Amount Of Reinforcement Research Articles

Assessment and strengthening of reinforced concrete bridges with half‐joint deterioration

AbstractExisting Niagara‐type concrete cantilever bridges, which in Italy are called Gerber bridges, suffer from degradation due to reinforcement corrosion and a consequent reduced load‐bearing capacity. The assessment of these structures is therefore an important part of the procedures for analyzing the state of existing bridges and any interventions required for their retrofitting. In particular, safety against failure of the half‐joint must be evaluated with respect to the behavior of the entire bridge and its state of conservation, determining what the conditions are that lead to failure, in terms of loads, state of stress, and possibly cracking state. This evaluation has to be carried out considering the configuration of the bridge through local and global models, in the presence of the crossbeam between the main girders or the prestressing tendons that can modify the behavior of the Gerber saddle, compared to that expected for a simple dapped‐end beam. To do this, it is necessary to combine the in situ investigations with reliable analytical and numerical models, which can correctly interpret the structural behavior of the bridge, determining the critical aspects for safety. The approach followed in this study was to combine the strut‐and‐tie models with nonlinear finite element models that can provide reliable information to the engineer who deals with the assessment and subsequently the conception of rehabilitation, in combination with in situ investigations and material tests. This was carried out through two different case studies in which the shape of the Gerber saddle, the presence of the crossbeam, and the presence of prestressing characterize the behavior and highlight the degree of safety and that of structural robustness. The results of the analyses carried out show that the presence of prestressing and a careful design with the use of large amounts of reinforcement can lead in some cases to high safety factors and consequently to a good level of robustness. They also show that the structural behavior can vary significantly according to the level of reinforcement corrosion: this is an aspect that can only be correctly assessed with the use of different models with different degrees of refinement. Finally, a proposal for global structural rehabilitation is presented by closing saddles, changing the static scheme to the continuous beam, and supplying external prestressing to strengthen the deck.

Use of fiber reinforced concrete in bridges – Metrorrey Line 2 case study

An assessment concerning the structural applicability and performance of fiber reinforced concrete (FRC) is presented for different bridge elements and within a design framework. FRC as the main bearing material in structural members has evolved from low-demand applications to increasingly ones, where bending and shear are the main internal forces. In actual applications, this was reflected with initial slab-on-grade cases, through tunnels, and later moving towards elevated slabs. Past experiences show that FRC has notable features regarding ultimate capacity and serviceability performance (i.e., enhanced crack control). These capabilities allowed for optimizations such as material savings, reduction of intensive labor during construction, or extended durability. Considering FRC's enhancements from previous applications, a case study based on the Metrorrey Line 2 light-train viaduct (Mexico) is developed. The case study aims to assess the structural performance that FRC can deliver within bridge geometries, loads, and specific conditions. Two numerical models considering different transversal post-tensioning configurations are developed based on the reference structure. The use of these two numerical models aims to broaden the applicability of this study to most U-shaped light-train viaducts. The design is based on current and future standards and recommendations, being prEN1992-1-1:2021, EN1992-1-1:2004, and fib Model Code 2010. After the numerical models and structural analysis, different sectional analyses at ultimate and serviceability levels are carried out, considering both conventional and fiber reinforced concretes. From the sectional results, FRC can provide reductions to reinforcement quantities at ultimate load levels, which are tied to the initially required reinforcement ratio (in other words, linked to the internal forces existing in the element). When higher reinforcement ratios are necessary, FRC optimizations point toward serviceability limit states, especially on the crack width reduction and the potential to reduce or suppress any additional reinforcement due to crack limitations.

Mechanical investigation and design of axially-loaded concrete columns reinforced with grade 700 MPa reinforcing bars

The utilisation of high-strength steel rebars is meaningful for saving iron ore resources and reducing engineering costs, which is extremely important for developing a green low carbon society. However, the research on the performance of the concrete column reinforced with rebars over 600 MPa yield stress is quite limited. To fill up this gap, this paper introduces a novel high-strength hot-finished rebar offering yield stress of about 700 MPa (HSR700) and conducts an experimental study of axially-loaded concrete columns reinforced by normal-strength rebars (RC-NSR) and HSR700 (RC-HSR700). Refined numerical modelling is developed and verified by selecting proper concrete models and modifying the element type. Detailed mechanical analyses on the potential failure modes, the confinement state of the concrete and the bending behaviour of the longitudinal rebar are performed to figure out the compatibility behaviour between the concrete and HSR700 bars. A following systemic parametric investigation is developed to explore the impacts of material and geometric parameters (i.e. the amount of longitudinal and transverse reinforcements) on the axial compression performance of the RC-HSR700 short columns. The research results indicate that the load-bearing capacity and deformation ability of the RC columns evidently increase with the use of HSR700. In respect of the compatibility, the strength utilisation of HSR700 longitudinal bars can be gradually improved by 29.5 % when the volumetric ratio of the transverse reinforcement increases from 0.67 % to 1.26 %, but the utilisation degree hardly correlates positively with the concrete strength. Finally, calculation methods for assessing the deformation feature of the longitudinal reinforcement and the axial compression strength of the RC short columns are presented considering the compatibility behaviour between the concrete and HSR700 bars. The research may offer a scientific basis for the application of RC structures using high-strength rebars.

Different Fiber Reinforcement Effects on Fly Ash-Based Geopolymer Long-Term Deflection in Three-Point Bending and Microstructure

This study investigated the effect of a low amount of polyvinyl alcohol (PVA) and steel fiber reinforcement on fly ash-based geopolymer composite long-term deflection and its microstructure. For testing purposes, specimens with different amounts and types of fiber reinforcement as well as plain (reference) were prepared. The long-term deflection test was performed by loading specimens with 40% of the ultimate flexural strength. A microstructure analysis was performed using polished section specimens, and images were acquired at 25-times magnification on a scanning electron microscope. The results of the flexural strength test show that all geopolymer composites with fiber reinforcement have lower flexural strength than plain geopolymer composites. The long-term deflection tests show that the highest deflections exhibit 1% PVA fiber-reinforced specimens. The lowest amount of deflection is for 1% steel fiber-reinforced specimens. Specific creep shows similar results to plain, and 1% steel fiber-reinforced specimens, while 1% PVA and 0.5% PVA/0.5% steel fiber-reinforced specimen exhibits the same properties. The quantitative microanalysis of the polished section further confirms the deflection results. Specimens with 1% PVA fiber reinforcement have significantly higher porosity than all other specimens. They are followed by plain specimens and 1% steel fiber, and 0.5% PVA/0.5 steel fiber-reinforced specimens have almost the same porosity level.

Shear behavior of composite stone beams reinforced with NSM longitudinal CFRP bars

Employing near-surface mounted (NSM) carbon fiber reinforced polymer (CFRP) bars in the tensile zone of bare stone beams can effectively improve their flexural performance. Meanwhile, shear failure could occur when excessive amount of flexural reinforcement is adopted. Seven composite stone beams were tested to study the shear behavior of composite stone beams reinforced with NSM CFRP bars. The test variables included the shear span to depth ratio and the reinforcement ratio. Digital Image Correlation (DIC) technology was used to capture the full-field strain of the beams. The results indicated that the composite stone beam exhibited ductile failure mode with visible deflection and multiple cracks formed in both constant bending zone and flexural-shear zone. With the decrease of shear span to depth ratio, the cracking load and shear capacity increased linearly but the deformation capacity decreased. For the same shear span to depth ratio of 2.5, the composite beam with a higher CFRP reinforcement ratio observed higher shear load-carrying capacity. DIC results demonstrated the shear force was mainly provided by the arch action before failure. A shear-resistance theoretical model based on Rankine's failure criteria, sectional mechanical analysis and experimental observations was proposed and verified with the current and previous test results.

Effect of connection transverse reinforcement on the behavior of GFRP-RC T-connections: Numerical investigation

This study numerically investigates the cyclic behavior of glass fiber-reinforced polymer (GFRP) reinforced concrete exterior beam-column (T-BC) connections (GFRP-RC T-BC connections) with varying amounts of transverse reinforcement (TR) in the connection panel. The amount of TR required to provide adequate confinement and shear strength to the GFRP-RC T-BC connections has not yet been fully understood. The primary objective of this study was to evaluate the effects of TR configuration and amount of TR on the load-drift ratio response, strain distributions and shear strength of the GFRP-RC T-BC connections. The numerical investigation was conducted using the numerical models developed in ATENA software and validated against the test results of four T-BC connections (one steel-RC and three GFRP-RC). The TR ratio and TR configurations (2 leg, 3 leg, and 4 leg horizontal stirrups) in the connection panel were the main parameters of the numerical study. Results of the numerical study indicated that increasing the TR ratio in the connection panel to 0.72% significantly enhanced the peak load, stiffness and drift ratio capacity of the GFRP-RC T-BC connection. Four leg TR configuration showed significantly better performance of the GFRP-RC T-BC connections due to the higher confinement factor than the other TR configurations. A shear strength equation was proposed for the GFRP-RC T-BC connections, which represents a linear relationship between shear strength and the TR ratio up to 0.60%, followed by stable shear strength of 0.85fc′ for a TR ratio up to 1.30%.

Nanosize Al2O3 reinforcement in Si-rich aluminum MMC for enhanced tribological performance in engine components

Aluminum metal matrix composites are increasingly popular nowadays because of their wide range of uses. The low weight and excellent mechanical qualities, such as strength and hardness, of Al-Al2O3 composites make them useful in many fields, including automotive, aerospace, electronics, aeronautics, and military. Most of the engine components are made of aluminum-silicon alloys because of their excellent casting and forming properties. In engine components wear is a crucial parameter to be considered therefore in this investigation Al-Si alloy with varying percentages of V2O5 has been considered to develop the Al-Al2O3 composite and evaluate its tribological aspect. For composite development, a novel in-situ approach has been used with the help of the stir-casting method. The tribological behavior of the different composites was examined experimentally and studied with sliding distance, applied load, and the amount of reinforcement. Composites show a significant increase in hardness relative to the base alloy because of the generation of hard alumina particles within the melt. The wear behavior of in-situ Al-Al2O3 composites was studied using a pin-on-disc setup. In terms of COF and wear rate, the composite with a 1% addition of V2O5 performed better in the trial.

Nano SiO2 doping effect on physicochemical properties of PVA-starch bionanocomposite films

In this study, starch-PVA based composite films combined with nano SiO2 were prepared by a solvent casting technique. Different amounts of nano SiO2 additives were added to starch-PVA films and the results were evaluated. Accordingly, in starch-PVA films containing nano SiO2 added in the ratio of 1%, 3%, and 5% by mass, nano SiO2 was homogeneously distributed on the surface of the composite films. However, loss of elasticity was observed in films from containing 3% nano SiO2 onwards. The unique properties of nanocomposite films obtained with small amounts of nanomaterial reinforcement have been demonstrated. Composite films have been characterized by Fourier-transform infrared spectroscopy, UV–Vis spectrophotometry, and field emission scanning electron microscopy. Fogging tests were compared. Less nano SiO2 additive in the samples showed the best anti-fogging behavior. This study aims to demonstrate the potential use of starch-PVA nanocomposite films with unique properties in food packaging applications. The surface of starch/PVA films is strengthened by the deposition of SiO2 nanoparticles.

The Behavior of Hybrid Fiber RC Shear Walls Subjected to Monolithic Pure Torsion: An Analytical Study

The reinforced concrete (RC) shear walls are widely used to serve as the primary lateral load-resisting member in the high-rise buildings. An experimental investigation and analysis of the mechanical behaviour of hybrid fiber reinforced self-compacting concrete (HFRSCC) shear walls under pure torsion moment is presented in this paper. The nine HFSCC shear walls with the same height and longitudinal reinforcement ratio analytically were tested under pure torsion moment and no axial load. The effect of hybrid fiber ratio and horizontal reinforcement amount and aspect ratio on the failure characteristics, torsional behaviour, energy dissipation capacity of squat shear walls was studied. Result indicate that both hybrid and horizontal reinforcement ratio are increased the maximum torsional moment capacity and twist angle and that the hybrid fiber ratio is the key parameter that determines the failure mode of the HFSCC shear walls.

On the Residual Static and Impact Capacity of Shear-Reinforced Concrete Beams Subjected to an Initial Impact

Impact loads in previous research showed to induce brittle responses of statically flexure-critical reinforced concrete (RC) beams designed for ductility. The impact load may produce flexural shear damage modes similar to that observed during quasi-static loads and local shear damage under the impact zone. The occurrence of shear damage modes during impact tests has been investigated extensively, but their effect on the residual quasi-static and dynamic capacity is not fully understood. For this aim, an initial high-velocity impact test initiated severe shear damage to RC beams. The beams were then tested quasi-statically and by sequential impact testing using the same setup as the initial tests. The results indicate a flexure-dominated response during sequential impact tests for beams containing extreme shear reinforcement amounts, favouring the energy-absorption capacity. Significant shear and flexural damage occurred for beams with less shear reinforcement, indicating a hybrid response that varied throughout the tests. The tests for the residual quasi-static capacity indicated severe consequences from initial local shear damage on the capacity, as shown by the brittle response of the beam with the most shear reinforcement. However, wide initial flexural cracks instead showed a favourable effect, as there was an indication of transfer from brittle to ductile failure. For beams showing both global and local shear damage, it was concluded that global shear damage modes were critical for the residual static and dynamic shear capacity.

Dynamic response of moderately thick graphene reinforced composite cylindrical panels under the action of moving load

An attempt is made is this research to study the response of cylindrical panels subjected to a moving load. Cylindrical panel is made from a composite laminated material where each layer of the media is reinforced with graphene platelets. Also the amount of graphene platelets in the layers may be different which results in a piecewise functionally graded media. With the aid of the first order shear deformation theory of shells, Donnell type of kinematics and Hamilton principle, the basic components of energies in the panel are established. With the aid of general idea of Ritz method whose shape functions are constructed using the Chebyshev polynomials, the matrix representation of the governing equations is established. While the developed formulation is general and may be used for moving load with arbitrary path and velocity, here it is assumed that velocity of the moving load is constant and load is passing on a straight line. The obtained equations are traced in time domain via the Newmark time marching scheme. Results of this study may be used for cylindrical panels with arbitrary combinations of boundary conditions. At first convergence and comparison studies are given to assure the validity of the proposed solution method and formulation. After that, novel numerical results are given to explore the effects of different parameters. It is shown that with introduction of even a low amount of reinforcements, dynamic deflections in the panel may be alleviated significantly.

The Pure Torsional Behavior of Hiybrid Fiber RC Shear Walls

The reinforced concrete (RC) shear walls are widely used to serve as the primary lateral load-resisting member in the high-rise buildings. An experimental investigation of the mechanical behaviour of hybrid fibre (carbon and steel) reinforced self-compacting concrete (HFRSCC) shear walls under pure torsion moment is presented in this paper. The nine HFRSCC shear walls with the same longitudinal reinforcement ratio were tested under pure torsion moment and no axial load. The effect of hybrid fibre ratio and horizontal reinforcement amount and aspect ratio on the failure characteristics, torsional behaviour, energy dissipation capacity, ductility of shear walls was studied. Results indicate that both hybrid and horizontal reinforcement ratio are increased the ultimate torsional moment capacity and angle of rotation and that the hybrid fibre ratio is the key parameter that determines the failure mode of the HFRSCC shear walls. Torsional moment capacity increased, when the hybrid fiber ratio rose up from 0% to 1.0% and then 1.5%. However, this increase was larger in case of increasing the hybrid fiber ratio from 0% to 1.0%. Increasing the hybrid fiber ratio from 1.0% to 1.5% did not result in a performance increase as in the first case.

Effect of type, amount and configuration of reinforcement in HSC box-girders reinforced with BFRP bars and steel stirrups under torsion-shear-bending

There has been no research on the performance of high-strength concrete (HSC) hollow members reinforced with basalt fiber reinforced polymer (BFRP) bars and steel stirrups under combined torsion (T), shear (V), and moment (M); this study examines the above scenario. Six specimens of identical size and length were constructed and tested, each having a total quantity of reinforcement of 2.5%. The supports were restrained against twisting and the load was applied at a transverse eccentricity of 1.67 m at midspan, producing the required T-V-M ratio, with torsion as the dominant action. The proportion of longitudinal to transverse reinforcement, the number and diameter of longitudinal BFRP bars, and the diameter and spacing of steel stirrups, were the factors investigated. The experimental results were evaluated in terms of strength and stiffness, deflection and angle of twist, cracking pattern, and failure modes. For the same total amount of reinforcement, the best results were achieved utilizing specimens with BFRP bars and steel stirrups of smaller diameter at closer spacings. Employing more longitudinal BFRP bars ( ρ l = 1.58 ρ t ) produced better outcomes than using more steel stirrups ( ρ t = 1.32 ρ l ), indicating that the amount of BFRP bars is as critical as or more important than the amount of steel stirrups. The experimental results of cracking torque and twist, and ultimate torque were compared to the code and other available expressions. It was found that ACI, CSA, and EC equations can be extrapolated without any modification to predict the torsional strength of HSC box-girders longitudinally reinforced with BFRP bars under combined T-V-M. In addition, a new approach was suggested, which can predict the ultimate torsional twist capacity reasonably well.

The effect of Corroded Longitudinal Steel Bars on Flexural Behavior of Reinforced Concrete Beams

This study aims to examine the relationship between the corrosion rate of longitudinal tensile steel bars and the maximum flexural strength of reinforced concrete RC beams. The study's methodology is designed to show the structural behavior of corroded and non-corroded RC beams, such as ultimate load, deflection, stiffness, crack patterns, and failure mode. Three rectangular beams were cast with dimensions (150× 200 ×1200) mm, and all specimens have the same amount of longitudinal and transverse reinforcement and the same concrete strength. The major parameter is the theoretical mass loss level due to corrosion (0, 10, 15) %. Electrochemical technique was used to accelerate the corrosion in the longitudinal tensile bars. All RC beams were tested under four-point monotonic loading. The test results confirm that the cracking load in corroded beams decreased by 25% comparative to the non- corroded beam. The increase of the percent of corrosion experimental mass loss by 8.25 and 14.15 % decreased the ultimate load by about 14 % and 27%, respectively. This reduction coincided with the decrease in deflection values in mid-span for the ultimate load, which decreased by 53.9% and 46.3%. However, the flexural stiffness was reduced by 13.4 and 15.6% for corroded beams with mass loss (8.25 and 14.15), respectively, compared to the control beam (non-corroded RC beam).

CO2 reduction in tunnelling from the point of view of construction design and implementation

AbstractTunnel construction is not immune to the climate crisis – here too there is an urgent need to improve the carbon footprint. The production of concrete and consumption of cement cause climate‐damaging CO2 emissions. A tunnel with a 10 m diameter, for example, generates around 10 t of CO2 per linear metre. The main priority is thus to reduce the amount of concrete and steel reinforcement used and to select low‐carbon cements and binders, as well as employing single‐shell construction methods suited to the requirements of the construction project. We need to consider practical approaches to reducing concrete volumes which go beyond structural requirements. CO2 reduction in tunnelling starts with the design and approval process, so financial incentives must be built into award criteria and construction contracts. This article aims to highlight ideas which in future will play an increasingly important role in the design of underground construction works than is currently the case. Although many well‐established work practices and design details in underground construction are based on decades of experience and are bound by normative and contractual framework conditions, it is now time to re‐examine the facts and consider new ideas that reflect the need to reduce CO2 in concrete construction.

Flexural–Shear Performance of Lightweight Concrete Panels with High Insulation Capacity

With the increased interest in the inherent fire resistance of organic insulators, various precast concrete insulation panels have been developed. However, precast concrete insulation panels still have structural and fire resistance problems resulting from a low composite action and unclosed cross-sectional details. To improve composite action and fire resistance, this study proposes the closed cross-sectional details of insulator panels with lightweight aggregate concrete, insulation material, and wire mesh. The objective of this study is to examine the flexural–shear performance of precast lightweight concrete panels with closed cross-sectional details developed for exterior cladding with high insulation capacity. Six full-sized insulation panels were tested under two-point top loadings. The main investigated test parameters to vary the moment–shear ratio of the insulation panels were the amount of the shear reinforcement and shear span–effective depth ratio. Test results indicate that the insulation panels with moment–shear ratios of 2.60 or higher were governed by shear, indicating that the longitudinal bars remained in an elastic state until the peak load of the insulation panels was reached. Thus, an increase in the moment–shear ratio of the insulation panels led to more brittle failure characteristics. Meanwhile, the insulation panels governed by flexure exhibited plastic flow performance in the applied load–deflection curve and well-distributed cracks. In particular, the maximal flexural moments of insulation panels with moment–shear ratios of 0.75 or less were higher than those calculated from the equations specified in ACI 318-19, indicating that the composite action was fully exerted. Overall, the developed insulation panels with cross-sectional details must be designed to a have moment–shear ratio of 0.75 or less to fulfil the ductile response under extreme lateral loads and exert full composite action.

Tribological performance of AZ91D/HfCp magnesium composite prepared through stir-ultrasonic-squeeze casting technique

The present work investigates the influence of hafnium carbide, an ultra-high temperature ceramic reinforcement on the dry sliding wear behaviour of AZ91D magnesium composite. AZ91D/5 wt.% hafnium carbide composite and AZ91D alloy were fabricated using stir-ultrasonic treatment-squeeze casting method followed by heat treatment (T6). Microstructure and intermetallic phase studies were performed using scanning electron microscopy and X-ray diffraction techniques. Density, porosity and hardness of the materials were determined. Wear tests at room temperature were conducted at various sliding speeds (0.25–1 m/s) and normal loads (12.5–50 N), using a pin-on-disc tribometer. The temperature of wear varied from 50–200 °C for high-temperature wear tests. Compared to alloy, the composite showed better wear performance under all test conditions. Increasing the normal load increased the wear rate of both materials, but the wear rate decreased with an increase in sliding speed. The friction at the sliding interface decreased with an increase in normal load and sliding speed. The mechanisms of wear for both materials were abrasion, delamination, and oxidation at room temperature. At high temperatures, there was a dramatic increase in the wear rate of the alloy at 150 °C, whereas the wear resistance of composites improved up to 150 °C due to the presence of small amounts of hafnium carbide ultra-high temperature ceramic reinforcement. Abrasion, oxidation, delamination, and plastic yield were the primary wear mechanisms at high temperatures.

A New Approach to the Structure-Properties Relationships Determination for Porous Filled Reinforced Materials.

This study describes a new mathematical approach to the relationship between mechanical properties (tensile modulus, ultimate strength, and strain), composition as well as structure of porous-filled reinforced composites. The composite system consisted of a polyurethane matrix, a rubber filler, and a small amount of polyethylene terephthalate as a reinforcement. The newly proposed equations are based on a special mixing rule with the same basic form for all studied properties. The mixing rule contains a correction parameter η, which differs in different filler content in the filled part of the composite. Here, a cubic exponential function including the product of suitable structural parameters and exponents ensuring the best fitting and describable by matrix properties were successfully defined to fit the different values of correction parameter. The proposed equations should be a suitable step to obtain a relationship for describing the mechanical behavior of porous-filled and reinforced composites in the case of a small amount of reinforcement.

Mechanical properties of rice husk ash, an environmental pollutant, based composites: A step towards sustainable hybrid composites

ABSTRACT There is a dual perspective regarding agricultural materials. The first one is regarding the removal of certain chemical elements for specific applications, and the second one is regarding the recovery of certain elements to make them more appealing. The most appropriate use of agricultural and industrial waste materials demands the development of knowledge insights as a requirement for setting up of demonstration plants on a pilot basis and large-scale industrial adoption resulting in all associated socio-economic benefits. The Stir casting method is employed to fabricate the Metal Matrix Composites (MMCs) material for the application of various industrial products. In the present paper, Aluminum (Al6061) hybrid composite is fabricated and reinforced with Silicon Carbide (SiC), Alumina (Al2O3), Zirconia (ZrSiO4) and agro-waste material, such as Rice Husk Ash (RHA) particles of various configurations. The amount of reinforcement varies SiC (0–2.5 wt%), Al2O3 (0–1.1 wt%), ZrSiO4 (0–0.5 wt%) and RHA (0–1.4 wt%). The effect of reinforcement SiC, Al2O3, ZrSiO4 and RHA on ultimate tensile strength (σut), yield strength (σyt), elongation, breaking strength (σb) and hardness has been studied. Experimental results revealed that hybrid metal matrix composites are improved for σut and σyt by 45.03% and 82.1%. The elongation and hardness of the composite are also enhanced by 19.43% and 12.72% from the base material.

Experimental Study of Hollow RC Beams Strengthened by Steel Fiber under Pure Torsion

This paper examines the effectiveness of pure torsional loads on hollow reinforced concrete high-strengthened beams. Engineers need to know how much twist a structural member generates when exposed to torsional loads to design it properly. This is done through an experimental investigation of the torsional behavior of reinforced concrete (RC) beams using twelve hollow rectangular beams with varying parameters, such as the spacing of the stirrups, the influence of the steel fiber fraction, and the main reinforcement amount. Four values of fiber volume fractions (0, 0.5%, 0.75%, and 1%), three spacings of transverse reinforcements (60,100, and 150 mm), and various longitudinal reinforcements (8Ф12 mm, 6Ф12 mm, and 4Ф12 mm) have been used. The tested beams had the same length (1000 mm), cross-sections, concrete mixture, and quality control. In the hollow beams, the interior dimensions were 180 mm × 180 mm, while the exterior dimensions were 300 mm × 300 mm. Torsional loads were applied to all the beams using custom-built test equipment. This study highlighted that the structural characteristics of hollow RC beams could be improved by increasing the fiber volume, lowering the stirrup spacing, and increasing the longitudinal reinforcement. Torsion moments rose by 132% when the fractional volume of fiber was increased from 0% to 1%, while they rose by 71.27% when the longitudinal reinforcement was increased from 4 to 8 bars for beams with fractional volumes of fiber of 0.5 percent and the same transverse reinforcement ratios.