H-shaped Steel Research Articles

Experimental and numerical investigation on seismic performance of S-RC-SRC composite joint

The seismic performance of H-shaped steel upper column-RC beam-SRC lower column joint (S-RC-SRC composite joint) was investigated experimentally and numerically. The axial compression ratio n and size of H-shaped steel was studied in the test. The low-frequency cyclic loading tests were performed on four S-RC-SRC composite joints. The test results showed that the concrete in the connection zone was severely damaged. On basis of strain analysis and experimental observations, the flexural failure mode at the oblique section in connection zone was proposed. The relatively plump but pinched hysteretic curves indicated that S-RC-SRC composite joint possessed considerable energy dissipation capacity, with peak h eq of 0.192–0.208 and asymmetrical ductility coefficient ( μ + ‾ = 7.08 and μ − ‾ = 3.03). The strength and stiffness degradation were significant and asymmetrical in different loading directions. Experimentally-validated finite element method was applied to simulate the S-RC-SRC composite joint via ABAQUS. The parameter study showed that: the impact of axial compression ratio should be considered in two stages (low and high), under the low axial compression (0.2–0.35) hardly affected the hysteretic behavior but high axial compression (0.6–0.8) would cause distinguished failure mode; the enlargement of steel size could reduce the ultimate bearing capacity slightly. A theoretical method for evaluating the flexural bearing capacity S-RC-SRC composite joint was proposed and proved to be applicable with the maximum deviation of 3.5%. • A new type of connection joint named by S-RC-SRC composite joint was investigated experimentally and numerically. • The flexural failure at the oblique section in connection zone was observed and the seismic performance was discussed. • Finite element model for S-RC-SRC composite joint was established and validated. • Numerically parametric analysis focusing on f c , n and size of steel section was carried out. • The method of evaluating the flexural bearing capacity of S-RC-SRC composite joint was proposed and validated.

Experimental and numerical investigation on seismic performance of retrofitted RC columns with web direct/indirect bonding external H-section

This paper presents experimental and numerical investigations of existing reinforced concrete (RC) columns enhanced by two seismic retrofit methods, web indirect bonding and web direct bonding combined with a steel endplate. The former retrofit system is an H-shaped steel member connected to an existing RC column with anchor bolts and an infilled-concrete layer. The latter is quite similar to the web indirect bonding method but incorporates a steel endplate and a stud bolt layer additionally. Three RC columns with/without the retrofitted methods, designated BC, SC-T2, and SC-T4, were built and tested under cyclic loading. The experimental findings showed that the retrofitted RC columns were superior to the non-retrofitted specimen in terms of initial stiffness, peak strength, and energy dissipation capacity. Based on the experimental responses, finite element (FE) models were developed and verified with the experimental results. The results obtained from the simulations were consistent with those from the experiments, indicating the finite element (FE) models can reproduce the seismic responses of bare and retrofitted RC columns with slight simulation variation. Finally, a parametric analysis was carried out to investigate the effect of the material strength and length of the added components on the seismic behavior of the SC-T2 specimen.

The bond behavior of steel reinforced recycled concrete under cyclic reversed load

In order to investigate the cyclic bond behavior between H-shaped steel and recycled concrete, thirteen cyclic reversed push-out tests and one monotonic push-out test were carried out. The main parameters of the tests were recycled concrete aggregate (RCA) replacement percentage, thickness of concrete cover, stirrup ratio, recycled concrete strength and loading scheme. The experimental results indicate that the pinch effect on the hysteresis curves of load-slip is remarkable. The envelope curves can be divided into four stages: minimal slip stage, slip development stage, falling stage and residual stage. The bond stress of steel reinforced recycled concrete (SRRC) under cyclic reversed load declines by 40%∼50% comparing to SRRC under monotonic push-out load. Slip appears on both ends of the specimens firstly under cyclic reversed load. The influence of the main factors on the cyclic bond stress is analyzed. The energy dissipation mainly occurs in the falling stage and residual stage.

The Plastic Damage Distribution of Beam-column Joint Consisting of H-shaped Steel

To investigate the influence of panel zone section size on the plastic damage distribution of H-shaped beam–column joints, a cruciform beam–column joint composed of common beams, columns and panel zone was considered as the analytical model, in which the area ratio of flange-to-web and the section type of H-shaped steel column were considered as main parameters. Based on the force and moment balance at the centre of the panel zone, the rules of plastic damage of the beam–column joint were studied and the results were as follows: the H-shaped steel columns with wide flange, the formation of plastic hinge in the panel zone was prior to that of the column; the same result was obtained with middle or narrow flange H-shaped steel column, with the exception that the axial compression ratio of the column was equal to 0.6 and the height–width ratio of panel zone was equal to 2; when the axial compression ratio of column was less than or equal to 0.4 and the H-shaped steel column strength was 1–5 times of the panel zone strength, it may result in the difficulty in the construction of ‘strong panel zone’ structural treatment.

Mechanical behavior of T-shaped CFST column to steel beam joint

The seismic performance of T-shaped CFST column to H-shaped steel beam joint with vertical rib stiffeners was investigated experimentally and numerically in this study. Specifically, the joint shear deformation, inter-story drift ratio, joint stiffness, and energy dissipation capacity were analyzed. The test results demonstrate that the joint with vertical stiffeners has good seismic behavior and meets the requirements of Eurocode 3 for rigid joints in a braced frame. A finite element model for the multi-cell T-shaped CFST column to H-shaped steel beam joint with vertical rib stiffeners was established to investigate the influences of the following parameters on joint strength and joint stiffness: the width-to-thickness ratio of steel tube, vertical rib dimensions, and the axial load ratio of column. The numerical results indicate that the width-to-thickness ratio of steel tube and vertical rib dimensions play an important role in improving the joint strength and stiffness. A mechanical model for the joint strength was also developed, in which the contributions from the front face and side faces of steel tube and the vertical rib stiffeners were considered. To facilitate the practical design, a simplified design method for joint strength as well as the design suggestions for detailing are proposed based on the mechanical model.

Shear capacity of H-shaped steel beam with randomly located pitting corrosion

The H-shaped steel beam is one of the most commonly adopted steel members in building structures and industrial structures, including, bridges, ocean platforms, and industrial equipment. For the steel beams adopted in such structures, corrosion is inevitable, of which pitting corrosion is one of the most common types. The shear capacity of the webs of steel beam is an important performance factor utilized by steel structures. This study aims to reveal the influence of pitting corrosion on the shear capacity of corroded H-shaped steel beams. The relationship between shear capacity and mass loss ratio is the key research content. This study investigates the constant and randomly corroded depths. An analytical method for predicting the residual shear capacity of corroded steel beam is proposed. Results indicate that the proposed method has high accuracy in predicting the shear capacity of H-shaped steel beam with corroded web. The proposed analytical method is applicable for constant and random tw,c/ tw. The conclusions derived in this work are suitable for steel webs with normalized slenderness λs of less than 1 and can be applied to steel beams with different material strengths.

Finite Element Simulation of the Cooling Process of H-shaped Steel after Circular Nozzle Impinging

ANSYS fluent, a finite element numerical simulation software, was used to establish a three-dimensional model of the H-shaped steel web under the impinging impact of nozzle jet. A numerical stimulation analysis was conducted on the mode of water flow and the heat transfer of the H-shaped steel web. In the model, the finite volume method was used to discretize the model into a tetrahedral unstructured grid, the multi-flow VOF model and the achievable K-e model were used to solve the Reynolds average N-S equation, and the numerical solution method adopted the PISO algorithm. This paper aims to calculate the heat transfer performance of the ultra-fast cooling process of the H-shaped steel web under different boundary conditions, as well as explore the influence of impinging time on the distribution of water volume and temperature fields of the web by simulating the cooling process of H-shaped steel web with circular nozzle jet.

Experimental Study on the Bending Behavior of Steel-Wood Composite Beams

This paper proposes a steel-wood composite beam with H-shaped steel beam webs glued to the wood. As a new type of composite beam, it combines the advantages of low energy consumption of wood, high permeability, and less pollution and the advantages of light weight and high strength of steel, high degree of assembly, short construction period, and less construction waste generated. Carrying out research is of great significance to improve the mechanical properties of steel-wood composite beams and promote the development of steel-wood composite structures. In this paper, three hot-rolled H-beam-larch composite beams and one pure steel beam were tested for bending capacity. The composite beams are divided into two different combinations of A and B types. The two sides of the web are connected with larch wood by structural glue to form a composite beam. The type B composite beam is a larch wood glued on both sides of the H-shaped steel web and penetrates the bolts at the same time. Through the three-point monotonic static grading loading of the composite beam, the deflection change, failure phenomenon, and form of the specimen during the experiment were observed. Under the circumstances, the ultimate bearing capacity of the test piece was changed to study the combined effect of larch and hot-rolled H-shaped steel. The results show that the overall performance of the H-shaped steel-larch composite beam is good. Bonding wooden boards on both sides of the steel beam web can improve the bearing capacity, and the form of the member is more reasonable and effective; increasing the cross-sectional size of the H-beam in the steel-wood composite beam can further improve the bearing capacity of the composite beam; adding bolt anchorage on the basis of the structural glue used in the composite beam can further improve the bearing capacity of the composite beam. The superposition principle is used to simplify the calculation of the ultimate bearing capacity of H-shaped steel-larch composite beams. Comparing the calculation results with the test results, the data are in good agreement, which can provide a design reference for the practical application of such composite beams.

Restoring force model for modular prefabricated steel-reinforced concrete column to H-shaped steel beam composite joints

Restoring force model is one of the most critical indices reflecting the seismic performance of building structures or components. This paper investigates a restoring force model for steel H-shaped beam to modular prefabricated steel-reinforced concrete column composite joint (hereinafter MPSC joint). Compared with the previous experimental research results, a trilinear skeleton curve model for MPSC joint was proposed through numerical regression analysis. The proposed model was calibrated by comparing the finite element models. The ratios of calculational results to FEM results were 0.94–1.22 on the yield, peak, and failure points. Moreover, the coefficients of variation were 0.07, 0.03, and 0.08 under the three status. The proposed model showed high accuracy and be applied to the design of MPSC joints.

Structural Design and Analysis of Zhaogangwang Steel E-commerce Technology Center

This project is a complex over-limit multi-storey structure. The structural over-limit items were analyzed, key parts were adopted to improve the seismic grade, the frame column was made of reinforced concrete column, and the thickness of the floor slab and the reinforcement were designed. The conversion truss was located on the 4th floor, with a span of 25.2m, and adopted H-shaped steel member steel truss. The performance-based design of the structure only meets the requirements of the supporting column conversion truss and related vertical members, and meets the non-yielding of large earthquakes.

RESEARCH ON THE INFLUENCE OF GUSSET PLATE CONNECTIONS ON THE OUT-OF-PLANE STABILITY OF THE H-SHAPED STEEL BRACE

Experiments on 12 specimens of H-shaped steel bracing members with gusset plate connections (brace system) are conducted to study the effect of gusset plate on the out-of-plane rotational restraint and stability capacity of the brace. The experiments are under cyclic loading with constant-amplitude axial displacement, and the effect of clearance distance on the stability capacity of the brace is obtained. For the cyclic constant-amplitude loading condition, the degradation criterion of stability capacity of the brace system is obtained and the calculation formula of the post-buckling capacity is suggested. The finite element method is used to simulate the behaviors of specimens, and the simulated results are in good agreement with the experimental results. Moreover, a large-scale parameter analysis of the full-sized brace system is carried out. The results indicate that the brace slenderness ratio, the thickness of the gusset plate, the clearance distance and the brace angle have significant impacts on the out-of-plane rotational stiffness and stability capacity of the brace system. Based on the influence of these critical parameters on the rotational restraint of gusset plate and considering the size effect, the formulas for calculating the rotational stiffness of the gusset plate connection and the effective length factor of the brace are proposed, which can be used to easily obtain the stability capacity of the brace system.

Cyclic loading test of abnormal joints in SRC frame-bentmain building structure

Due to functional requirements, SRC column-RC beam abnormal joints with characteristics of strong beam weak column, variable column section, unequal beam height and staggered height exist in the Steel reinforced concrete (SRC) frame-bent main building structure of thermal power plant (TPP). This paper presents the experimental results of these abnormal joints through cyclic loading tests on five specimens with scaling factor of 1/5. The staggered height and whether adding H-shaped steel in beam or not were changing parameters of specimens. The failure patterns, bearing capacity, energy dissipation and ductile performance were analyzed. In addition, the stress mechanism of the abnormal joint was discussed based on the diagonal strut model. The research results showed that the abnormal exterior joints occurred shear failure and column end hinge flexural failure; reducing beam height through adding H-shaped steel in the beam of abnormal exterior joint could improve the crack resistance and ductility; the abnormal interior joints with different staggered heights occurred column ends flexural failure; the joint with larger staggered height had the higher bearing capacity and stiffness, but lower ductility. The concrete compression strut mechanism is still applicable to the abnormal joints in TPP, but it is affected by the abnormal characteristics.

Seismic behavior of plane frame with special-shaped CFST columns, H-shaped steel beams and vertical rib connections

The seismic behavior of special-shaped concrete-filled steel tubular (CFST) column to H-shaped steel beam plane frame (SCFSTF) with vertical rib connections was investigated experimentally and numerically in this study. Double-bay two-story SCFSTFs with the scale ratio of 1/2 were tested under constant vertical compressive load and cyclic horizontal loads (or displacements), which is a pseudo static experiment considering the axial load ratio. Based on the experimental results, failure modes, bearing capacity, hysteretic curve, skeleton curve, energy dissipation, ductility, rigidity degradation and strength degradation of SCFSTFs were investigated. As a result, a typical strong column-weak beam failure mode was determined. The degradation in strength and rigidity were minimal and energy dissipation capacity and ductility of frames were adequate, demonstrating excellent seismic performance. Besides, energy dissipation capacity and horizontal resistance were improved with axial load ratio increasing within the parametric range of this test. After the test, a finite element method based on software ABAQUS was carried out to further investigate the seismic performance. The numerical results of skeleton curve, rigidity, yield load, peak load and stress distribution agreed well with the test results. The plastic hinge formation process and ultimate failure mode were further investigated using the finite element model.

Bending Behavior of Corroded H-Shaped Steel Beam in Underground Environment

To investigate the residual bending strength of a corroded H-shaped steel beam in an underground coal mining environment, the law governing the degradation of the mechanical properties of corroded steel was first investigated through tensile testing. Subsequently, a four-point bending test was conducted on corroded H-shaped steel beams. The influence of the corrosion rate and sustained loading ratio on the residual bending performance of a corroded H-beam was investigated. The results reveal that the uniform corrosion and uneven corrosion of the steel occurred simultaneously. Additionally, pits with a small size appeared on the steel surface and the number of these pits increased with the corrosion time. Four different fracture modes were observed after the tensile test, and the yield strength and ultimate strength of the corroded steel decreased as the corrosion rate increased. In the bending test, the failure mode of the corroded H-shaped steel beam was not changed by the corrosion. The bearing capacity, stiffness, and ductility of the corroded H-shaped steel beams decreased with the increase in the corrosion rate, and the sustained loading further decreased the bearing capacity. Finally, a simple method for assessing the yield load and ultimate load of corroded H-shaped steel beams is proposed.

Interfacial bond–slip behavior between H-shaped steel and engineered cementitious composites (ECCs)

To study the interfacial bond–slip behavior of shaped steel–engineered cementitious composite (ECC) materials, nine full-scale H-shaped steel–ECC specimens were tested. Theoretical equations for the ultimate and residual bond stresses were established via statistical fitting. A tensile constitutive model of the ECC was proposed, and cohesive elements were used in a finite element (FE) analysis to simulate the shaped steel–ECC interface. The results show that the failure mode of the tested specimens is a splitting failure with multiple typical splitting and intumescent cracks in the ECC material. The bond stress has a non-uniform distribution, and the outer flange of the H-shaped steel bears most of the load. Compared with the test and FE results, Eqs. (6) and (11) exhibit good computational accuracy. The rationality of the FE modeling strategy, especially the manner of addressing the issues of tensile constitutive model of ECC and contact of shaped steel and ECC, is verified.

Seismic performance of steel columns corroded in general atmosphere

Steel structures exposed to general atmosphere for a long time are highly susceptible to corrosion damage, which would lead to the degradation of service performance of the components and even structures. This article focuses on the effect of corrosion on the seismic performance of steel column. The accelerated corrosion tests in general atmosphere were conducted on 7 H-shaped steel columns and 20 steel plates. Then the obtained plate specimens were subjected to monotonic tensile tests and cyclic loading tests, and the steel columns were subjected to pseudo-static tests, respectively, to study the effects of corrosion on their mechanical properties and seismic performance. Then, a simplified three-dimensional finite element model (FEM) capable of accurately simulating the hysteretic response of corroded steel columns under low-cycle loading was established. Experimental results indicated that the yield strength, tensile strength, elastic modulus and peak strain of corroded steel plate decreased linearly with the proposed corrosion damage parameter Dn, and the energy dissipations under low-cycle loading were significantly reduced. There is a correlation between the cyclic hardening parameters of corroded steel and the yield-tensile strength difference (SD), and then a simplified formula was proposed. Corrosion could result in the premature entrance of each loading stage of corroded columns and the deterioration of buckling deformation range, bearing capacity and energy dissipation, etc. In addition, a larger axial compression ratio (CR) would further accelerate the failure process of corroded columns. The parametric finite element analysis (FEA) indicated that greater damage was found for steel columns with non-uniform corrosion, and hysteretic performance degraded more significantly when corrosion distributed at flanges or foot zone.

Bond-slip behaviour of H-shaped steel embedded in UHPFRC

The present study experimentally and analytically investigated the push-out behaviour of H-shaped steel section embedded in ultrahigh-performance fibre-reinforced concrete (UHPFRC). The effect of significant parameters such as the concrete types, fibre content, embedded steel length, transverse reinforcement ratio and concrete cover on the bond stress, development of bond stress along the embedded length and failure mechanism has been reported. The test results show that the bond slip behaviour of steel-UHPFRC is different from the bond slip behaviour of steel-normal concrete and steel-high strength concrete. The bond-slip curves of steel-normal concrete and steel-high strength concrete exhibit brittle behaviour, and the bond strength decreases rapidly after reaching the peak load, with a residual bond strength of approximately one-half of the peak bond strength. The bond-slip curves of steel-UHPFRC show an obvious ductility, which exhibits a unique displacement pseudoplastic effect. The residual bond strength can still reach from 80% to 90% of the peak bond strength. Compared to steel-normal concrete, the transverse confinement of stirrups has a limited effect on the bond strength in the steel-UHPFRC substrate, but a higher stirrup ratio can improve cracking resistance. The experimental campaign quantifies the local bond stress development and finds that the strain distribution in steel follows an exponential rule along the steel embedded length. Based on the theory of mean bond and local bond stress, the present study proposes empirical approaches to predict the ultimate and residual bond resistance with satisfactory precision. The research findings serve to explain the interface bond mechanism between UHPFRC and steel, which is significant for the design of steel-UHPFRC composite structures and verify the feasibility of eliminating longitudinal rebars and stirrups by using UHPFRC in composite columns.

Design and Mechanical Performance Analysis of a New Type of Column-Column-Beam Prefabricated Steel Frame Joint

Joints are the key factors that determine the construction difficulty and structural safety of prefabricated steel structures. However, the existing prefabricated joints of square steel tube and H-shaped steel beam frame have few reference forms, and there are still a series of problems in practical engineering applications, such as construction difficulties and poor applicability. Therefore, a new type of column-column-beam joint with variable beam height and its construction scheme are designed in this paper. The joint is bolted rather than welded in the process of field prefabricated. It can solve the problem of vertical and horizontal connection of steel frame structure through one joint at the same time, thus effectively saving construction cost and ensuring construction quality. In addition, the detailed modeling and comprehensive mechanical properties analysis of the joint scheme are carried out in this paper. The ultimate bearing capacity, stiffness characteristics, failure modes and hysteretic behavior of joint schemes under low cyclic loading are also evaluated.

Experimental and numerical investigation on the seismic behavior of plane frames with special-shaped concrete-filled steel tubular columns

The seismic behavior of (plane) frames with special-shaped concrete-filled steel tubular (CFST) columns (SCFSTFs), H-shaped steel beams, and exterior diaphragm connections was investigated experimentally and numerically in this study. Double-bay two-story SCFSTFs with a scale ratio of 1/2 were tested under constant vertical compressive load and cyclic horizontal loads (or displacements), which is a pseudo-static experiment considering the axial compression ratio. Based on the experimental results, failure modes, bearing capacity, hysteretic curves, skeleton curves, energy dissipation, ductility, rigidity degradation, and strength degradation of SCFSTFs were investigated. As a result, a typical strong column-weak beam failure mode was observed; degradation in strength and rigidity were minimal, and the energy dissipation capacity and ductility of SCFSTFs were adequate, demonstrating excellent seismic performance. Besides, energy dissipation capacity and horizontal load bearing capacity were improved with increasing axial compression ratios within the parametric range of this test. After testing, a finite element method based on ABAQUS was carried out to further investigate the seismic performance of SCFSTFs. The numerical results of skeleton curves, stiffness, yield load, ultimate load, and stress distribution agreed well with the test results. The plastic hinge formation process and failure mode were also further investigated using the finite element method.

Experimental and numerical studies of a new prefabricated steel frame joint without field-welding: Design and static performance

In this study, we explored the connection between the square steel tubular column and H-shaped steel beam in a high-rise prefabricated steel frame structure, where a new type of connection method was designed and researched. Based on the full-scale static experiments, the ultimate failure mechanism of the designed joint was analyzed for two configurations. The moment–rotation (M–R) curves and mechanical properties of both configurations were acquired and compared with that of a traditional welded joint having the same scale. The results showed that the failure modes of our proposed joint appeared as the failure of some sensitive regions that located in the connecting areas, accompanied by the out-of-plane buckling of the beam. Moreover, the rotational stiffness of our proposed joint was relatively lower than that of the traditional welded joint, but their differences in the flexural capacity were not obvious. The capacity of joint with the stiffening rib (JD-1) was slightly higher than that of the one without the stiffening rib (JD-2). Finally, a refined finite element modelling (FEM) was established and verified by result comparisons. Based on this, a further check of joint design was accordingly achieved by evaluating its integral stress development and concentration. The results illustrated that the connector stiffening can affect the stress distributions among all assembled components. In contrast, JD-2 showed a better performance in the uniformity of stress distribution by appropriately reducing the connecting stiffening.