Strength Of Beams Research Articles

STUDY OF THE EFFICIENCY OF REINFORCED CONCRETE BRIDGES RECONSTRUCTION UNDER THE TYPICAL PROJECT VOL. 56 WITH BEAMS STRENGTHENING BY CHANGING STATIC SCHEME

Purpose. Study of the actual nature of the spatial work and the regularity of the distribution of the temporary load between the beams of the existing simply supported cross-ribbed span structure and under various options for changing its static schemes, involving in joint work the reinforced concrete overlay slab and other new elements of the reconstruction. Methodology. In order to evaluate the effectiveness of the structural solutions used during the reconstruction of the expansion and strengthening of the span structure, it is planned to conduct a set of alternate tests with sequential introduction into its composition before each alternate test of one of the new structural elements of the reconstruction, involved in joint work with the existing beams. That is, for each successive test, the impact of only one factor was assessed, the inclusion of which in the composition of the existing span structure changed its operating conditions. The effectiveness of its application was evaluated by direct comparison of the deflections of the beams of the next tests with the deflections of the previous ones. Results of five (1… 5) span structure tests were carried out during successive stages of reconstruction, i.e. in the following sequence: 1 – test of the span structure in the existing state according to the simply supported static scheme; 2 – after installation of the horizontal immobility of the supporting parts; 3 – after complete pinching of the beams on the supports; 4 – after installation of the overhead plate of the expansion of the span structure on pinched beams; 5 – after completion of reconstruction before handover. The results of these tests were beam deflections and transverse distribution coefficients determined from them. The effect of joint work of new reconstruction elements with the existing beams was established by comparing the deflections of these beams from tests 1-4 under the same load schemes. We obtained the ratio f1:f2:f3=1:1.46:2.95, from which it is evident that the greatest effect of strengthening the beams is achieved in the static scheme pinched on the supports. The experimental transverse distribution coefficients turned out to be almost the same for all investigated static schemes, which indicates that the possibility of their spatial calculation using one method. The scientific novelty consists in the experimental and theoretical substantiation of the effectiveness and operational reliability and strengthening of beams of reinforced concrete span structures by changing the static scheme. Practical significance – wide application of the method of strengthening reinforced concrete span structures by changing the static scheme in the practice of their reconstruction.

Flexural Behaviour of FRC Beams Wrapped With FRP

Structural elements such as beams, slabs and columns may require strengthening during their service life period. A concrete structure may need strengthening for many reasons such as to increase live load capacity, to add reinforcement to a member that has been unsigned or wrongly constructed. The FRPs have various advantages like, high strength to weight ratio, corrosion resistance and ease of installation and flexibility in its use. FRP material which are available in the form of sheet are being used to strengthen a variety of RC elements to enhance the flexural, shear and axial load carrying capacity of these elements. The objective of this experiment is to strengthen the RC beams using fibres and FRP sheets in flexure. In this experimental program CFRP and GFRP sheets were applied to the bottom surface and sides of the concrete beam with different configuration and their performance in flexure were studied. In this experimental program eight RC beams of size 1500 x 150 x 200mm were casted with two 10mm dia. bars as tension zone, two 8mm dia. bars as compression zone and 8mm dia. bars @ 200mm c/c spacing as shear reinforcement. The experimental result shows that the flexural strength of FRP wrapped beams were increased in the range of 23.49% to 67.9% in comparison with the flexural strength of the control beam (unwrapped). The flexural strength of the beam wrapped with the single layer CFRP at the soffit and around the sides (for full depth of the beam) and beam wrapped with the single layer GFRP at the soffit and around the sides (for full depth of the beam) exhibits better performance compared with other FRP beams and increase in flexure was 67.9% in comparison with the capacity of the control beam.

Rehabilitation of RC Structure by Using Ferrocement Jacketing

Many structures fail or deteriorate before completion of its intended life span due to poor quality of material used, lack of mix design, poor workmanship, attacked by environmental agencies, etc. Sometimes due to slenderness of column or less reinforcement provided than actual requirements, less depth/thickness provided in flexural members, etc. feels excessive vibration during walking on floor ultimately develops cracks. Strength of such structural elements can be found by using non-destructive tests like Rebound hammer test, ultrasonic pulse velocity test, etc. If strength of existing structural elements is less than desired strength then structural consultant suggested strengthening of structural elements. There are various methods used in strengthening of existing structural elements like pressure grouting, fibre wrapping, chemical treatment, structural steel support, jacketing, etc. But these techniques are very costly and need precise quality control activity. In the present of investigation, strengthening of beam and column elements of a building by ferrocement techniques and steel jacketing were carried out and cost and cost comparison and strength results before and after strengthening are presented. It is observed that the strength og structural by ferrocement technique is cost effective than steel jacketing technique. And also has increase in the strength of RCC elements

BEARING CAPACITY OF A BEAM DAMAGED DURING COMBAT ACTIONS STRENGTHENED WITH THE USE OF FIBER CONCRETE

The paper presents the results of a study of the load-bearing capacity of a beam damaged during hostilities, which was reinforced with steel-reinforced concrete. A beam with 20 percent damage in the compression zone is considered. Before concreting, a foam insert was installed in the area of the planned damage, the shape and dimensions of which corresponded to the planned damage. After the concrete was set to 70% grade strength, the liner was pulled out, and the resulting cavity was filled with a 2% mixture of fiber concrete. This is one of the beam strengthening options in a comprehensive damaged beam testing program, which involves the study of a series of beams with different types of damage, varying damage zone (tensile and compression) and its magnitude, geometry and method of strengthening. The authors developed a special stand for testing. The load-bearing capacity of the damaged beam reinforced with fiber concrete was 80.6 kN, or 89.5% of the load-bearing capacity of the intact beam. Cracking started at the 4th load stage, when the load value was 16.1 kN, or 20% of the bearing capacity of the damaged beam. At the same time, 10 cracks formed in the zone of pure bending, the opening width of which did not exceed half the price of the microscope division, which is 0.005 mm. At the next eight stages of loading (up to 48.4kN), no new cracks were observed, and the width of the opening of all the ones that had previously formed doubled - it reached 0.01mm. At the 12th, 13th and 19th stages of loading, 4 more cracks appeared. The maximum final crack opening width was 1.2 mm. Up to a load of 68.5kN, which is 85% of the load-bearing capacity of the damaged beam, the reinforced concrete liner works with the beam almost as a unit, and then the compressed zone of concrete squeezes out the liner. It is claimed that the strengthening of a beam with 20% damage in the compressed zone in the manner considered in the work allows to achieve its bearing capacity, which is almost 90% of the bearing capacity of an undamaged beam.

Numerical Approach for Residual Strengths of Fiber-Reinforced Concrete Beams with Different Densities

A numerical approach is proposed to predict the flexural stress–crack mouth opening displacement (CMOD) relationship of fiber-reinforced concrete (FRC) beams. The compressive strength and density of concrete as well as various fiber parameters are considered in the compressive and tensile stress–strain relationships of concrete employed in the analysis. The nonlinear hinge model for fictitious crack propagation generalized by Olesen is also utilized to calculate the CMOD from the curvature determined from critical beam sections. The theoretical flexural stress–CMOD curves corresponded well with the measured curves. They indicated that the mean and standard deviation of normalized root mean square error values determined from 136 FRC beams were 0.237 and 0.118, respectively. A comprehensive parametric study is then conducted by numerically analyzing the primary variables influencing the CMOD response of FRC beams at extensive ranges. This enables the formulation of simple closed-form equations to determine the residual flexural strengths straightforwardly. The residual flexural strengths yielded by the derived equations agree better with the test results than with those given by previous empirical equations, yielding fewer scatters in the ratios between the experimental results and predictions is observed. Consequently, the present equations have potential in reliably assessing the residual flexural strengths of FRC with a wide range of variables, such as compressive strength, density, aggregate size, and fiber parameters.

Synergistic effects of web reinforcement and hybrid fibres on shear performance of continuous deep beams with unsymmetrical web openings

Application of fibre-reinforced concrete or novel web reinforcement detailing could be an effective way to enhance structural behaviour of continuous deep beams with web openings. However, there are very few experimental works studying the synergistic effects of these two methods. Therefore, an experimental programme is introduced in this paper to study synergistic effects of shear reinforcement and hybrid fibres on shear strength of nine double-span deep beams with unsymmetrical web openings (denoted as pierced span). The test specimens were designed to consist of a pierced beam span with a web opening and an adjacent solid beam span. The spans with openings were designed with different shear reinforcement configurations. It was experimentally shown that provision of sufficient web steels above and below web openings has the most important and beneficial effect on ultimate shear strength of the pierced spans. Besides, a tailored steel reinforcing method was also proposed that is capable of improving strut capacity near the web opening. In addition, adoption of hybrid fibre reinforcement led to enhanced crack-opening resistance, ultimate shear strength and shear deformation. Based on the research outcomes, it was recommended to adopt the proposed detailing method or fibre reinforcement dosage for shear strength enhancement of continuous deep beams with web openings. Furthermore, an analytical model was adopted to the shear strength of continuous deep beams accounting for web openings, steel stirrups, and hybrid fibres, which yielded safe predictions.

Advancing Shear Capacity Estimation in Rectangular RC Beams: A Cutting-Edge Artificial Intelligence Approach for Assessing the Contribution of FRP

Shear strength prediction in FRP-bonded reinforced concrete beams is crucial for ensuring structural integrity and safety. In this extensive investigation, advanced machine learning algorithms are harnessed to achieve precise shear strength predictions for rectangular RC beams reinforced with FRP sheets. The aim of this research is to enhance the accuracy and reliability of shear strength estimation, providing valuable insights for the design and assessment of FRP-strengthened structures. The primary contributions of this study lie in the meticulous comparison of various machine learning algorithms, including Xgboost, Gradient Boosting, Random Forest, AdaBoost, K-nearest neighbors, and ElasticNet. Through comprehensive evaluation based on predictive performance, the most suitable model for accurately estimating the shear strength of FRP-reinforced rectangular RC beams is identified. Notably, Xgboost emerges as the superior performer, boasting an impressive R2 value of 0.901. It outperforms other algorithms and demonstrates the lowest RMSE, MAE, and MAPE values, establishing itself as the most accurate and reliable predictor. Furthermore, a sensitivity analysis is conducted using artificial neural networks to assess the influence of input variables. This additional research facet sheds light on the critical factors shaping shear strength outcomes. The study, as a whole, represents a substantial contribution to advancing the development of accurate and dependable prediction models. The practical implications of this work are far-reaching, particularly for engineering applications in the realm of structures reinforced with FRP. The findings have the potential to transform the approach to the design and assessment of such structures, elevating safety, efficiency, and performance to new heights.

Flexural strength of concrete beams strengthened with BFRP and GFRP using cement and epoxy adhesives subjected to elevated temperatures

Flexural strength of concrete beams strengthened with BFRP and GFRP using cement and epoxy adhesives subjected to elevated temperatures

Interfacial reinforcement of carbon fiber composites through a chlorinated aramid nanofiber interphase

Carbon fiber-reinforced polymers (CFRPs) rely on a strong interfacial bond between the reinforcing fibers and polymeric matrix to yield the high strength and toughness expected by a composite material. Poor interfacial strength leads to sub-optimal load transfer and introduces stress concentrations, which can reduce overall performance and result in catastrophic failure. Aramid nanofibers (ANFs) have shown significant promise for interfacial reinforcement in polymeric composite systems due to their high tensile strength, large specific surface area, and abundant polar functional groups. However, due to the chemically inert nature of carbon fibers, ANFs do not readily bond to their surface – thus limiting their application to CFRPs. In this work, we demonstrate that chlorination of ANFs and oxygen plasma treatment of carbon fibers enables the formation of a chlorinated ANF (Cl-ANF) interphase through chemical and physical adsorption using a simple dip-coating process, while fully preserving the tensile strength of the carbon fibers. The Cl-ANF interphase yielded a 79.8 % increase in interfacial shear strength and a 33.7 % increase in short beam strength. By enhancing the interfacial bond between fiber and matrix without degradation of the fiber's tensile strength, this method provides a rapid and reliable process to improve the mechanical properties of CFRP composites.

Cold-formed stainless steel beams with single web hole at elevated temperatures

Steel structures are often used in buildings due to their advantage in weight-to-strength ratio. However, their structural capacity deteriorates in fire as the temperature of the structures rises. Investigation of cold-formed stainless steel (CFSS) structures at elevated temperatures is still limited, especially for rectangular hollow section (RHS) beams having a single web hole in the mid-span (perforated web). Therefore, a numerical investigation was conducted to evaluate the current design provisions to calculate the strength of such beams at elevated temperatures ranging from 22 - 900 °C. A total of 400 specimens of stainless steel grades austenitic (EN 1.4301) and lean duplex (EN 1.4162) were considered. The investigation used finite element analysis (FEA) to simulate the behaviour of RHS beams with perforated web under pure bending. The finite element (FE) model was validated against a series of experimental results available in literature. The comparison between flexural strengths obtained from FEA with design values calculated from the current design rules showed that the design rules are conservative. However, they are not always reliable and safe for RHS beams without and with a perforated web for the two material grades at elevated temperatures. In this study, only the design rules specified by Eurocode 3 are shown to be reliable and safe.

Numerical Analysis of an Innovative Double-Strap Joint for the Splicing of Near-Surface Mounted Fiber-Reinforced Polymer Bars for Reinforced Concrete Beam Strengthening

The issue of the cut-off splicing of an additional fiber-reinforced polymer (FRP) bar in the near-surface mounted (NSM) technique for reinforced concrete (RC) beam strengthening exposed dominantly to bending is insufficiently investigated. A possible solution of this issue is a new proposed technique: a double-strap joint. It implies the widening of the groove at the cut-off location and the symmetrical installing of additional supplements of FRP reinforcement. In this research, beam strength has been determined for the following cases: additional NSM FRP reinforcement without a cut-off, with a cut-off, and without overlapping, and with different lengths of splice overlapping. A nonlinear analysis based on the finite element method (FEM) has been applied. The length of the cut-off splice of the additional FRP reinforcement with glass fibers (GFRP) was 20Ø, 40Ø, and 60Ø. The validation of the numerical model and a comparison of the results were conducted by using the authors’ experiments. It has been shown that, in the case of a cut-off of NSM GFRP bars, a significant loss in strengthening efficiency occurs, and that, with an increase in the overlapping length, this loss decreases. An overlapping length of 60Ø provides full strengthening. An efficiency assessment was carried out via the use of a parametric study, varying the FRP bar material type and its diameter for a constant splicing length.

Data-driven prediction of the shear capacity of ETS-FRP-strengthened beams in the hybrid 2PKT–ML approach

A new approach that combines analytical two-parameter kinematic theory (2PKT) with machine learning (ML) models for estimating the shear capacity of embedded through-section (ETS)-strengthened reinforced concrete (RC) beams is proposed. The 2PKT was first developed to validate its representativeness and confidence against the available experimental data of ETS-retrofitted RC beams. Given the deficiency of the test data, the developed 2PKT was utilized to generate a large data pool with 2643 samples. The aim was to optimize the ML algorithms, namely, the random forest, extreme gradient boosting (XGBoost), light gradient boosting machine, and artificial neural network (ANN) algorithm. The optimized ANN model exhibited the highest accuracy in predicting the total shear strength of ETS-strengthened beams and ETS shear contribution. In terms of predicting the total shear strength of ETS-strengthened beams, the ANN model achieved R2 values of 0.99, 0.98, and 0.96 for the training, validation, and testing data, respectively. By contrast, the ANN model could predict ETS shear contribution with high accuracy, with R2 values of 0.99, 0.99, and 0.97 for the training, validation, and testing data, respectively. Then, the effects of all design variables on the shear capacity of the ETS-strengthened beams were investigated using the hybrid 2PKT–ML. The obtained trends could well appraise the reasonability of the proposed approach.

Mechanical Properties and Flexural Response of Palm Shell Aggregate Lightweight Reinforced Concrete Beam

This work focuses on examining the mechanical characteristics and flexural response of reinforced concrete (RC) beams by incorporating oil palm shell (OPS) lightweight aggregate from oil palm shell waste. The OPS aggregates are replaced in various percentages, such as 0 to 50% of natural coarse aggregate (NCA). Mechanical properties of OPS concrete were conducted, and these properties were used to quantify the flexural performance of RC beams. Five RC beams with several gradations of OPS aggregates were cast and tested for this investigation. The first cracking, ultimate strength, load-deflection behavior, ductility index, and failure patterns of OPS aggregate beams were investigated as the corresponding behaviors to the NCA concrete beam. The fresh properties analysis demonstrated lessening the slump test by varied concentrations of OPS concrete. Furthermore, compressive strength was reduced by 44.73%, 50.83%, 53.33%, and 57.22% compared to 10%, 15%, 20%, and 50% OPC substitution at 28 days. Increasing OPS content in concrete mixes decreased splitting tensile strength, comparable to the compressive strength test. Modulus of rupture and modulus of elasticity experiments exhibited a similar trend toward reduction over the whole range of OPS concentrations (0–50%) in concrete. It was revealed that the flexural capacity of beams tends to decrease the strength with the increased proportion of OPS aggregate. Moreover, crack patterns and failure modes of beams are also emphasized in this paper for the variation of OPS replacement in the NCA. The OPS aggregate RC beam’s test results have great potential to be implemented in low-cost civil infrastructures.

Flexural strength of ultra-high performance concrete beams with stainless steel wire mesh: experimental and finite element analysis

The addition of a stainless steel wire mesh (SSWM) at the bottom of ultra-high performance concrete (UHPC) was proposed for improving the flexural strength of UHPC and solving the problem of low initial cracking performance. A method combining experiments and numerical simulations was used to study the ability of the SSWM to enhance the flexural strength of UHPC and evaluate its cracking resistance. The wire diameter, mesh size, number of steel wire mesh layers, and length of the SSWM were the geometric parameters considered in the experiments. The experimental results showed that the flexural strength of UHPC is improved by SSWM, and the load–deflection curve, ductility, strain distribution, and failure mode of UHPC were assessed. The flexural strength and failure modes of UHPC were evaluated accurately using a numerical model. The wire diameter, mesh size, number of steel wire mesh layers, and wire mesh length parameters were analyzed using the model. The relationship between the flexural strength and the geometric parameters was obtained through an in-depth study of the parameter analysis results using multiple linear regression.

Elastic local buckling coefficients of I-shaped beams considering flange–web interaction

Since using high–strength and high–performance steels has become a more common structural design practice in building and bridge construction, there is an increased potential for designing extremely thin-walled I-shaped beam members to enhance the efficiency of the steel beam design. For a more accurate design approach for these thin-walled I-beam members, particularly when they are near noncompact limits, it is necessary to explore more rational methods for determining the elastic local buckling strength of I-beams. This study aimed to investigate the local buckling behavior and strength of I-shape structural sections by considering flange-web interactions through three-dimensional finite element analysis. The goal was to provide a more reasonable estimation of local buckling strength under uniform bending. To evaluate the local buckling behavior of flange and web panels and explain it reasonably, this study adopted the ratio of flange-web slenderness (λf/λw) and height-to-width ratio (H/bf) of I-shaped beams which can affect buckling mode shapes and local buckling strength of I-shaped beams induced by flange local and web bend bucklings. Finally, this study presented design equations for both flange local and web-bend buckling coefficients considering λf/λw and H/bf. It was expected that the presented local buckling coefficients (kf) for flanges and webs could lead to a more reasonable design, as compared to the existing AISC design provisions.

The performance of Strengthened Lightweight RC Beams with different Techniques upon Exposure to Fire

Introduction: Reinforced concrete beams are used in a wide range of applications. In addition, reducing the weight of the concrete used increases the advantages of the beams. The main objective of this work is to study the performance of structurally strengthened lightweight reinforced concrete beams with different techniques with or without exposure to fire under concentric load and the efficacy of the fire protection system. Methods: The experimental specimens included eight half-scale tested rectangle beams with typical dimensions of 300 mm depth, 1700 mm total length, 150 mm total width, 50 mm cover, and 1500 mm span. The density of the lightweight polystyrene foam concrete was 1820kg/m3. The main parameters were fire resistance, different types of strengthening material for lightweight concrete beams, shape of the ferrocement layer on the lightweight concrete surface, and ferrocement thickness. Results: The results were analyzed in terms of crack patterns, failure modes, load deflection, load-strain behavior, stiffness, ductility, deformability, and absorbed energy. Conclusion: From the analysis of the results, the strength of LWC beams increased the strength and stiffness of the tested beam, and the fire protection system was found effective in protecting CFRP limitation from deterioration. In a theoretical study, the conservatism degree for calculating the maximum allowable flexure force was evaluated according to the ECP203, ACI-318, and BS-8110 codes.

Numerical Analysis of Concrete Deep Beams Reinforced with Glass Fiber-Reinforced Polymer Bars

This research aimed to generate data through a verified numerical model. The data were subsequently used to introduce a simplified analytical expression for the prediction of the shear strength of concrete deep beams reinforced with glass fiber-reinforced polymer (GFRP) reinforcing bars. A three-dimensional (3D) numerical simulation model for a large-scale GFRP-reinforced concrete deep beam (300 × 1200 × 5000 mm) was developed and validated against published experimental data. A parametric study was then conducted to examine the effects of key variables on the behavior and shear strength of GFRP-reinforced concrete deep beams. Eighteen 3D numerical models were developed to study the interaction between the concrete compressive strength (f’c), the shear span-to-depth ratio (a/h), the spacing between web reinforcement (s), and the shear strength. The a/h value was either 1.0 or 1.5. The values of f’c were 28, 37, and 50 MPa. The spacings between the web reinforcement, if present, were 100 and 200 mm. The results of the parametric study indicated that the shear strength of deep beam models increased almost linearly with an increase in f’c and a decrease in the stirrup spacing irrespective of the value of a/h. The strength reduction caused by increasing a/h was more pronounced for the beam models with the lower f’c and greater stirrup spacing. The simplified analytical expression introduced in the present study provided a reasonable prediction for the shear strength of GFRP-reinforced concrete deep beams.

Shear span behavior of reinforced concrete beams with circular and rectangular openings

In reinforced concrete (RC) beams, opening is frequently required for the passage of utility ducts and/or pipes. The presence of such web openings leads to a reduction of the strength and sitffeness of the beam. This paper aims to contribute to better understanding the shear behavior of RC beam with web opening in the shear span. The study is based on an experimental program carried out on three RC beams. All beam specimens were 850 mm long with a cross section of 150 × 250 mm and a shear span to beam depth ratio (a/d) of 1.48. One beam without any openings served as the control specimen, while the remaining two beams featured circular or rectangular openings within the shear span. The test results obtained from this experimental program offer insights into the shear behavior of beams with openings. Furthermore, a simplified calculation was conducted to determine the shear strength of the test specimens, considering the influence of openings. This calculation provided a deeper understanding of how openings contribute to the reduction in the shear strength of RC beams.

Torsion Improvement of Reinforced Self-Compacting Concrete Beams Using Epoxy Injection and CFRP

Few researchers have investigated the internal torsional reinforcement of box timbers, so little research has been conducted on this particular fortification method. The primary objective is to find out the possibility of adding a certain percentage of RCA to the NC mixtures, as well as verifying the success achieved in repairing the cracks that occurred as a result of torsion with CFRP or injecting with epoxy, which has not been addressed in previous research and literature reviews. This study reinforces reinforced SCC box columns subjected to complete torsion with CFRP sheets and epoxy resin injections. Four reinforced SCC specimens (the first beam with 0%, the second beam with 33.3%, the third beam with 67.7%, and the fourth beam with 100% RCA by weight) were subjected to pure torsion until failure. The dimensions and reinforcement of every specimen are identical. In addition, the applied torque-twist angle relationship at the midspan and end span was investigated. Bending experiments were performed to establish load-deflection curves and assess failure modes. After structural rehabilitation, all beams exhibited increased rigidity values, according to the results. Epoxy resin and CFRP sheet contributed to the specimens' increased ultimate load. The ultimate strength of RCA beams strengthened with CFRP and injected with epoxy increased. The specimens' flexural strength was considerably enhanced by the combination of surface roughness and fracture injection, and the effectiveness of using RCA was very good; it could be replaced with NCA in concrete mixtures, according to the ratio and need. Doi: 10.28991/CEJ-2023-09-11-05 Full Text: PDF

Experimental and Computational Research on the Shear Performance of Partially Filled Narrow-Width Steel Box-UHPC-Combined Girders under Negative Moment Action

To examine the vertical shear behavior of narrow-width steel box-UHPC (Ultra-High Performance Concrete) composite beams with partial filling under negative bending moments, a total of six test beams were created and constructed in this study. The variables considered during the design and fabrication process included the flange thickness of UHPC, the amount of steel fibers in UHPC, and the height of the concrete filling. Reverse static concentration loading was applied to the beams. Compared to the C40 concrete flange, the cracking load of the 1/2 plate thickness UHPC flange and pure UHPC flange increased by 55.6% and 66.7%, respectively. The yield load witnessed a rise of 17.3% and 22.7%, while the ultimate load experienced an increase of 7% and 13.1%. This suggests that incorporating steel fibers can regulate the formation of cracks, enhance the flexibility of the flanges, and improve the overall shear capacity of the composite beams. When steel fibers were used in the amount of 2% of the concrete volume, the cracking resistance of the flange plate was increased by 16.7%. Partially filled and fully filled composite beams exhibited a 7.7% and 30.8% augmentation in cracking load, a 35.3% and 49.9% increase in yield load, and a 41% and 83.2% elevation in ultimate load when contrasted with composite beams devoid of concrete infusion within the steel box. The above observation implies that the incorporation of concrete within the steel box significantly improves the yield strength and ultimate shear capacity of the composite beams. The shear strength of the narrow-width steel box-UHPC composite beams, which are partially filled, shows a significant relationship with the experimental results when applying the principle of component superposition.