High-strength Steel Bars Research Articles

Experimental research on seismic behaviors of RC columns considering buckling of HRB600 longitudinal steel bars

The inelastic buckling of longitudinal bars and premature fracture that followed can always be observed in laboratory research and earthquake damage of reinforced concrete (RC) columns. The buckling deformation and accompanied fracture of HRB600 high-strength steel bars are more significant than those of conventional reinforcing bars, but the buckling properties of HRB600 reinforcement and the influence of premature fracture on the seismic performance of RC columns are far from clear. In this paper, low cyclic loading tests were conducted on six full-scale RC columns reinforced with HRB600 reinforcement by changing the slenderness ratios of longitudinal bars and the axial compression ratios of columns, and the lateral buckling displacements of longitudinal bars were measured by an identified method. Based on the lateral buckling displacements, the buckling behaviors of longitudinal bars were analyzed. It shows that cover concrete has a significant constraint effect on preventing buckling of HRB600 reinforcement. The inelastic buckling behaviors and premature fracture of HRB600 bars on the ultimate deformation capacity and ductility of RC columns were investigated according to the lateral buckling displacements and ductility coefficient. It is found that the increase of the slenderness ratio would cause larger buckling displacements making the local plastic deformation concentration and low-cycle fatigue damage of HRB600 reinforcement more serious, resulting in the premature fracture of longitudinal bars and decrease of ductility of RC columns. Furthermore, a series of individual bars accompanied by the RC columns were tested. Based on the average stress–strain curves, the effects of yield strength and slenderness ratio were discussed. Former researches of conventional longitudinal bars were involved to form a comparison group with HRB600 bars. The results indicate that the deformation capacity reserves of HRB600 reinforcement after 85% peak load were significantly lower compared with conventional bars. It is suggested to limit the application of RC columns reinforced with HRB600 longitudinal bars in high seismic intensity areas and improve the limitation on the slenderness ratio of high-strength steel bars.

Damage-free self-centring links for eccentrically braced frames: development and numerical study

Many recent research studies focused on the development of innovative seismic-resilient structures, chasing the objectives of minimising both seismic damage and repair time, hence allowing the definition of structures able to go back to the undamaged, fully functional condition in a short time. Steel seismic-resilient structures have been widely investigated in the past few years while considering solutions based on moment-resisting and concentrically braced frames. While the first category may be characterised by low stiffness, the second category is often characterised by low ductility. Conversely, eccentrically braced frames (EBFs) represent a compromise between the two and allow both strength and stiffness to be optimised while providing ‘good’ ductility capacity. The present study investigates a solution for damage-free self-centring EBFs relying on damage-free self-centring devices as seismic links (SC-links). The SC-links are based on post-tensioned high-strength steel bars with disk springs to provide the self-centring behaviour, and friction dampers to dissipate the seismic energy. Analytical equations governing the global behaviour of the connection are developed. A four-storey EBF complying with Eurocode 8 provisions is designed with conventional seismic links and upgraded with the proposed SC-link. The third storey of the structure is extracted to develop refined 3-D finite element (FE) models in ABAQUS. The results of the FE simulations are used to investigate the local behaviour of the seismic device and validate the accuracy of the analytical predictions. Moreover, a simplified 2-D FE model is developed in OpenSees to carry out Incremental Dynamic Analysis providing information on the global response of the structure. Residual and peak interstorey drifts and link rotations are monitored as Engineering Demand Parameters, and the seismic performances of the frames are compared.

A comparative study on the seismic performance of RC beam-column joints retrofitted by ECC, FRP, and concrete jacketing methods

Reinforced concrete (RC) beam-column joints in many old buildings do not have appropriate seismic detailing that allows them to provide sufficient strength and stiffness in strong seismic events. To improve the seismic performance of these deficient beam-column joints, this study proposes a new retrofitting method based on high-strength steel bar mesh and Engineering Cementitious Composite (ECC), a fiber-reinforced cementitious material that shows high tensile ductility and damage tolerance. The proposed method reduces the required size of the retrofitting jacket through the combined use of ECC jackets and high-strength steel bar mesh. The performance of the proposed ECC jacketing method was compared with that of concrete jackets and fiber-reinforced-polymer (FRP) jackets. Experimental program included cyclic testing of four exterior beam-column joints, i.e., one control specimen and three others retrofitted using ECC, concrete, and FRP jacketing. Results showed that (1) reinforced ECC jackets confined the joint core and prevented localized damage in the joint zone via formation of dense and fine cracks, (2) the beam-column joint retrofitted using ECC jackets with high-strength steel mesh exhibited the favorable beam flexural failure, while the other three joints showed joint shear failure, (3) compared to other two retrofitting methods, the reinforced ECC jacket more effectively increased the strength, stiffness retention, energy dissipation capacity, deformation capacity, and collapse drift. In addition to experimental study, suitable strength models were suggested to evaluate the strength and failure patterns of the retrofitted exterior beam-column joints.

Seismic performance of prefabricated square hollow section piers strengthened by jacketing using UHPC and high-strength steel

Pier damages have become a primary contributing factor to bridge seismic damage, because they may cause serious loss of integrity and even the collapse of the whole bridge structure. Therefore, developing and improving methods for the seismic strengthening of existing bridge piers can play a significant role in preventing bridge failures. In this study, ultra-high-performance concrete (UHPC) and HTRB600E high-strength steel bars were used to strengthen prefabricated square hollow section piers that had undergone severe flexural damage due to seismic demands. By conducting quasi-static tests on the prefabricated piers before and after strengthening, seismic performance indices, such as the hysteresis curve, skeleton curve, energy dissipation, stiffness degradation, residual displacement, and curvature, were compared and analysed. Under cyclic loading, the deformation of the strengthened pier shaft section was small, and no evident plastic failure was observed. The unreinforced pier shaft exhibited a clear bending shear failure mode, with a plastic hinge first developing at the top of the strengthened shaft section. Based on the quasi-static test results, a refined finite element model of the pier was implemented and verified. By varying the thickness and height of the UHPC reinforcing layer and the strength of the steel bars, their influence on the seismic capacity of the pier was explored. The experimental results indicate that the jacketing using UHPC and high-strength steel bars significantly improved the flexural capacity, energy dissipation, and initial stiffness of the retrofitted specimens and effectively restored and enhanced their seismic performance.

Synergistic tensile response of reinforced ultra high performance concrete with low fiber contents

From the perspectives of ductility, economic and construction, reinforced ultra high performance concrete (UHPC) structures with low fiber contents have a significant potential in applications. This paper studied the tensile behaviors and damage mechanisms of reinforced UHPC with low fiber contents based on the direct tensile tests accompanied with acoustic emission (AE) detection system. The test results show that the high strength steel bar can prolong the tensile multiple-cracking stage of reinforced UHPC with low fiber contents in some extent at the serviceability stage and further improve its tensile ductility via inducing additional longitudinal cracks at the failure stage. It is found that the low fiber contents and steel bar grades have marginal effect on the tension stiffening at the first cracking of reinforced UHPC. Non-negligible tension stiffening effect still remains at yielding of steel bar and it is more obvious for normal strength steel bar and UHPC with a higher fiber content. The AE weighted peak frequency can identify the tensile damage model of reinforced UHPC with low fiber contents: no internal damage occurs during stage Ⅰ; matrix cracking occurs accompanied by marginal fiber pull-out during stage Ⅱ; matrix cracking and fiber pull-out are dominated during stage III and stage IV, respectively.

Investigation on low-cycle fatigue performance of high-strength steel bars including the effect of inelastic buckling

Bar buckling and subsequently low-cycle fatigue fracture is one of the main failure modes of RC columns/piers under strong earthquakes. Due to the adoption of new metallurgical technology and possibly enduring higher stress, high-strength steel bars (HSSB) may be more prone to occur buckling and low-cycle fatigue failure, which will detrimentally affect the seismic performance of RC columns/piers. In view of this, this paper studies the buckling and low-cycle fatigue performance of high-strength steel bars (HSSB) HTRB600 and compares with normal steel bars (NSB) HRB400E. At first, the monotonic tensile and compressive tests of HTRB600 and HRB400E steel bars with different slenderness ratios (L/D = 6, 8, 10, 12, 15) were conducted to study their monotonic tensile and compressive properties. Then, the low-cycle fatigue tests of HTRB600 and HRB400E reinforcing steel with different strain amplitudes and slenderness ratios were conducted to evaluate their low-cycle fatigue performance. The fatigue life prediction formulas for HTRB600 and HRB400E steel bars taking into account the effects of inelastic buckling were proposed through the regression analysis of test results. Moreover, the fractured surfaces obtained by the scanning electron microscope (SEM) were used to compare the low-cycle fatigue failure features of HTRB600 and HRB400E steel bars. Finally, a finite element model (FEM) was developed to simulate the nonlinear mechanical behaviors of HTRB600 and HRB400E steel bars under monotonic and cyclic loading. Test results show that HTRB600 steel bars present lower tensile ductility, more severe post-buckling softening and pinching effect than HRB400E steel bars. The increase in yield strength, buckling length and strain amplitude will reduce the low-cycle fatigue life of steel bars. The range of striation marks observed from low-cycle fatigue fractured surfaces by SEM for HTRB600 steel bar is smaller than HRB400E steel. The calibrated buckling and low-cycle fatigue parameters by the validated finite element model (FEM) can be adopted to accurately simulate the inelastic seismic response of RC structures.

Dynamic response of GFRP-reinforced UHPC beams under close-in blast loading

Combined use of ultrahigh-performance concrete (UHPC) with glass fiber reinforced polymer (GFRP) reinforcement has the potential for further blast resistance enhancement of reinforced concrete (RC), due to the improved toughness of UHPC and the high strength-to-weight ratio of GFRP. This paper aims to fill the gap on the effectiveness of GFRP bars on the blast response of UHPC beams. The blast resistance of UHPC beams built with GFRP bars (UHPC-GFRP beams) is experimentally and numerically investigated in this paper. In the experimental scheme, twelve beams strengthened with various types of concrete and reinforcement are tested under near-field explosions. The properties of UHPC beams reinforced with GFRP bars are compared with specimens reinforced with normal-strength steel (NSS) and high-strength steel (HSS) bars. GFRP bars reduce the maximum displacements, which enhances the blast performance of UHPC beams. However, reinforcing UHPC beams with GFRP bars results in large rebound displacements. In addition, the coupled finite element model is adopted to predict the response of test beams. The numerical method using LS-DYNA achieves reasonable accuracy. Moreover, the damage process, energy characteristics, reaction forces, stress response and the effect of the compressive reinforcement are examined to better depict the damage mechanism of the UHPC-GFRP beams.

Experimental Evaluation of Effect Factors on Seismic Performance of Concrete Columns Reinforced with HTRB630 High-Strength Steel Bars

HTRB630 steel bar is a new type of high-strength steel bars. To study the seismic performance and promote the application of concrete columns reinforced with HTRB630 high-strength steel bars, the pseudo-static test of 10 concrete columns reinforced with HTRB630 high-strength steel bars and 3 concrete columns reinforced with HRB400 was carried out. Test specimens were divided into five categories according to concrete grade, reinforcement strength, and degree of confinement. The effect of concrete strength (C45 and C60), axial load ratio (0.1 and 0.25), equal strength substitution of longitudinal reinforcements (HTRB630 and HRB400), equal strength and volume substitution of stirrups (HTRB630 and HRB400), equal strength substitution of confined reinforcements (HTRB630 and HRB400) on the seismic performance are analyzed and discussed from the failure mode, hysteresis loops, skeleton curves, lateral strength, ductility, energy dissipation capacity, stiffness and strength degradation. The failure mode of each specimen was bending failure. Reducing of the axial lo ratio or increasing the strength of reinforcements, the seismic performance of the specimen could be improved. C60 concrete can improve the seismic performance of HTRB630 reinforced columns. The lateral strength of the concrete column specimen with HTRB630 reinforcements was slightly increased, and the ductility and energy dissipation capacity were reduced, the stiffness degradation was more gradual, the strength degradation coefficient was greater than 0.94, but still met the requirements of the code for seismic design of buildings (GB50011-2010).

Development of High-Strength and Atmospheric Corrosion Resistant Steel Bars with Low Cost

Development of High-Strength and Atmospheric Corrosion Resistant Steel Bars with Low Cost

Experimental Study and Calculation Methods of Shear Capacity for High-Strength Reinforced Concrete Full-Scale Deep Beams.

The shear behavior of 8 high-strength concrete full-scale deep beams with high-strength steel bars was studied. The depth beam size was 100 mm × 900 mm × 2200 mm, the test parameters included the shear span-to-depth ratio ( = 0.9, 0.6, 0.3), longitudinal reinforcement ratio (.66%, 1.06%, 1.26%) and stirrup reinforcement ratio ( = 0, 0.26%, 0.34%, 0.5%). The ratio of the cracking load of the inclined section to the ultimate load is between 30% and 50%, and the bending deformation of the deep beam is small, showing the characteristics of brittle failure for deep beams. Under the action of a concentrated load, the failure mode of deep beams with a small shear span ratio is the failure of the diagonal compression struts, which is very different from that of shallow beams with a large shear span ratio. With the increase of shear span ratio from 0.3 to 0.9, the ultimate shear capacity of deep beams decreases by 19.33%. With the increase of longitudinal reinforcement ratio from 0.67% to 1.27%, the ultimate shear capacity of deep beams increased by 45.02%. With the increase of vertical stirrup reinforcement ratio from 0% to 0.5%, the ultimate shear capacity of deep beams increased by 8.93%. Increasing the area of longitudinal bars or stirrups limited the transverse tensile strain of the compression struts, which is conducive to improving the compressive strength of the compression struts of deep beams and then improving the bearing capacity of deep beams. The strut-and-tie model (STM) is more suitable for analyzing the shear capacity of deep beams. The calculation methods for calculating the shear capacity of deep beams were compared with ACI 318-19, CSA A23 3-19, EN 1992-1-1:2004, Tan–Tan model, Tan–Cheng model, softened STM (SSTM) and simplified SSTM (SSSTM). The results showed that the shear capacity of deep beams could be well predicted by reasonably determining the STM parameters.

Investigation on drift ratio limits of PVA fiber reinforced concrete columns under different performance levels based on the Kunnath damage model

Within the context of the performance-based seismic design (PBSD), it is crucial to determine the drift ratio limits of PVA-FRCs under different performance levels. In this article, seven PVA fibers and high strength steel bars reinforced concrete columns were designed, and the quasi-static test was carried out to investigate their failure models and hysteretic loops. The calculated damage indexes using the Kunnath damage model were compared with the measured damage index ranges. The results indicated that the Kunnath damage model could accurately calculate the damage indexes of PVA-FRCs. According to the failure process of columns, the cracking point, yield point, peak point and ultimate point were used as the performance level control points of PVA-FRCs. Based on the idea of PBSD, the seismic performance levels of PVA-FRCs were divided into normal operation performance level, temporary operation performance level, reparable operation performance level, life safety performance level and collapse prevention performance level. Combined with the fiber concrete column test data in the references, the relative frequency statistics of the drift ratios of 38 PVA-FRCs at each feature point were carried out. The drift ratio limits under different performance levels and the corresponding damage indexes for PVA fiber reinforced concrete columns were established. Through the statistical analysis of relative frequency, the drift ratio limits of PVA-FRCs under different performance levels with more than 85% safety assurance rate were obtained, which were 1/300, 1/150, 1/80, 1/55 and 1/40, respectively. The performance level, damage state, lateral drift ratio limit and damage index were combined to form a relatively complete system to provide a reference for the anti-seismic repair of PVA fiber reinforced concrete structures.

Experimental research on fatigue behavior of prestressed ultra-high performance concrete beams with high-strength steel bars

Ultra-High Performance Concrete (UHPC) is a new type of cement-based composite material that exhibits exceptional compressive strength, tensile properties and durability compared to ordinary concrete. Comprehensive research on the flexural fatigue behavior of prestressed UHPC beams is presented in this paper. The failure mode of the fatigue beam is the fatigue fracture of the tensile steel bar in the pure bending section. In the fatigue process, the fatigue behaviors of prestressed UHPC beams including crack width, midspan deflection, the strain of UHPC in compression zone and strain of high-strength steel bars exhibit two stages which are corresponding to damage initiation, steady damage propagation. The residual deflection at the midspan increases with the increase of fatigue cycles. The prestressed UHPC beam reinforced with high-strength steel bars shows stable structural behavior even after concrete cracking. The S–N expression of prestressed UHPC beam with consideration of the influence of stress amplitude of high-strength steel bars is proposed. The stiffness degradation formula of the fatigue beam and calculation methods of fatigue crack width and fatigue deflection are proposed.

Experimental and numerical investigations on seismic performance of HTRB630 high-strength steel bars reinforced concrete columns

Heat-treated ribbed bar 630 (HTRB630) is a new type of the main 630 MPa reinforcing steel produced in China. To explore the possibility of using HTRB630 high-strength steel bars to replace HRB400 steel bars in reinforced concrete structures, experimental and numerical investigations on seismic performance of HTRB630 high-strength steel bars and HRB400 steel bars reinforced concrete columns are presented in this article. Firstly, the pseudo-static experiment of HTRB630 and HRB400 steel bars reinforced concrete columns is carried out. Secondly, an efficient modeling method is proposed to simulate and analyze the seismic performance of reinforced concrete columns on OpenSees platform based on the measured mechanical properties. ConcreteCM model and Reinforcing Steel model are applied to accurately simulate the uniaxial constitutive relationship of concrete and steel bars respectively. The constitutive parameters of confined concrete of specimens are calculated using the iterative algorithm method to effectively consider the degree of improvement of concrete performance in the core area by transverse steel reinforcements. Considering the bond-slip effect and shear deformation of reinforcements, a rotation spring element and a shear spring element are introduced on the fiber model. Finally, the applicability and accuracy of the numerical simulation results are verified by the experiment results on the hysteresis curves, normalized skeleton curves, bearing capacity, displacement ductility, energy dissipation capacity and degradation of stiffness. The experimental results indicate that the failure modes of the reinforced concrete column specimens are all bending failure. Hysteresis loops of the specimens reinforced HTRB630 and HRB400 steel bars are all bow-shaped. After the equal strength of HTRB630 steel bars, the shape of the hysteresis curve is not changed significantly. HTRB630 high-strength steel bars reinforced concrete columns can achieve good seismic performance under the premise of reasonable reinforcements. The numerical results indicate that the finite element model has a good simulation effect on most seismic performance indicators. For specimens with relatively low axial pressure and insignificant pinching, the error of the simulated hysteresis curve is larger; for specimens with relatively high axial pressure and obvious pinching, the error of the simulated hysteresis curve is smaller. The simulation errors of those seismic performance indicators are about 10%.

Research on critical anchorage length of UHPC-CA and HTRB600E high-strength steel bars

The bond performance between ultra-high performance concrete with coarse aggregate (UHPC-CA) and HTRB600E high strength steel bar was studied. The pullout test studied the influence of anchorage length on bond strength, and the effect of protective layer thickness on anchorage length was explored based on test and theoretical analysis. The results show that the relationship between bond strength and anchorage length satisfies the inverse proportional function. The protective layer thickness and anchorage length of specimens meet the quantitative relationship of the inverse proportional function. According to the results, the commonly used calculation equation of anchorage length of steel bars in building structures is determined.

PHC 파일용 PC 강봉의 열처리에 따른 미세구조 및 기계적 특성

For prestressing concrete (PC) steel bar, high-strength steel bar with spiral groove is used by deform drawing and heat treatment of medium carbon steel, 30MnSi. Since the ø8.8 ㎜ PC steel bar has to be subjected to a different tempering temperature from the existing ø9.2 ㎜ PC bar, the microstructure after tempering through the induction heat treatment method was comparatively analyzed and the tensile stress-strain curves for each heat treatment condition were investigated. The experiment was conducted by controlling the heat treatment temperature by adjusting the current input value. The change of the linear speed compared to the current value has a great influence on the mechanical properties of the product, and the tempered martensite structure is observed in the specimen to which the current value of 98 A and the line speed of 48 m/min is applied, and the tensile strength is 1,455 N/㎟ satisfied.

Cyclic test and numerical analysis of the seismic performance of concrete columns reinforced by HRB600 steel bars

As a new type of high-strength steel bar, hot-rolled ribbed bar (HRB) 600 reinforcement has an obvious yield platform and high elongation. To better understand the seismic performance of HRB600 steel bar reinforced concrete columns, cyclic tests are first conducted to examine the effect of the reinforcement strength, stirrup spacing, and axial compression ratio on their seismic performance. Then, finite element (FE) models of the column specimens are established by OpenSees, and the accuracy is verified by comparison with the experimental results. Finally, parametric analysis is conducted to investigate the effects of the concrete strength, longitudinal reinforcement strength, volume-stirrup ratio, and stirrup strength on the seismic performance of concrete columns. The research results show that the column specimens reinforced by HRB600 reinforcement can achieve an excellent drift ratio capacity of 4.2% when the axial load ratio is 0.5, and have a deformation capacity similar to that of normal-strength bar reinforced concrete columns. The established FE model can simulate well the behavior of HRB600 bar reinforced concrete columns under cyclic loading. The parametric analysis shows that when adopting equal strength replacement of longitudinal reinforcement, the columns built by high- and normal-strength reinforcement have similar strength and deformation capacity, but the high-strength bar reinforced columns have a slightly smaller energy dissipation.

Experimental evaluation of post-tensioned bridge bent under cyclic loads and comparison to hybrid bridge bents

Experimental results for a re-centering bridge bent whose concrete columns were post-tensioned with unbonded high-strength steel bars are presented. The initial post-tensioning forces to achieve column re-centering were obtained using rigid body analogy. Steel collars were provided at the top and bottom ends of the columns for confinement. The column-to-footing interface contained a polyurethane layer inside the shear key to reduce column damage. For the initial post-tensioning forces implemented in the experiment, concrete damage was observed at the bottom of the columns. The post-tensioned (PT) bars remained elastic up to the design drift ratio of 2.0% and yielded at a 5.0% drift ratio; the column longitudinal mild steel bars yielded at a drift ratio of 6.0%. The performance of the post-tensioned bridge bent without any external energy dissipators (PT-Only bent) was compared with that of two similar hybrid bridge bents reinforced with external energy dissipators: the first incorporating tension-only stretch length anchors, and the second incorporating a buckling restrained brace. The two hybrid bents displayed excellent performance compared to the PT-Only bent in terms of strength, stiffness, and hysteretic energy dissipation; however, the PT-Only bent had a superior re-centering efficiency compared to the two hybrid bents.

Bond behaviour of high-strength steel bars in concrete with steel fibres

Reductions in materials consumption through the use of high-strength materials is important in building construction. However, high-strength steel applications have possible challenges such as their effects on bond behaviour and structural ductility. The bond behaviour, total energy capacity and failure modes of headed and straight high-strength and normal-strength steel bars were investigated using pull-out tests. In the experimental programme, 48 concrete specimens with a compressive strength of 40 MPa, different ratios of steel fibres and embedded steel bars with different yield strengths were subject to pull-out tests. The results showed that the headed bars had far greater bond stress and total energy capacity than the straight bars. It was also found that the higher the yield strength of the bars, the higher the energy capacity and bond stress. Although increases in fibre ratios led to increases in energy capacity, they did not absolutely increase the bond stress. The specimens with both headed and straight bars failed by splitting.

Stress corrosion assisted collapse in flat tensile specimens of high-strength structural steel

High-strength steel bars used in construction provide versatile solutions for meeting the modern criteria of sustainability and resilience required in structural engineering, through a sensitivity to assisted cracking places structural integrity at risk and limits the potential applications. One of the bar types commercially available, though less used due to this risk, are made of martensitic steel but recent improvements incorporated to their fabrication led to a randomly oriented lath-martensite microstructure that reduces their brittleness. The objective of the present research was to determine the effect of this martensitic microstructure on bar behavior regarding stress corrosion cracking. In this view, various slow-rate tensile tests have been carried out in an environment that favors hydrogen-assisted cracking and allows subcritical cracking micro-mechanisms to be identified and correlated to the fracture behavior of the bars.

Seismic performance of HSS reinforced interior beam-column joints with high-strength steel fiber concrete and enhanced reinforcements

Reinforced concrete moment frame structures in high seismicity regions were often faced with complicated reinforcement details in the joint resulting in construction difficulty. High-strength steel (HSS) bars were used as longitudinal reinforcements in beams and columns to reduce the bar amount and alleviate steel congestion. High-strength steel fiber concrete (HSSFC) was adopted in the joint to enhance the bonding performance of HSS bars. Meanwhile, an enhanced detail of X-shaped reinforcement was proposed to enhance the shear strength. This study investigated the effect of adopting a hybrid method, including HSSFC and X-shaped enhanced reinforcement, on the seismic behavior of interior beam-column joints (BCJs) with HSS bars. Eight full-scale HSS-reinforced interior BCJs were tested under reversed cyclic loading to examine the seismic performance and evaluate the influences of enhanced reinforcement, shear compression ratio, and HSSFC usage. Seismic performance was evaluated in terms of cracking patterns, loading capacity, energy dissipation, and ductility. Test results showed that HSS-reinforced interior beam-column joints with HSSFC exhibited excellent seismic performance with less concrete damage, enhanced ductility, and increased energy dissipation capacity. Similar results were achieved for HSS-reinforced BCJs with X-shaped enhanced reinforcements. Moreover, slippage of beam longitudinal reinforcements and shear deformation were also decreased due to improved bond performance between HSS bars and HSSFC, resulting in less occurrence of bond-slip at the beam end. A suggested equation was proposed for regulating the diameter of high-strength beam bars through the joint section and the height of the column section.