openings at the flexure zone. Selected beams were strengthened using TextileReinforcedConcrete (TRC) wraps. A total of six beam specimens measuring 250 mm (height) x 200 m (width) x 1700 mm (length) were cast using high strength concrete with a compressive strength of 64 N/mm 2 . The beams tested consisted of a solid control beam, unstrengthened concretebeams with openings and strengthenedconcretebeams with openings. The effect of circular and square openings on the flexure zone of concretebeams was investigated. All the beams were simply supported and tested up to failure under four-point loading. From the test results, it was found that the presence of openings at the flexure zone significantly reduces the strength and stiffness of the beams. The use of TRC wrap around the beam openings increases the ultimate capacity and stiffness of the beams. In addition, it also reduces excessive vertical cracks and deflection in beams considerably compared to unstrengthened concretebeams with openings.
TextileReinforced Mortar (TRM) has recently been introduced in the construction industry as a viable alternative strengthening material, to circumvent problems associated with FRP. They are made of fabric grids and a cementitious agent which serves as a matrix and binder. The cementitious matrix used in TRC system has high thermal capacity and better compatibility with the concrete substrate compared to those of the epoxy resin used in FRP. The use of TRC composites for strengthening and repair of reinforcedconcrete structures, though relatively recent, is gradually gaining popularity as an alternative to FRP . TRM is a composite material consisting of a matrix with a minimum aggregate size between 1 and 2mm. Textiles are fabric meshes made of long woven, knitted or even unwoven fibre rovings in at least two (typically orthogonal) directions. The quantity and the spacing of rovings in each direction can be controlled independently, thus affecting the mechanical characteristics of the textile and the degree of penetration of the mortar matrix through the mesh openings . It is through this mechanical interlock that an effective composite action of the mortar-grid structure is achieved.
Engineer we all know that Concrete is strong only in Compression and weak in Tension. In order to increase the Tensile strength of the Concrete, it is being reinforced with steel, which unfortunately also has the drawback of being susceptible to corrosion and fatigue. It will further increase the maintenance and repair cost of the structure. And it is clear that we urgently need high performance construction materials to adequately meet our needs. An innovative concept to eliminate these drawbacks is the textile reinforcement of concrete. For past many years leading scientists have been working with the idea of improving the world of concrete by using high performance fibres, developing so called “TextileReinforcedConcrete (TRC)”. The objective of this project is to study the various properties of TextileReinforcedConcrete (TRC). AR-Glass fibre mesh of 145 GSM is used. Specimens were casted with and without the fibres in the range of increase of fibre layers of 3, 4 and 5. Tests were conducted to study the Flexural strength of the beam. Beam specimens were casted using the 500mm×100mm×100mm beam mould. Among 4 beams casted, 3 were casted with fibre mesh and the another beam were casted without fibre mesh i.e. PCC beam. The tests were conducted by the method of three point loading system on the beam. And the interaction between the Cementitious Matrix and the Textile fibre mesh were determined. The results are compared between TextileReinforcedConcrete (TRC) and the Conventional Concrete. In which the PCC beam shows the Modulus of Rupture value as 7.75 N/mm 2 ,
slip behaviour between FRP sheets and concrete. According to Sebastian  and Teng, et al , the corrosion of longitudinal steel bars and the change of the reinforcing bar ratio in the vicinity of large bending moments, shear forces increase the probability of these types of failures. When FRP reinforcement is being used to increase the flexural strength of a member, it is important to verify that a member will be capable of resisting the shear forces associated with the increased flexural strength. To avoid failure type 5, the potential for shear failure of the section should be considered by comparing the design shear strength of the section to the required shear strength. If additional shear strength is required, FRP laminates oriented transversely to the section can be used to resist the applied shear forces.
All beams tested under fatigue loading were first loaded manually up to the maximum load, and then the load was decreased to the mean load before load cycling commenced. For all the unwrapped beams, flexural cracks appeared at both ends of the lap splice and within the constant moment region during manual loading to the maximum load. Within a few cycles of loading, random flexural cracks appeared outside the constant moment region. The flexural cracks grew vertically and diagonally and stopped growing at about 80% of the beam depth. During the first cycle, splitting longitudinal cracks occurred on the bottom face at both ends of the lap splice. Then the cracks continued to grow with cycling until failure. The splitting cracks grew in width until failure occurred. The rate of growth of the splitting cracks increased as the applied load range increased. At the failure, the splitting cracks traversed the entire lap splice length as shown in Figure 4.14. The concrete in front of the steel bar lugs was clear without any abrasion as shown in Figure 4.15. The concrete chunks were larger for the small concrete cover than for the larger concrete covers as shown in Figure 4.16. The failure of all unwrapped beams was by a bond splitting failure between the concrete and the steel bar.
Five reinforcedconcretebeams were casted in this study. One beam was a control specimen (no opening and not strengthened) while another four beams were casted with circular and square openings. All beams have a cross section of 200 mm width, 250 mm height and an effective length of 1.7 m. The size of square opening is 124 x 124 mm while the diameter of circular opening is 140 mm. All beams were designed to fail in bending. For flexure reinforcement, two reinforcing steel bars of 12 mm high tensile steel were used as a tension reinforcement. The shear reinforcement consists of 6 mm stirrups spaced at 100 mm for the entire span. Fig. 1 to Fig. 5 show the reinforcement details of tested beams and Table 1 shows the summary of specimens. Beam B1 is the control specimen, beam B2 is un-strengthened beam with square opening, beam B3 is un-strengthened beam with circular opening, beam B4 is beam with square opening strengthened using CFRP sheet and beam B5 is beam with circular opening and strengthened using CFRP sheets. Each CFRP sheets applied was in the form of U-wrap which is around the three sides of the beam except the top-side area.
In this study, nine pretensioned prestressed concretebeams were made and tested, two of which were without openings as a control beams (one without and the other with strengthening by CFRP sheets), three were with openings, and the remaining four with openings and strengthened with CFRP sheets. The prestressed concretebeams designed according to ACI code 318-2011 class C. In all beams specimens the cross section was (b=130mm, H=300mm), the overall length was 2000mm, with clear span 1800mm and shear span 700mm. One strand Φ15.24mm (7-wire) and (2Φ12mm) diameter used as longitudinal reinforcement at bottom and (2Φ12mm) diameter bars used as longitudinal reinforcement at top to resist tension stresses at initial stage. The flexure prestressed beams designed with extra strength in shear ( used Φ10mm stirrups at 70mm center to center) to ensure flexure failure even after strengthening as shown in Figure(6). Strengthening system was chosen carefully according to some considerations, mainly, crack pattern around of opening and mode of failure. Five beams prepared and strengthened with CFRP sheets as shown in Figure (7). The beams FBCSt, FBO1St, FBO2St and beam FBO3St were strengthened in tension zone with one layer of longitudinal CFRP (width 130 × length 800)mm and in compression zone with full wrap CFRP (width 800)mm, while the beam FBO3StC was strengthened in compression zone only with full wrap CFRP (width 300)mm at top chord of opening. More details for the beams specimens were shown in Figure (7) and Table (5).
The beam specimens were placed in the universal testing machine of capacity 600kN and all the beams were tested under two-point loading. The beam is placed in one roller and one hinged supports, resting on iron blocks placed on wing table of the testing machine, the load is from the fixed cross head of the machine as two point load. Deflectometer were fixed at the midspan to measure the deflections. The beam was gradually loaded by increasing the load at each cycle. The beam was loaded till failure and first crack and ultimate load stage were noted.
The hydration reaction of concrete, that was briefly discussed at the start of this section, may provide some insight as to why the parameters discussed in this paragraph contribute to a material that exhibits a higher resistance to fatigue. Concrete with high cement content, low water-to-cement ratio and that had been adequately cured and aged is likely to be highly impermeable (H. Beushausen et al., 2019). That is permeability in terms porosity of concrete as well presence of shrinkage crack. With that in mind, a concrete matrix with a lower density of voids and openings will require more energy, in the form of applied load, to induce cracks that can then propagate under repeated cyclic loading. Moreover, if enough energy is induced in the material to cause fracturing, the presence of fibrous material in the material matrix may prolong the deceleration phase of fatigue crack growth (K. Kim et al., 2017). Bridging materials such as steel fibres or fibrous fly ash have been shown to reduce the effects of shrinkage cracking (Shetty, Venkataramana, & Narayan, 2014) and may therefore influence the fatigue of both concrete and patch repair mortars.
Flexural and shear failures are the main critical failure patterns of the RC members. Flexural failure of under-reinforced sections is ductile and develops progressively with significant cracking and displacements, which show a warning of failure. On the contrary, shear failure is extremely brittle and does not allow significant redistribution of shear forces; therefore, shear failure develops without warning and is usually disastrous. Shear-deficient beam failed in shear prior to achieving the full flexural capacity. Thus, RC structures should have sufficiently more margin with regards shear capacity when compared with flexural capacity. Therefore, retrofitting and repairing of the reinforcedconcrete members could be required to improve the shear capacity of the reinforcedconcrete structures. Structures that are deficient in shear can be strengthened or repaired by using FRP composites (Bellamkonda, 2013). Many experimental and theoretical studies have been conducted regarding the shear strengthening of normal weight reinforcedconcrete (NWRC) structures retrofitted externally with FRP. Limited studies were found in the literature review for FRP strengthening of lightweight reinforcedconcrete (LWRC) structures tested for shear failure, in spite of the shear capacity of lightweight concrete (LWC) being lower than normal weight concrete (NWC).
Carbon fibre has very high tensile strength and is also very lightweight. When it bonded to the exterior of a concrete column, beam, or slab, it can add significant strength without adding weight that would increase the load on foundations and other structural members. Carbon laminate is a stiff composite plate use to enhance the flexural and moment enhancement for structure. It is available in Rolls of 100 m, 150 m, or cut to size. An unwinding reel is available upon request. Special dimension upon Request. Its elastic modulus is 260 kn/mm 2 and tensile strength is 3900 n/mm 2 .
Transverse opening in a reinforcedconcrete beam allows the crossing of mechanical and electrical services through the beam. However, it affects the strength of a beam. Understanding its structural behaviour is crucial to ensure a safe design of the beam. For that, an experimental study was carried out on reinforcedconcretebeams with circular transverse openings. The four-point load test was conducted to study the effects of the size and the position of the opening on the beam performance under the shear and flexural loads. In addition, three reinforcing methods for the opening were tested. The beams were evaluated in terms of the load-displacement responses, mechanical properties, deflections, and failure modes. The opening with the diameter not exceeding 0.25 times beam height affected about 20% of beam strength (without reinforcements at the opening). The diagonal bar reinforcing method effectively restored the beam strength for the opening size not exceeding 1/3 of beam height. The equation model proposed conservatively predicted the ultimate capacity of the beam with a transverse opening.
caused a high reduction in the shear capacity of the beams by about 35%. In addition, the strengthening of openings contains the cracks and increase the crack and ultimate load. Finally, they recommended, the openings should be kept away from the load path connecting the loading and support point. If the openings were far from the natural load path, e.g. within the mid-span region, the results indicated that the opening effect becomes minimum. Therefore, these regions are suitable for providing openings when required. In (2017) Al-Mutairee  tested sixteen specimens under two-point loading to study the flexural behavior of reinforcedconcrete continuous deep beams made of normal strength concrete, hybrid concrete, and high strength concrete at different percentage and location and their strengthening by CFRP. The main variables studied were the high strength concrete layer thickness and CFRP on the deep beams strength. The test results showed that the strengthening of continuous deep beams by high strength concrete layer from top was more effective than from bottom. The optimal layer thickness percentage was 25% of the total depth of beams. Also, the strengthening of hybrid continuous deep beams by CFRP strips at bottom for flexural increased the load capacity.
To carry out studies some experimental investigations were done on behaviour of RC beamsstrengthened in flexural and shear by means of GFRP laminates. Outwardly epoxy-bonded GFRP sheets reinforcedconcretebeams were tested to failure using a two point concentrated static loading system. For this experimental investigation three sets of beams were casted test program. In first set of three beams were casted which were weak in flexure, among them one was controlled beam and rest two beams were strengthened by means of continuous glass fiber reinforced polymer (GFRP) sheets in flexure. For second set, three beams were casted but they were weak in shear, and again among them one was the control beam and left over two beams were strengthened by means of continuous glass fibre reinforced polymer (GFRP) sheets in shear. For third set, three T beams were casted, having one controlled beam along with two beams which were strengthened with GFRP Different amount and configuration was to strengthen the beams with the help of GFRP sheets. For each of the beams experimental data for load and their corresponding deflection were recorded. Also the detailed procedure and their application for strengthening RC beams are included. The orientation of GFRP layers and its effect of number on ultimate load carrying capacity is studied along with this failure mode of the beams are investigated
The beams were testing under Two point bending loading. In this case there is constant maximum moment and zero shear force acting in the section between the loads. Between the supports and loads linearly varying moment acts. Spacing between the supports is 1000mm and is applied at points dividing the length into three equal parts plates are used under the loads to distribute the load over the width of the beam. The testing equipment is a universal testing machine of 100KN capacity. Flexural strength of beams are calculated by using this formula
Considering the load-deflection diagram of the beams, it is clear that, the specimens with truss reinforcement is better than control specimen where the deflection is less for truss reinforcedbeams. Thus it can be concluded that, change in the pattern of reinforcement from vertical to inclined, increases the stiffness and strength of the beam. That is, the inclined diagonals of the truss reinforcement contributed to increased flexural strength of the beams. Whereas, the difference in inclination of the diagonals in truss reinforcement do not have any effect in the failure mode or load carrying capacity of the beams as they shows similar load-deflection pattern.
A solid element, SOLID65, is used to model the concrete in ANSYS. The solid element has eight nodes with threetransitional degrees of freedom at each node. In addition, the element is capable of simulating plastic deformation, cracking in three orthogonal directions, and crushing. The steel plates at the supports for the beams are modeled using Solid185 elements. This element has eight nodes with three degrees of freedom at each node – translations in the x, y, andz directions. In order to obtain the internal strains in the reinforcement bars and keep them in their right positions, the discrete technique using the 3D spar Link180 element is followed. This element has two nodes with three degrees of freedom translations in the x, y, and z directions. This element is also capable of plastic deformation.
geopolymer concrete and this has been the key motivation of this undertaking. This study presents an investigation of the flexural response of geopolymer concretebeamsreinforced with sand-coated glass FRP (GFRP) bars subjected to four-point static bending test. Three full-scale beams with nearly same amount of bottom GFRP bars but with varying diameter were cast and tested. The crack patterns and failure modes, load versus deflection relationships, bending-moment and deflection capacities, and strains in the bars and geopolymer concrete are presented. Furthermore, the experimental flexural capacity of beams are compared with the predicted values using the current standards and with their GFRP- reinforcedconcrete (GFRP-RC) counterparts to verify the suitability of the proposed system for structural applications.
Reinforced Polymer (CFRP), and Aramid Fibre Reinforced Polymer (AFRP), are compared with the modulus of common reinforcing steel as in Figure 1.4, the major differences become apparent. While the stress strain curves vary between the fibres, none of the FRP material has a higher elastic modulus than steel. Table 1.1 shows the comparison of average strength and modulus values for the commonly used fabrics, and this difference in modulus becomes apparent. However, while the initial modulus is less than that of steel, due to the linear stress-strain which these FRP materials experience and the lack of a yield point, these fabrics can reach much higher stresses before failure. This can be a great advantage over steel when rehabilitating and strengthening reinforcedconcretebeams, if the proper precautions are taken to ensure there is no brittle failure.
eccentric load was applied using the wedge and plate assembly.The theoretical spanl of the tested beamsis equal to 3000mm. Each specimens were positioned in between the saddle supports on torsion testing equipment with two eccentric arms cast with wedges to hold on both sides of the specimen with identical eccentricity of e= 350mm to ensure, as far as possible pure torque along the span.The ends of the beams are provided with a wedge to hold the wedge plate attached to the torsion testing machine. Also wedge plates are provided at the ends of the beams to ensure uniform torque transmitted to the beam cross section.All beams are reinforced with 12 mm diameter as longitudinal reinforcement and 8mm diameter as transverse reinforcements as shown in Fig.1. The c/c spacing of the transverse reinforcements are equally spaced along the span.The longitudinal steel ratios are 0.56 and 0.86. The cover of 20 mm (d c ) was provided for the specimens. All the