from the cross section and stress field models in Model Code 2010. The aim of this study is to develop models proposed by Coronelli et al., using a recently proposed approach by Blomfors et al. to model bond of corroded reinforcement based on the Model Code 2010 bond stress–slip relation. Flexure, shear, and anchorage resistance of corroded reinforced concrete beams are studied. The verification is carried out by comparison with tests on corroded beams with different shear span‐to‐depth ratios. The bond deterioration leads to changes in the inclination of the stress fields in B regions and anchorage failures. The reduced resistance and the changes of the failure modes caused by the deterioration phenomena are captured by the modeling approach. [ABSTRACT FROM AUTHOR]

In this paper, seven specimens were designed to study the influence of the height (h), width (b), and reinforcement ratio (ρ) of ring beam on the failure mode, bearing capacity, deformation, and equivalent stress–strain relation of joint core reinforced with ring beam for connection of polyvinyl chloride fiber‐reinforced polymer confined concrete column and reinforced concrete beam. The experimental results indicated that the crushing of concrete in the joint core dominated the failure of specimens. The ultimate, yield bearing capacity and axial strain decreased with the increase of height, while raised with the improvement of width or reinforcement ratio. The growth of the strains of reinforcement and concrete accelerated with the increment of height, while decelerated with the rise of width or reinforcement ratio. Subsequently, based on the local compression theory, confined concrete theory, and the principle of superposition of multiple confinement, considering the influence coefficient of joint height βh and the enhancement coefficient of stirrups αs, a new formula was proposed to estimate the ultimate bearing capacity of specimens under axial local compression. Then, on the basis of Mander's model, taking the correction parameter η into consideration, a new model of equivalent stress–strain relationship was established. Verification results showed that the models proposed in this research agreed well with the experimental results. [ABSTRACT FROM AUTHOR]

This paper investigates the influence of cyclic preloading on the fatigue behavior of reinforced concrete (RC) beams rehabilitated with near surface mounted (NSM) carbon fiber reinforced polymer (CFRP) reinforcement. The study includes eight RC beams with dimensions of 152.4 × 152.4 × 1,521 mm. Strengthened and nonstrengthened specimens were tested under monotonic loading to obtain the flexural static capacity. Two strengthened specimens were tested as a reference under constant amplitude cyclic stress without prefatiguing. Four nonrehabilitated RC beams were prefatigued to simulate service loading conditions. Later, these RC beams were rehabilitated with NSM CFRP reinforcement and tested under the same cyclic stress range of the reference specimens. Mid‐span deflection, strain of tension steel rebars and CFRP rods, stiffness degradation, and energy dissipation were analyzed and evaluated. Experimental results show that the rehabilitated prefatigued RC beams had similar stiffness degradation and failure modes to the reference strengthened RC beams. The rehabilitated RC beams had an improvement in the fatigue responses when compared to the reference strengthened RC beams. Moreover, the postfatigue monotonic behavior of the rehabilitated RC beams showed an increase in the elastic modulus and a decrease in ductility. [ABSTRACT FROM AUTHOR]

Test setups and loading histories aim to replicate the real conditions of the building structures. However, most of the tests on beams found in literature do not include gravity loads in the cyclic loading history. An experimental campaign was carried out. Two beam specimens, named CB0 and CB1, designed to exhibit different failure modes were subjected to a loading protocol that involved the imposition of reversed cyclic loading and simultaneous gravity load. The aim was to validate the test procedure for different beam failure modes. Consequently, specimen CB1 failed by rupture of the tensile reinforcing bars while specimen CB0 failed due to concrete crushing and buckling of the compressed reinforcing bars. Results show that the presented loading protocol does not control the failure mode of the specimens. The specimens were also simulated numerically, and the results were comparable with the experimental observations in terms of load capacities, crack patterns, and failure modes. [ABSTRACT FROM AUTHOR]

This paper presents the efficiency of using prefabricated ultra‐high performance fiber reinforced concrete (UHPFRC) plates in shear strengthening of reinforced concrete (RC) beams experimentally and numerically using finite element method. In order to ensure high quality and facilitate the strengthening process on site applications, it has been considered to apply UHPFRC as a plate pasted on concrete surface using epoxy. Tested specimens included four strengthened beams besides three control beams. Strengthening the RC beams was based on the use of two different techniques; (a) one longitudinal side strengthening (b) two longitudinal sides strengthening. Moreover, strengthening RC beams with reinforced or non‐reinforced prefabricated UHPFRC plates was also investigated. Results show that UHPFRC plates significantly increased the maximum load capacity, ductility and mid span reinforcement strain of the strengthened RC beams comparing with reference beam failed in shear. Also, steel connectors used in reinforcement of UHPFRC plates prevented debonding failure mode. A three‐dimensional (3D) finite element model (FEM) of the tested beams was also developed to predict the behavior of these specimens strengthened in shear. The adhesive layer was simulated using cohesive surface model to consider the slippage between concrete surface and UHPFRC plates. Results of the FEM showed good agreement with experimental results, as they were able to predict the behavior of the beams with high accuracy. [ABSTRACT FROM AUTHOR]