Search

The present paper aimed to experimentally investigate the effect of micro steel fibers (MSF) on the structural shear behaviour of SCC deep beams made of 100% RA. Flexural test were performed on six simply supported deep beams under a single-point loading scheme at shear span to effective depth ratio (a/d) of 1.2 and 1.5. Two SCC beams were made of natural aggregates (NA) without MSF, two beams were made of a 100% RA without MSF, and the last two beams were made of RA with MSF at a volume fraction (vf) of 1%. The parameters considered in this research included load deflection response, ultimate shear failure load, and cracking pattern. The obtained results indicated that using RA considerably reduced the shear capacity of reinforced SCC deep beams in comparison with control mix, and that reduction was more pronounced when a/d ratio was decreased. At a given shear load value, the deflection of RA-based beams was higher than that of NA-based beam, regardless of a/d ratio. This clearly reflected the inferiority of RA particles. However, a comparable or even superior shear strength can be reached when up to 1% MSF was added. Based on this experimental investigation, it was demonstrated that the crack patterns of SCC deep beams prepared with NA, RA, and even MSF, were generally identical. Nevertheless, the crack width for beams with a/d of 1.5 seemed to be more visible than that of a/d of 1.2. [ABSTRACT FROM AUTHOR]

The NSM technique has been used as a contemporary method to fix flaws in structural parts and improve their flexural and shear strength. For this method to work, a number of practical experiments were carried out to understand the behavior of the component that was fortified using the NSM technique for flexure and shear. This research presents an experimental study on the shear behavior of lightweight reinforced concrete (LWRC) beams strengthened in shear by NSM glass fiber reinforced polymer (GFRP) bars. Six LWRC beam specimens with a cross section dimension of 160 mm x 250 mm and a total length of 1700 mm were used in the experimental testing. The control specimen was an un-strengthened LWRC beam, whereas the other five beams were shear-strengthened using various numbers and configurations of NSM GFRP. The spacing, inclination angle, and diameter of the NSM bars used in the strengthening of the LWRC beams are the primary characteristics evaluated in the experiment. All LWRC beams are subject to two point loads until failure. The load-displacement curves, crack patterns, and failure modes of all RC beam specimens were monitored, recorded, and evaluated in this study. Results have shown The sample SG6 (150mm) 45° showed the highest increase in the ultimate load of the strengthened beams, reaching 149% compared with the control beam, while the sample SG6 (300mm) 90° showed the lower increase in the ultimate load of the strengthened beams reaching 38.5% compared with the control beam. The results also showed that GFRP bars work to improve the shear strength of test samples that were strengthened using the traditional NSM method. [ABSTRACT FROM AUTHOR]

The purpose of this research is to conduct an experimental examination of the behavior and failure of deep reinforced concrete (RC) beams reinforced with near surface mounted (NSM) glass fiber reinforced polymer (GFRP) bars. In the experimental testing, ten RC deep beams with cross-sectional measurements of (400160) mm and a total length of (1500) mm were used. The beams were strengthened with NSM GFRP bars in a variety of strengthening configurations, with one beam specimen left unstrengthened as a control. Two loading points were applied to all RC deep beams until failure at various shear spans and effective depth ratios (a/d). The effects of GFRP bar diameters, spacing, and inclinations on the performance of reinforced deep beams were investigated and addressed. The test results revealed that the ultimate strength of strengthened beams increased significantly. Furthermore, more specialized strengthening techniques increased ductility while decreasing diagonal crack width. [ABSTRACT FROM AUTHOR]

Reinforced concrete deep beams are commonly used in high-rise buildings to support heavy loads. Openings are typically given in deep beam construction for accessibility and to permit essential services such as power, ventilation, and network system access. However, deep beams' openings can generate various beam behaviour problems, including reduced beam strength, excessive cracking, and deflection. This investigation conducted the behaviour of longitudinal circular opening-reinforced self-compacting concrete deep beams. The behaviour of six specimens have been studied in this research; different longitudinal circular sizes openings (circular opening in the tension zone with a diameter of (4in, 3in, 2in, in addition to the ratio of the void) were utilized in this study, all specimen have the same dimensions ((1600)mm length, (425)mm total height, and (250mm) width), For comparison purposes, one of these specimens was cast with a solid section (without longitudinal opening). The study's primary consideration is longitudinal openings, size of openings, voiding ratio and openings reinforcement. The crack pattern, deflection, and load capacity were measured and discussed. The experimental program reveals that longitudinal openings reduce the loading capacity of SCC reinforced concrete deep beams; increasing the opening size also lowers the capacity load. The small circular opening's structural behaviour approximated that of the reference specimen. The use of steel pipes to strengthen the longitudinal opening was found to be a practical specimen in increasing deep beam stiffness and load carrying capacity; the ultimate load was enhanced by (12.33) per cent over an unreinforced opening beam. [ABSTRACT FROM AUTHOR]

The features of the assessment of the bearing elements technical condition are considered. The necessity of examining ceilings and beams in an unfinished building, which has a long-forced break in construction, is substantiated. In practice, it became necessary to determine the suitability of a building for normal use after damage resulting from downtime. For this purpose, monitoring of the technical condition of the ceilings and beams of the building was carried out using methodological and instrumental equipment for the inspection of building structures. The results of inspection of structures and reinforcement of ceilings and beams are considered. In accordance with the current regulatory documents, the reinforcement system was checked, and the strength of the concrete ceilings and beams was calculated. The list of defects and damages is taken into account when carrying out verification calculations of reinforced concrete ceilings and beams. Measures and recommendations for the repair of reinforced concrete ceilings and beams are proposed, conclusions about the bearing capacity of structural elements are drawn. [ABSTRACT FROM AUTHOR]

Concrete is the largest contributor to carbon emissions in the construction sector. However, recently there have been no studies analyzing embodied carbon in normal concrete with specific reviews on one structural element and reinforced concrete buildings with variations in structural configuration. The purpose of this study is to determine the influence of material variables and designs of reinforced concrete beam and reinforced concrete buildings on the value of embodied carbon which can then be used as a consideration of low-emission building design. This research was conducted using parametric analysis methods using Building Information Modeling-based applications and ICE Cement, Mortar, and Concrete Model – V1.1 Beta. Reinforced concrete beam were designed with single reinforcement with minimum and maximum reinforcement ratio and in cross-sectional dimension ratios, namely 1:3, 1:2, and 2:3. Reinforced concrete buildings were designed with 3 variations of column elevation, namely 3000 mm, 3500 mm, 4000 mm, and 3 variations in beam span, namely 3000 mm, 4000 mm, 6000 mm. The results of this study show that the greater the ratio of width to height of the beam (b/h) and the reinforcement ratio, the higher the embodied carbon produced. The denser and higher the elevation of the column used, the greater the embodied carbon produced. In reinforced concrete buildings, the cradle-to-gate stage produces embodied carbon by 49.69%, the construction stage by 2.93% and End of Life by 4.39%. [ABSTRACT FROM AUTHOR]

High-Strength Self-Compacting Concrete (HSSCC) is a type of concrete with superior mechanical material properties and the capacity to self-compact without using a vibrator. Many innovations have been performed to improve the characteristics of HSSCC. In the previous experimental work, the authors examined the mechanical properties of HSCC with 12.5% metakaolin and 0-15% silica fume as a partial substitute for cement. Since metakaolin and silica fume have smaller particle sizes than cement, they can fill voids between aggregate and increase the concrete density. Further research at the structural level is required to obtain a more comprehensive understanding of the effect of partially replacing cement with metakaolin and silica fume. The present study analytically investigates the flexural behaviour of reinforced HSSCC beams using the Response 2000 program. As simulation input data, laboratory-determined mechanical properties of the material were utilized. In this study, five beam models constructed with different material mechanical properties were evaluated and compared to each other in terms of flexural cracking strength, ultimate strength, deflection, and crack patterns. [ABSTRACT FROM AUTHOR]

The use of fly ash as a partial replacement for cement in concrete production is one solution to reduce the effects of global warming. In this context, HVFA-SCC concrete is a type of environmentally friendly concrete with advanced technology. However, the use of SCC concrete still faces challenges, such as the lack of aggregate interlock effect that can reduce the shear strength of concrete beams. Therefore, this paper examines the behavior of 100x185x1300 mm HVFA-SCC concrete beams with the use of fly ash as a substitute for cement at 50% of the total binder weight. Beam testing was conducted using a four-point loading system on three test beams. The results of the beam tests showed the formation of initial diagonal tension cracks and primary diagonal cracks at loading of around 30% and 95% of the ultimate shear load, respectively. After the primary diagonal cracks formed, crack propagation rapidly occurred and triggered the failure of the concrete beam shear. [ABSTRACT FROM AUTHOR]

Long-term deflection is the deflection occurred as a function of time and is influenced by several factors such as humidity, temperature, treatment conditions, stress-strength ratio, age of concrete, and so on. This study aimed to analyze the long-term deflection of reinforced concrete beams with onyx waste aggregates and normal aggregates using Gibson R.E & Lo.KY rheological model analysis. The test used reinforced concrete beams with dimensions of 15 x 25 x 200 cm, with a loading duration of two weeks. Based on the results of the experimental tests and the analysis of rheological models, it was found that the deflection value of reinforced concrete beams with onyx stone waste aggregate was greater than that of reinforced concrete beams with normal aggregates. It was indicated by the deflection value obtained from the experimental test for two weeks of loading on the onyx beam of 0.315 cm, and the value of the rheological model prediction was 0.315 cm. The deflection value obtained from the experimental test for two weeks of loading on a normal beam was 0.220 cm, and the value of the rheological model prediction was 0.220 cm. This showed that the results of the rheological model analysis can be used to predict the long-term deflection of reinforced concrete beams. [ABSTRACT FROM AUTHOR]

The main causes of structural failure have been steel reinforcement corrosion of reinforced concrete (RC) structures. Early steel corrosion detection could restrict the cost of the rehabilitation work and minimize the extent and location of required repair or replacement. Of the test of deteriorated concrete beams due to steel corrosion being tested under loading using the non-destructive testing (NDT), i.e., acoustic emission method (AE) is the more efficient method of RC structure evaluation and early corrosion detection. The tests were conducted on corroded beam specimens subjected to cyclic stress before the onset of the initial cracks for a secondary source of AE at the highest load level (i.e., 4 kN). Ib-value and cumulative signal strength (CSS) of AE are recommended to analyze the effects of severe corrosion damage before the initial cracking becomes apparent; as corrosion levels increase, the CSS ratio also increases. It shows that damage caused by a loss in the cross-section of the beams has occurred. [ABSTRACT FROM AUTHOR]

In the practice of designing reinforced concrete structures is more widely used the beam model, so it showed to good advantage for assessing the bearing capacity of the structures. However, in some cases when a more detailed picture of the behavior of the structure is needed the beam model is not suitable by its mathematical nature, which is extremely one-dimensional. The paper deals with numerical approach in developing modern method for calculating of reinforced concrete structures taking into account the elastoplastic characteristics of the material. For more accurate description of behavior under loads it is used the relations for the increment of stresses with the corresponding deformations through the matrix of limiting state, obtained on the basis of the transformation of the certain yield function of the material. The new approach for structure analysis and corresponding algorithms of numerical calculation are developed. It is given an example of determining bearing capacity of reinforced concrete beam, where the results of the solution are compared with the known solutions of structural and solid mechanics. [ABSTRACT FROM AUTHOR]

Beams of reinforced concrete with flanges have been utilized extensively in a lot of applications in structural engineering. The total behavior of this type of member has been studied experimentally and analytically. In this paper, a finite element method-based numerical analysis was used to presented the reinforced concrete's behavior with flanges during the pre-and post-cracking level of loading up to their ultimate stress. Different types of flanged reinforced concrete beams were analyzed, and the results from finite element (F.E.M) were compared with experimental and analytical data. The impact of concrete's compressive strength has been examined. In general, excellent agreement has been obtained between the results of finite element and experimental tests. Also studied numerically is the distribution of concrete longitudinal compressive stresses and tensile stresses along the steel reinforcement. It is found that for high-strength concrete, the ACI Code 318M-14 underestimates the collapse moment of flanged reinforced concrete beams. [ABSTRACT FROM AUTHOR]

The materials which are widely used for construction of the building industry are concrete. But the production of cement releases numerous amounts of greenhouse gases (CO2) that leads to increase in global warming. So, an alternative to cement has to be identified. The current research focuses on the use of mineral admixtures such as fly ash, rice husk ash, and silica fume in place of cement in concrete with the addition of coir fibre. The mechanical properties of the specimens were studied with percentage replacement of cement with various mineral admixtures. With the optimum results flexural behaviour of reinforced concrete were studied. Reinforced concrete beams with percentage replacement of silica fume offered better load carrying capacity. [ABSTRACT FROM AUTHOR]

Composites made of fiber-reinforced polymer TCP) are widely utilized in modem concrete technology since their supremacy over conventional steel reinforcement. These stuffs have a high strength potential, opposition to corrosion, they are used as main reinforcements in reinforced concrete (RC) beam members when combined with adhesives and anchorages. FRP strengthening methods using a mixture of fibers will increase in quality and plasticity of reinforced concrete beams. Various fiber, designs and strengthening method all affect the all-around strength of FRP composites in reinforced concrete beams. The review clear-cuts jacketing and confinement technique of reinforced concrete beam strength and using FRP. It reveals that these composites of FRP are adjusted to preserve the strength of weakened and corrosive beams while alert offering excellent durable and insulation. It also offers a clear description of FRP composites-RC beams subjected to strengthening and retrofitting methods. [ABSTRACT FROM AUTHOR]

Near-surface mounted (NSM) fiber-reinforced polymer (FRP) reinforcement is an innovative, serviceable, and beneficial technique for RC (reinforced concrete) structure enhancement. Previous studies have proven that the epoxy-resin bonded NSM FRP method effectively achieved shear and flexural strengthening. However, for torsion strengthening, only a few researchers have utilized the NSM approach, and no research has focused on using GFRP. bars and epoxy adhesives. In this study, the behavior of RC beams under combined torsion is investigated. when they have been enhanced with NSM GFRP and steel bars. Three RC beams with dimensions of (150×250×2000) mm (width x depth x length) were considered in the experimental tests. One RC beam is not strengthened and used as a control beam C.B., while the other two beams are strengthened with NSM GFRP bars and NSM steel bars. Test results in terms of twist angle-applied torque curves, the torque of initial cracks, ultimate torque capacity, and ultimate angle of twist were measured and analyzed. It has also been shown that the RC beam' torsional performance can be substantially improved by using NSM GFRP stirrups by about 73% higher than NSM steel stirrups. [ABSTRACT FROM AUTHOR]

Among Non-Destructive Diagnostic Techniques (NDTs), Acoustic Emission (AE) is particularly useful to evaluate and/or monitor the material properties of structures and their degradation over time. For instance, this method permits identify early micro-fractures by depicting the release of mechanical energy of an elastic wave radially propagating through the material from the fracture zone, obtaining the possibility to localize the damage of the investigated specimen. Despite the large number of localization strategies that have been examined in the literature, there are nowadays no specific and standard guidelines. Within this framework, in this paper, the results of an AE experimental test performed on a prestressed reinforced concrete joist subjected to a four-point bending load are presented. The data collected during the test will be analysed focusing in particular on the hits cumulative curves and hits energies for each channel, showing how the overall behaviour of these parameters provides interesting insights into the specimen response. Finally the linear localization of the events produced during the test will be reported and correlated with the theoretical expectations, in terms of tensile and shear cracks. The results will confirm the expectations, reporting the main events in the central region of the specimen, that experiences the maximum constant bending momentum. All the findings of this test will show a setup for the early detection of micro-fractures in prestressed reinforced concrete elements, providing an interesting base for the extension of the technique to buildings and general structures. [ABSTRACT FROM AUTHOR]

The Acoustic Emissions (AE) technique is gaining more and more importance in the non-destructive testing research area, especially for reinforced concrete elements. The ultrasonic signals produced by damage to the concrete can be detected by proper piezoelectric sensors, both resonant or broadband, and can be further processed with dedicated software, to calculate single event parameters, as well as collective variables. The online and/or offline analysis of these parameters allows for the detection of defects and to monitor of the integrity of elements without damaging the specimen, which is of great importance for structural health assessment. In this paper, the authors present a four-point bending test on a Reinforced Concrete Beam, performed at the STRENGTH Laboratory of the Department of Civil Engineering at the University of Salerno, in which an AE detection and analysis system is used. The data processing will show how the AE technique is useful to localize the fractures in the specimen and highlight the area in which the final failure will occur at about 60% of the maximum load. [ABSTRACT FROM AUTHOR]

Architects try to create structures that are affordable and have adequate requirements. The ability to move the supports around, capability to adapt to changes in plan geometry are most important. In addition to these requirements intersections, bifurcations, carriageway widening, and curves with small requirements radiuses are also remarkable needs that box girder provided them, besides, erection speed and aesthetic acceptance, construction's shallow depth, in particular at multilevel interchanges. Other significant qualities include its economy, ease of maintenance, and flexibility to respond to variations in traffic density. Due to its high torsional stiffness in the closed section, the box girder is the structural type that is best suited to satisfy these criteria. This guarantees that eccentric forces are distributed transversely well, from irregularly positioned support reactions and superimposed loading, allowing for efficient use of the entire cross section, consequent material savings and reduced construction depth. Several previous studies on reinforced concrete (RC) box girders are reviewed in this paper. The terms single-cell, multiple-spine, and multicell cross sections are used to characterize the key features of references pertinent to straight and curved box girder bridges. [ABSTRACT FROM AUTHOR]

The present study evaluates the flexural behavior of reinforced LWSCC (with and without) steel fiber beams. This work assesses the impact of three replacement percentages by LECA (40%, 80%, and 100%) for coarse aggregate on flexural behavior. Each of the beams under test has a whole length of (2000mm), and a net distance between supports equal to (1800mm), the beam width of (150mm). In light of the experimental outcomes, it determined that the ultimate load decreased by (12.5%, 16.7%, and 16.7%) and the inclusion of steel fiber to beams with LECA led to an increase in ultimate load with (28.6%, 30%, and 25%). The (P exp)/P theo) the ratio ranged from 1.26 to 1.4 for replacement ratios related to the LWSCC beams and varied from 1.59 to 1.75 for LWSCC beams with steel fiber. The failure mode of all concrete beams is generally perceived as a flexure-shear failure with crushing in a compression zone. ABAQUS 2021 was used to simulate a numerical analysis of experimentally tested specimens. The numerical results revealed a good correlation with experimental results, pointing toward relatively stiff numerical solutions compared with the experimental results. [ABSTRACT FROM AUTHOR]

This research is devoted to investigating shear behavior of damaged reinforced concrete deep beams repaired by CFRP. The experimental work includes testing of three reinforced concrete deep beams. One beam used as a reference specimen without damaging and repairing and the second beam (RC1) were damage at one face of beam, damaged near one support at shear region. While the last beam (RC2) was damaged at one face of beam, damaged near two supports at shear region. All Beams tested as a simply supported beam under two points loading up to failure to investigate effect of repairing material on the damaged beam. Damage length of RC beam at shear region is taken as a percentage of the effective length RC beam. The experimental variables considered in the test program includes number of damaged regions in the side face of beam with the same percentage of damaged. Deflection was recording at mid-span of the beam and first crack load was recorded. As well crack patterns were traced. From the experimental results, it was found that the ultimate load carrying capacity of repaired beams increased as compared with reference one. The increasing in ultimate load carrying capacity of RC1 and RC2 beams were (13.46%, 14.62%) respectively. [ABSTRACT FROM AUTHOR]

This paper investigates behaviour of beam that has construction joints of two concrete's age, half part considered as old concrete and the other half is a new part. Four types beams with three shapes of construction joints (45°, 60° and L shape) were used in this study. The results gave an indication that the spacemen with joint inclined 45° is the best way to consider the construction joint within the beam. [ABSTRACT FROM AUTHOR]

This study examines horizontally semicircular curved reinforced concrete beams with openings and without openings, unstrengthened and strengthened (by CFRP). One semicircular reinforced concrete beam without openings and two with four openings were tested. The test program considers beam openings and CFRP laminate confinement in opening zones. The beams were tested with two-point loads on the midspan and three supports on the ends and midspan. The CFRP laminates reinforcing the outside of semi-circular curved beams improve the ultimate load capacity and influence the post- cracking behavior and mode of failure in the presence of an opening. The twisting angle and deflection of the load midspan are shown. Compared to the control CCB, the ultimate load capacity of both specimens (CBV.O and CBV.S) reduced by approximately (21.98 and 6.9) percent. [ABSTRACT FROM AUTHOR]

This study tests steel double web sections filled with normal concrete. All beams have the same length span, cross-section (I-section), load type, and boundary conditions. The thickness and width of the flange plates on the steel beams were 120 mm and 6 mm, respectively, while the thickness of the web plates was 3 mm. All beam samples had 1200 mm between supports. One specimen without concrete was assigned as a reference beam, while the second set consisted of three double web beams filled with normal concrete. In terms of ductility, stiffness, and overall flexural capacity, the specimen filled with normal concrete outperformed the hollow steel specimen and the specimens filled with normal concrete in the middle and edge sections of the double-web steel beams, (NMF) and (NEF), respectively. [ABSTRACT FROM AUTHOR]

Reinforced concrete deep beams are commonly used in high-rise structures to withstand heavy loads. In the construction of deep beams, openings are often enclosed for accessibility and to allow access to necessary services like power, ventilation, and network systems. However, Deep beam openings can cause several problems with performance, such as decreased beam strength, significant cracking, and deflection. As a result, this study was carried out to investigate the performance of self-compacting concrete deep beams with longitudinal openings reinforced by steel tubes. The behavior of five specimens have been studied in this research; different longitudinal square and rectangular openings (square openings in a tension zone with dimensions (4in, 3in) and rectangular openings with sizes (3 in*1.5in) were used in this study. All specimens have the same dimensions (1600mm length, 425mm total height, and (250mm) width, for comparison purposes, one of these specimens was cast with a solid section (without longitudinal opening). The main problems included in this research are the presence of longitudinal openings, size of openings, voiding ratio, and opening reinforcement. The cracks pattern, deflection, and load capacity were all measured and discussed. The experimental study reveals that longitudinal openings reduce the loading capacity of self-compacting (SCC) reinforced deep concrete beams; moreover, Increasing the opening size also lowers the load capacity. The structural performance of small openings was similar to that of the reference specimen. The results showed that the reduction in ultimate and cracking load of beams with square openings was (21.57 to 24.31) percent and (17.65 to 26.47) percent, while the reduction in ultimate load and cracking load in beams rectangular openings was(20.59 to 31.37) percent and (11.18 to 34.71)percent compared with the reference specimen, due to the sharp edges in rectangular, which led to stresses concentration in the corners and large failure in the specimens. Using steel pipes to strengthen the longitudinal opening effectively increased stiffness and load carrying capacity of deep beams. [ABSTRACT FROM AUTHOR]

Experimentation regarding the study of the properties of reinforced concrete, including its behavior and its strength (RC) In this study, we illustrate how deep beams may be strengthened using near surface mounted (NSM) glass fiber reinforced plastic (GFRP) bars. In the experiment, five RC deep beams were used, each with a cross-sectional size of (400×160) mm and a total length of (1500) mm. These beams were then reinforced with NSM GFRP bars, using various strengthening configurations. One of the beam specimens was left unreinforced and serves as a control beam; the other beam specimens were reinforced using various NSM GFRP bar techniques. Each RC deep beam was put through four stress points up to failure, with varying shear spans to effective depth ratios. This research investigates and discusses the effects of GFRP bar spacing and GFRP bar inclinations on the performance of reinforced deep beams. Both impacts were examined and explored. According to the findings, the ultimate load bearing capacity of the enhanced RC deep beams was increased by around (19.6–36.3) % when compared to the capacity of the beams before they were strengthened. In addition to this, the ductility and diagonal fracture width of the strengthened RC deep beams were significantly improved. [ABSTRACT FROM AUTHOR]

The problem of the accumulation of waste around the world has received a lot of attention. One of these wastes is discarded bead wires resulting from the tire manufacturing process due to damages occurring during this process. This study presents an investigation of the flexural behavior of RC layered beams (2 and 3 layers) reinforced with discarded steel fibers (DSFs) resulting from tire manufacturing. DSFs were added to concrete in three different volume fractions of 0%, 0.25 %, and 0.5 %, and having dimensions of (40mm length×0.92 mm diameter). Four RC beams were tested under four points loading until failure. The results showed that the addition of DSF led to increased first crack load, ultimate load, and ductility. [ABSTRACT FROM AUTHOR]

This review paper presents the behavior of reinforced concrete beams strengthened with Near Surface Mounted (NSM) technology bonded with epoxy resins, as well as their importance in improving the torsional performance of reinforced concrete beams under pure torsion or combined loading. After learning about the method's effectiveness in increasing the shear and flexural strength of reinforced concrete beams, the findings improved the torsional behavior of the strengthened beams to varying degrees. The torsional behavior of the beams strengthened with CFRP ropes was superior to those reinforced with CFRP laminate. In comparison to test beams reinforced with NSM steel bars, those with CFRP wrapping displayed superior augmentation in the ultimate torsional moment. presenting convincing proof that the torsional performance parameters of torsional moment bearing capacity, torsional stiffness, angle, and crack limit may be enhanced. [ABSTRACT FROM AUTHOR]

Numerous experiments have been carried out. While typical Push-out sections and beams have been created over time, this work has illustrated the evolution of composite-beam fabrication to expedite the building process and satisfy sustainable development criteria. When designing composite beam resistance and stiffness, it is essential to reveal the most critical research on the performance of fatigue behavior of the composite system. This study aims to offer a general review of the most recent studies that have been published on composite steel-concrete in three categories, (Fatigue performance of Push-out segments, Fatigue performance of normal composite construction, and Fatigue performance of composite RC beams interconnected to bottom steel plates). [ABSTRACT FROM AUTHOR]

One of the most essential and widely used materials in construction is concrete. When it is used in flexural members, it is frequently required to have very high strength and sufficient workability. Research studies from around the world are working to create concrete with high performance by incorporating different types of fibers. The previous studies showed that implementing steel fibers in concrete leads to increase toughness, flexural strength, splitting tensile, and durability. While using glass and Polypropylene fibers led to the lower enhancement of concrete's compressive strength, they enhanced toughness, significantly splitting tensile strength and flexural strength. The mechanical results of hybrid reinforced self-consolidating concrete mixes are superior to those of other mixes except the splitting tensile strength is found that be reduced in hybrid fiber-reinforced specimens compared to concrete with steel fiber. Utilizing fibers in beams showed an enhancement in the flexural performance (cracking behavior, post-cracking flexural stiffness, flexural strength, and deflection capacity) when the increase of reinforcement ratio was up to minimum reinforcement. Fibers are controlled cracks in beams. Steel fibers improve the RC beam's first crack load and toughness by 34.5% and 40.5%, respectively. The response to applied load for hybrid fiber flexural members is found to be analogous to steel fiber members. [ABSTRACT FROM AUTHOR]

The use of ultra-high performance concrete (UHPC) to strengthen existing reinforced concrete structures has been the focus of many studies over the last few years. This novel strengthening approach has not yet been addressed in any code provisions. Consequently, further study is required to determine if UHPC can effectively strengthen structural reinforced concrete members. Due to the reality of the working environment, a joint in the strengthening overlay may be produced for various reasons, such as the end of the work time or the exhaustion of the equipped amount, among others. Additionally, there are tasks like pouring roadways in phases. This joint could make the strengthening procedure less effective. It is reasonable to redistribute the stresses across the construction joint and minimise the crack width by adding reinforcement across the joint. On the other hand, the UHPC overlay that was cast along the beam, including the supporting region, in the majority of earlier studies does not accurately reflect what would be done at the practical site. The purpose of this study is to determine how well UHPC may enhance the flexural behaviour of reinforced concrete beams. To end this, five full scale simply supported beams made of reinforced concrete were constructed. Only clear spans were cast with the UHPC layer (the distance confined between two supports). The variables included the UHPC overlay, the use of steel mesh reinforcement in the UHPC layer and the presence of construction joints in the UHPC layer. The result shows that the UHPC layer greatly increases all strengthening specimens' stiffness while delaying the onset of cracks. The ultimate load was also somewhat increased. When the UHPC overlay reinforced with steel mesh, the load bearing capacity is increased by 22.5 percent when compared to the control specimen. The UHPC layer's impact is diminished by precence the construction joint in the overlay. Additionally, a perfect bond between UHPC and normal strength concrete was observed, and there were no measurements of slips there. [ABSTRACT FROM AUTHOR]

Sometimes in the practical cases, and due to beam's complexity or/and geometry of the construction system, it is difficult to perform an external traditional strengthening technique such as externally bonded of the steel elements, composites of fiber-reinforced polymer (FRPs), bonded of section enlargement....etc. As a result, the need for the alternatives simple techniques are arise. From the structural point view, the placing (inserting) an internal structural element such as steel bracing, steel diaphragms, RC diaphragms, internal framed steel stiffening ribs inside the longitudinal hollow of the RC box beams represents the best alternative methods instead of the traditional strengthening techniques. Strengthening of reinforced normal concrete (NC) or self-consolidated concrete (SCC) box beams by RC diaphragms, steel diaphragms or bracing, and FSSRs techniques are relatively new techniques and impactful issues to be addressed and seem to be limited and not covered in earlier studies. Despite the tested beam dimensions and adopted variables, the using of internal strengthening by RC diaphragms, steel bracing, steel diaphragms and framed-steel-stiffening-ribs (FSSRs) gives a significant improvement in torsion capacity by (43-94%), (14.4-82%), (36-100%) and (45.7-122.4%), respectively. The torsion capacity enhancement is associated with increasing of both transverse torsional stiffness and toughness as well as decreasing in deformation (torque-angle of twist relation). Also, it was observed that the arrangement and numbers of used internal strengthening elements have the main effect on the amount of enhancement. [ABSTRACT FROM AUTHOR]

This paper studies the flexural experimental behavior of an asymmetric castellated composite beam with an encased steel web by RPC (reactive powder concrete) casting in a steel web beam as a composite member with and without lacing rebar under the effect of repeated loads. The cross-section is made from steel beams and concrete deck slabs. The steel beam (asymmetric section) is made from two parts of the tee section; the top part was cut from IPE 180, and the bottom was cut from IPE 200. Use RPC to strengthen the steel web with and without rebar lacing. The results show the difference in ultimate service load capacity by (+14.56) with RPC without rebar lacing and (+23.84) with RPC with rebar lacing under repeated loads. [ABSTRACT FROM AUTHOR]

The present study, clarify the effect of using CFRP anchors on the performance of CFRP that support a reinforced concrete beam. The adopted parameters were CFRP anchors layout and depth. Finite element approach was adopted via utilizing ABAQUS software for numerical analysis. Strength capacity, deflection, strains in concrete, reinforcement and CFRP, Von Mises stress, mode of failure and cracks intensity that developed in concrete were studied. Analysis results indicated that the presence of CFRP sheets and/or anchors enhances the RC beam carrying capacity and reduce the deflection and cracks propagations. [ABSTRACT FROM AUTHOR]

The global creation of discarded tires currently outnumbers its consumption in terms of recycling and reuse. As a result, vast quantities of poisonous rubber waste have accumulated, posing health and safety problems. It was suggested that waste tire rubber could be used to build the concrete structure. The impact behavior of rubberized concrete beams is investigated experimentally in this paper. This study aims to predict the maximum mid-span displacement and the maximum impact load of the rubberized concrete beams. An instrumented drop-weight testing machine was used to conduct the impact tests. In the experimental work, two main factors were studied. The first is the volumetric replacement ratio of rubber, and the second is the height of falling mass. Four reinforced concrete beams with varied rubber contents (0% 15, 25, and 35%) were tested under impact load from heights 1.5 m, 2.0 m, and 2.4 m. The results showed that the use of rubberized concrete reduces the maximum impact force by (2.93, 13.16, and 17.53%) at the rubber contents (15, 25, and 35%), respectively, at the height of 2.4m compared to the zero-rubber content. The beams with replacement ratios of 15% and 25% showed a decrease in displacement by 8.44% and 6.26%, respectively, at the mass drop height of 2.4 m, while the displacement increased by 17.26% for the beam with 35% rubber content for the same height compared to the reference beam. [ABSTRACT FROM AUTHOR]

In this study, the effect of using iron filler as a partial substitute for natural sand. Four concrete beams 150×200×1600 mm with similar steel reinforcement (one beam for each iron filing percentage) in addition to the reference concrete beam were examined. The beams were tested by ultimate load failure, final deflection, energy absorption, stiffness, ductility index, compressive stress and studying cracks, then comparing them with reference beams to evaluate the effect of iron filing on their structural behavior. The results showed that increasing the iron filing content in the concrete beams led to an increase in the final failure load, final deflection, ductility index, strain, and energy absorption were 6.7, 10.29, 11.37, 25.3, and 35% respectively, compared to the reference beam. While there was a decrease in the initial stiffness and secant stiffness of 12.6% and 3.18%, respectively, compared to the reference beam. [ABSTRACT FROM AUTHOR]

In modern buildings, the structural members may have openings for utilizing passes and the necessary efforts should be taken to keep them structurally safe. The work focused on the behavior of composite encased steel-concrete beams of longitudinal and transverse openings and investigated strengthening techniques for small and large transverse square openings. The experimental part includes poured nine (200×300×2100) mm specimens with transverse square openings in the shear span zone. Three beams attend as control beams, as well as one specimen without openings. The other two specimens had two openings located symmetrically at each shear span, At the opening zone with several methods six beams were strengthened by composite method and NSM CFRP bar. In NSM CFRP bars, Around the square openings two different configurations were installed (strengthening the specimens with a diamond strengthening scheme bar and diagonal strengthening scheme bars). Results have been discussed in terms; first cracking load, ultimate load, maximum of deflection, modes of failure, crack of patterns, toughness value, ductility index, and crack with recognizing the best strengthening proposal opening. Test results indicate that the technique of strengthening large opening with CFRP bars diagonal strengthening scheme recorded an increase in the ductility, and toughness by about 59%, and 16%; respectively compared to the control beam with a large opening. Concerning the specimens strengthened by the composite method, the load capacity is almost equal to the control beam load capacity. [ABSTRACT FROM AUTHOR]

In the present paper includes an experimental investigation to study the effect of steel fiber ratio (1 to 2%) on the flexural behavior of tubular continuous Ultra High-Performance Concrete beams and the effectiveness of longitudinal reinforcement bars on the flexural behavior of UHPC continuous beams. Therefore, eight continuous tubular beams consisting of two-span were tested under one-point loading for each span. In each group, two groups were constructed, four beams, three beams are tubular, and the fourth was solid to comparison. All beams had the matching overall length of 3000 mm, the clear span distance equal to 1400 mm for each span, the same height of 200 mm, and the same width of 150 mm. The results exhibit clear improvement in the first cracking load when increasing the steel fiber ratio from 1 to 1.5% and 2% at about 11.1 and 66.6% and increasing the ultimate load at about 5.2 and 18.4%. Then when compared MXB-5 (1.5% steel fiber) with reference solid (RE.S, 1.5% steel fiber), the increase in ultimate failure load was 20%, in addition to increasing compressive strength. The ultimate load was increased at about (2.6, 15.78, and 20.1%) as the positive reinforcement ratio increased from 1% to 1.12%, 1.71%, and 1% solid beam, and the optimal ratio of steel fiber was 2%. [ABSTRACT FROM AUTHOR]

Different fields can profit by nuclear fragmentation cross section measurements: among them hadrontherapy and space radioprotection are of particular interest. Hadrontherapy employs high-energy beams of charged particles (protons and heavier ions) to treat deep-seated tumours. In these treatments nuclear interactions have to be considered: beam particles can fragment in the human body releasing a non-zero dose beyond the tumour while fragments of human body nuclei can modify the dose released in healthy tissues. On the radioprotection side, the interest in long-term manned space missions beyond Low Earth Orbit is growing in these years but it has to cope with significant health concerns from radiation in space, necessitating an accurate cross section data description. The FOOT (FragmentatiOn Of Target) experiment was proposed to cover these gaps in data. It was designed to detect, track and identify nuclear fragments and aims to measure double differential cross sections both in angle and kinetic energy which is the most complete information to address existing questions. The FOOT experimental setups, the experimental program and a first cross section analysis of 400 MeV/u 16O beam on Carbon target data acquired in July 2021 at GSI (Darmstadt, Germany) will be presented. [ABSTRACT FROM AUTHOR]

The assessment of steel corrosion in concrete is the global concern, particularly for RC structures in hostile environments. Despite a decade of rigorous research on steel corrosion in concrete, measuring corrosion technology continues to present. This study provided a comprehensive overview of corrosion evaluation using electrochemical methods, such as half-cell potential measurement, electrical resistivity of concrete, and rate of corrosion, after explaining the corrosion process. Half-cell potential measurement has proved a highly valuable, method of non-destructive for locating corrosion regions for monitoring, condition assessment, and estimating repair efficacy. The resistivity of concrete may reveal the permeable areas, where the penetration of chloride is most likely to be rapid and value of rate of corrosion in the future will be the highest; appropriate preventive action can be taken. Corrosion rates are classified as the average value and direct value of rate of corrosion. The average value of rate of corrosion is the medium for a long time period of measurement process by checking the weight loss or cross-sectional loss of steel bars. In contrast, the direct rate of corrosion can be measured electrochemically, specifically resistance of polarization tests. The goal of this work is not only to provide information on concrete corrosion assessment, but also to shed light on modern corrosion assessment techniques for accurate and rapid detection. [ABSTRACT FROM AUTHOR]

In the current study, the semielliptical beams were studied through bisecting them about their main major (long) axis. The finite element method was used to analyze fifteen reinforced concrete semielliptical beams. The parameters that were taken into account were beam height, concrete compressive strength, number of supports and the change of loading type from concentrated to uniform one. It was found that increasing height by 5.55-16.66% leads the positive, negative and torsional moments besides load capacity to increase by about 5.9 -21.7%, 5.9-19.6%, 6-19.6% and 5.9-19.8%, respectively. Positive, negative, torsional moments and load capacity increase by about 6.3-19.4%, 6.2-18.7%, 6.2-18.7% and 6.5-19.6%, respectively, while deflection decreases by 0.6-0.7% when the concrete compressive strength increases by 14.3-42.7%. When concrete compressive strength increase by 14-43%, the positive moments decreases by 24.27-10.12% when the number of supports was increased from 3 to 6. The negative and torsional moments besides midspan deflection and load capacity decrease by about 50.87-67.92%, 39.55-87.4%, 74.64-81.43% and 13% respectively when the number of supports increase from 3 to 6. When changing the type of loading from central concentrated to uniformly distributed one, the negative and torsional moments besides deflection increase by about 0.5-6.7%, 0.6-3.5% and 0.5-3.6%, respectively, while the positive moments decrease about 6.1-24.7%. When applying just 20% of the span length partially loading, the loading capacity increases about 128.3%, but it decreases by about 76% when applying 100% full loading of the span length. [ABSTRACT FROM AUTHOR]

This research investigated behavior of high strength reinforced concrete beam strengthened by CFRP sheet. Beam strengthening were carried out by using many techniques, externally bounded reinforcement (EBR), externally bounded reinforcement out of groove (EBROG) and externally bounded reinforcement inside groove (EBRIG). Eight beams were modeled with strengthening and compared with control beam. Tension and compression crack patterns, ultimate load, maximum deflection at mid span and equivalent deflection were investigated. Results showed that using CFRP sheet with 75 mm width increasing ultimate load about 15.8%, 26.50% and 30.17%. On the other hand, with 150 mm width about 19.86%, 30% and 43% for EBR, EBROG and EBRIG techniques respectively. However, deflection decreased about 80% whatever techniques were used. Finally, EBRIG method decrease deflection about (15%) compared with EBROG method. [ABSTRACT FROM AUTHOR]

There are two kinds of damages in concrete, the first is involved the structural damage which the reinforcement is affected while the second is related to one is related to the matrix of materials deterioration process. The interest in treating cracks has significantly increased, researchers were trying to find the alternative ways to treat cracks due to the interest of the cracks treatments were increased. Therefore, using bacteriological generated calcium, also known as calcium carbonate (CaCO3) deposition, new technology has been developed for the spontaneous treatment of cracks and cracks in concrete (MICP). The self-healing technology increases the strength of the concrete structure. This study presents review study of the Biomineralization methodology for improving the mechanical properties of concrete. It includes the comprehensive review for the theoretical and experimental ways that discussed the effect of Bactria on the concrete beams behavior. The self-healing technology increases the concrete structure strength. Studies have shown promising results in the use of organic and inorganic materials to seal cracks. [ABSTRACT FROM AUTHOR]

The aim of this research is to study the structural behavior of six self-compacting concrete box beam and evaluate the strengthening techniques and their impact on the structural behavior of the box beam under the effect of pure torsion. The strengthening techniques used in this study are: (steel plate, steel bracing, steel fiber, carbon fiber reinforced polymer (sheet and bar). All beam specimens have the same dimensions of (2200x350x350mm) for length; width and depth respectively, and (70mm) wall thickness, were casted and examined under pure torsion up to failure. The experimental work included two groups of beams in addition to one control beam. The first group comprised two beams with an internal Strengthening techniques such as (steel bracing and steel fiber (1%)), while the second group contained three beams with an external strengthening techniques by using (steel plate and carbon fiber reinforced polymer (sheet and bar)). The crack pattern, modes of failure, longitudinal deflection, and also measured and discussed the applied torque-angle of twist relationship at the end and mid span. The results of the experiment showed a significant increase in the ultimate torsional capacity strength by 37.7 %, 41.2 %, 72.9 %, 82.4 %, and 84.7 % for beam specimens strengthened by CFRP-bar, CFRP-sheet, steel fiber, steel plate and steel bracing, respectively, in comparison to the reference specimen. In addition, the adopted strengthening techniques have shown good efficiency in increasing the section tor-sional capacity in comparison to the reference beam. [ABSTRACT FROM AUTHOR]

In this paper, the structural behavior of hybrid reinforcement concrete RC beams with openings was investigated. Goals included evaluating the impact of utilizing Slurry Infiltrated Fiber Concrete SIFCON. The experimental program consists of casting and testing four beams, two of them cast with Normal Concrete NC completely (solid beam and beam with openings), while the other specimens were cast with NC and used SIFCON surrounding the openings (solid beam and beam with openings). Ultimate load capacity, load-deflection curves, and crack patterns were investigated in this research. Results show an improvement in flexural behavior and an increase in cracking load for specimens casting with SIFCON as compared with NC. It was found Even in the failure state, no vertical or horizontal cracks were seen at the interfaces between normal concrete and SIFCON in hybrid beams. This is a good sign that the casting technique utilized in the current investigation is effective. On the other hand, hybrid concrete beams with openings display great development in ultimate load by about (400%) as compared with specimen cast with NC-containing openings. [ABSTRACT FROM AUTHOR]

This paper looks into the behavior of beams with openings in shear zone strengthening with Carbon Fiber Reinforced Polymer (CFRP) sheets under static load. The experimental program included four simply supported beams, one of them without openings, one with openings (unstrengtheing beam), and two with openings strengthening with CFRP sheets. One of the beams was strengthening before a test and the other strengthened at 50% of the ultimate load. The ultimate load capacity, load-deflection curves, and crack pattern were investigated. The test results found that specimens strengthening with CFRP sheets surrounding the openings showed great enhancement in the ultimate load reach to 152.1% for beam strengthening with CFRP as compared with unstrengthening beams with openings, and delayed the appearance of cracks around the openings and diverted their path. Numerical modeling through the ABAQUS finite element program was introduced. The experimental and numerical study was found to have a high agreement. Parametric studies with different widths according to ratios 3.5%, 5%, and 6% which is (the area of the opening to the total area of the beam) were investigated. [ABSTRACT FROM AUTHOR]

As a part of study on recycled aggregate concrete (RAC) application on structural element, experiments on simple beam using Digital Image Correlation (DIC) results and numerical study results are presented. The experimental study involves a 3000 x 150 x 250 mm3 beam with semi-cyclic loading using DIC to investigate the load vs. deflection, strain, and cracking behavior, with comparison to measurement using LVDT and cracking formation on the sample. The numerical study is done in CAST3M using Timoshenko multi-fibre beam element with Mazars and Unilateral La Borderie concrete model along with PARFAIT_UNI for the steel model, with the objective of replicating the load vs. deflection graph and strain distribution of the experiment. From the experiment, the results for midspan deflection from DIC are similar with readings from LVDT and from the strain distribution the beam experienced flexural and inclined cracking during the loading phase, while majority of flexural cracking closed during unloading phase except two locations where permanent cracking has formed at yield limit. From the numerical study, Mazars and unilateral La Borderie concrete model along with PARFAIT_UNI steel model using multi-fibre Timoshenko beam element could approach the load vs. deflection graph of the experiment using monotonic loading. On the other hand, the numerical model shows less residual deformation and higher load capacity during loading-unloading cycle using semi-cyclic loading. The Numerical model strain distribution obtained using unilateral La Borderie concrete models cannot show specific location where cracking happens, but it can show the area where cracking will likely be distributed. [ABSTRACT FROM AUTHOR]

Steel bars that are commonly used in RCC structures are subjected to corrosion due to atmospheric conditions and other calamities at critical temperatures. To avoid corrosion, it is necessary to find an alternative source for steel reinforcement. For the investigation purpose materials especially G.I.Pipes and GFRP rods havechoosen. G.I pipes have better corrosion resistant property as it will resist corrosion. GFRP rods will eliminate major repair problems that arise due to steel reinforcement and have high load carrying capacity. In order to investigate the performance of these materials on RC Structures steel roads are replaced by G.I Pipes and GFRP rods fully and partially. Beams of cross section (150x200) mm of span 1500 mm were casted. M35grade concrete is used. The casted beams are cured for about 28 days. Among them, one beam is casted using steel reinforcement, one beam is of partial steel and GI pipe reinforcement, one beam is of partial steel and GI pipe reinforcement, one beam is of fully G.I Pipe reinforcement, one beam is of partial steel and GFRP rods and one beam is of fully GFRP rods. The Specimens are tested in loading frame after curing process. Among the tested specimens, the beam which is casted with partial steel and GFRP rods shows better outcome than the other specimens. [ABSTRACT FROM AUTHOR]

Infrastructure building has accelerated tremendously during the last century. Concrete is crucial to this growth since it is used extensively in constructing various structures in everyday life. Among all building materials, concrete is the only one that was purposefully designed and had unique qualities. Due to its longevity and great compressive strength, it is the most used building material in the construction industry. Owing to the rising industrial need for concrete, scientists and researchers are researching alternative binder materials that are environmentally friendly and assist in organizing agricultural excess, mostly sugarcane ash. The article explores the use of sugarcane bagasse ash in concrete to increase the industry's sustainability. The concrete beams are tested for the effects of shear and flexure. Additionally, the report gives valuable information for durability investigations and microstructural analyses. [ABSTRACT FROM AUTHOR]

The coupling member, coupling beams are characterized by large deformations and shear-dominated responses. To accurately evaluate the magnitude of the seismic response of the buildings with the coupled shear walls, the model must be the one that includes the parameters that are expected to influence these responses. In this study, using the constructed database of prior studies, the formulation is proposed to determine the nominal shear strength of the Fiber Reinforced Composite coupling beams. Three samples of the diagonally reinforced concrete coupling beam specimens: one sample with fiber reinforcement composites and two samples without fiber reinforcement composites are analytically modelled. The time history nonlinear direct integration modelling method by using SAP2000 is used to evaluate the energy dissipation capacities of the coupling beams. To accurately evaluate the performance of diagonally reinforced coupling beams under reversal cyclic loadings, the strength and the chord rotation capacity of each specimen as a function of the parameters that are used in each sample is used in this study. Results show that the chord rotation capacity that is exhibited by the specimens with FRC is much less than that exhibited by the concrete without fiber reinforcement. And at the end, the diagonal bars also perform less at a higher aspect ratio, and hence this significantly decreases the shear carrying capacity of the coupling beam. [ABSTRACT FROM AUTHOR]

The paper investigates the influence of steel fibers on the bearing capacity, deformability and fracture resistance of the supporting sections of bending elements. Beams of rectangular cross-section of two series-reinforced concrete beams of ordinary concrete and beams of combined reinforcement using steel fibers were considered. To make the specimens of the second series, steel anchored fibers were evenly added to the concrete, the total volume of which was 1% of the mixture volume. A special force bench was assembled to test the beams. During the tests, the load applied to the beams, deflections and deformations of individual concrete fibers were recorded. The load was applied in steps of 0.05 of the destructive load, the value of which was determined in the process of preliminary test loads. The carried out researches showed that the bearing capacity of the beams of combined reinforcement was practically by 50% higher than that of the conventional reinforced concrete beams. The breaking load in combined reinforcement beams is 162kN, and in conventional reinforced concrete beams 112kN. The deflections in steel-fibercrete beams by the time of failure are 1.4 times less than in reinforced concrete beams. The relative tensile deformations of concrete fibers in the shear span at the moment of failure are 3 times higher than those in the pure bending zone. [ABSTRACT FROM AUTHOR]