Research

Open AccessArticle

Numerical Investigation of the Behavior of Unstiffened Semi-Rigid Top and Seat Angle Connections under Monotonic Loading

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Zeynep Fırat Alemdar

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Yusuf Balaban

Buildings 2023, 13(10), 2425; https://doi.org/10.3390/buildings13102425 - 23 Sep 2023

Viewed by 190

Abstract

In steel structures, unstiffened top and seat angle connections (TSACs) show semi-rigid behavior and transfer both the vertical reaction and some end moment of the beam while also making some degree of rotation. The moment–rotation behavior of TSACs has been evaluated using experimental [...] Read more.

In steel structures, unstiffened top and seat angle connections (TSACs) show semi-rigid behavior and transfer both the vertical reaction and some end moment of the beam while also making some degree of rotation. The moment–rotation behavior of TSACs has been evaluated using experimental and numerical analyses under monotonic loading and generally compared in the linear elastic region. In this paper, three-dimensional (3-D) finite element models of the TSACs were developed based on experimental data available from the literature to accurately obtain the moment–rotation results along the curve. The numerical models were verified with the moment–rotation curves of TSACs and the deformed shapes of the angles in the connections. The experimental results show that the finite element model in this study is adequate to predict the moment–rotation behavior of TSACs. The effects of bolt material properties, bolt diameter, bolt pretension load, friction coefficient, and gage distance on the moment–rotation behavior of the connections were investigated using the verified numerical model. The parametric analyses show that almost the same moment–rotation behavior is obtained for the connections by increasing the bolt strength and pretension load and varying the friction coefficients. The ultimate moment capacity of the connections was increased with a decrease in the gage distance. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Analytical Solution for Longitudinal Anti-Push Stiffness of the Middle Tower of Cross-Cable Multi-Tower Cable-Stayed Bridge

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Buildings 2023, 13(9), 2158; https://doi.org/10.3390/buildings13092158 - 25 Aug 2023

Viewed by 207

Abstract

The Queensferry Crossing in Scotland is the first multi-tower cable-stayed bridge with crossed cables in the world. This means that the conceptual design of a cross-cable multi-tower cable-stayed bridge has become a reality. In this paper, the cross-cable action mechanism is studied deeply. [...] Read more.

The Queensferry Crossing in Scotland is the first multi-tower cable-stayed bridge with crossed cables in the world. This means that the conceptual design of a cross-cable multi-tower cable-stayed bridge has become a reality. In this paper, the cross-cable action mechanism is studied deeply. Suppose that the small displacement amount at the top of the side tower is ignored. The deformation coordination principle is used twice to analyze the relationship between the horizontal external force and the top displacement amount of the middle tower. Thus, derive the formula for estimating the anti-push stiffness of cross cables to the middle tower of the multi-tower cable-stayed bridge under the influence of the stiffness of the tower and beam. A numerical example is given to verify this. The research results show that the error between the analytical solution and the finite element solution is less than 8%, which meets the conceptual design requirements of cross-cable multi-tower cable-stayed bridges. The cross cables can reduce the deflection of the main beam and improve the stiffness of the bridge. After setting 10 pairs of cross cables, the displacement amount of the middle tower decreases by as high as 51%. The stiffness of the multi-tower cable-stayed bridge increases with an increase in the number of cross cables, but the increasing trend of stiffness gradually slows down. Increasing the stiffness of the tower or beam can improve the structural stiffness to a certain extent, but the effect is much less potent than that of the cross cable in the middle span. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Combined Joint and Member Damage Identification of Semi-Rigid Frames with Slender Beams Considering Shear Deformation

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Buildings 2023, 13(7), 1631; https://doi.org/10.3390/buildings13071631 - 27 Jun 2023

Cited by 2 | Viewed by 364

Abstract

A damage identification methodology considering shear deformation was presented in this paper to identify damage to semi-rigid frames with slender beams. On the basis of the successful identification of structural joint damage, the combined joint and member damage of the structure was identified. [...] Read more.

A damage identification methodology considering shear deformation was presented in this paper to identify damage to semi-rigid frames with slender beams. On the basis of the successful identification of structural joint damage, the combined joint and member damage of the structure was identified. The objective function was formulated to minimize the discrepancies between the analytical and measured nodal displacements. Damage identification was performed on semi-rigid frame structures with different cross-sectional shapes, and the results were compared with those of ignoring shear deformation. Several frame structures were employed to verify the advantages and efficiency of the proposed method. The results demonstrate that the present method could significantly improve the accuracy of damage identification for semi-rigid frames compared with the method ignoring shear deformation. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

In-Plane Failure Mechanism and Strength Design of Plate-Tube-Connected Circular Steel Arches

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Xigui Yuan

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Bo Yuan

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Minjie Shi

Buildings 2023, 13(4), 956; https://doi.org/10.3390/buildings13040956 - 03 Apr 2023

Viewed by 629

Abstract

The in-plane elastoplastic failure mechanism of plate-tube-connected steel circular arches with inverted triangular cross sections is investigated in this study by using theoretical derivation and numerical simulation. First, the in-plane elastic buckling load formula of the arch under full-span uniform radial load (FSURL) [...] Read more.

The in-plane elastoplastic failure mechanism of plate-tube-connected steel circular arches with inverted triangular cross sections is investigated in this study by using theoretical derivation and numerical simulation. First, the in-plane elastic buckling load formula of the arch under full-span uniform radial load (FSURL) is presented. Then, the limited conditions of avoiding the connecting plate and chord local failure before global elastic instability are derived. Lastly, the elastic–plastic failure mechanisms of arches are studied under FSURL, full-span uniform vertical load (FSUVL), and half-span uniform vertical load (HSUVL). It is found that the arch will experience global failure, chord local failure, combined connecting plate and chord failure, and connecting plate local failure under FSUVL and HSUVL. The failure mode is mainly related to the stiffness of the connecting plate. The corresponding design formulas are proposed for the global failure of arches and local failure of the chord. The proposed formulas and FE results are in good agreement. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Research on Seismic Performance of 735 MPa High-Strength Reinforced Concrete Frame Joints

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Buildings 2023, 13(2), 320; https://doi.org/10.3390/buildings13020320 - 20 Jan 2023

Viewed by 650

Abstract

To study the seismic performance of high-strength reinforced concrete frame joints, cyclic loading tests were carried out on six concrete beam-column joints configured with the new Cold-rolled Ribbed Bar (CRB) 735 high-strength steel reinforcement and one joint with Hot-rolled Ribbed Bar (HRB) 400 [...] Read more.

To study the seismic performance of high-strength reinforced concrete frame joints, cyclic loading tests were carried out on six concrete beam-column joints configured with the new Cold-rolled Ribbed Bar (CRB) 735 high-strength steel reinforcement and one joint with Hot-rolled Ribbed Bar (HRB) 400 ordinary steel reinforcement to obtain the effects of the axial compression ratio and the stirrup ratio in the joint core on the seismic performance of the joints. The test results show that the following: (1) Increasing the axial compression ratio can improve the energy dissipation characteristics of the joints configured with CRB735, but cannot effectively improve the ultimate shear capacity of the joints. Larger axial compression ratio will cause earlier cracks in the core area and reduce the ductility of the specimens by 6.1~27.9%. (2) Increasing the stirrup ratio in the joint core will increase the shear capacity of the joint by 5.3~8.1% while also increasing the failure displacement by 2.8~14.9%. (3) When the joints are configured with CRB735 stirrups, the rate of stiffness degradation from core cracking to the yielding stage of the specimens will be effectively delayed. (4) Compared with the joint configured with HRB400, the ultimate loading process of the joints using CRB735 is shorter, the yield load and yield displacement are higher, and the specimens are close to the ultimate state when they reach yield. Finally, the shear capacity of concrete beam-column joints configured with CRB735 can be calculated using the relevant shear capacity equation in GB50010-2010 Code for Design of Concrete Structures, and has a certain safety reserve. In the equation, the yield strength of CRB735 steel reinforcement is recommended to be 735 MPa. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Analysis of Axial Compression Performance of Concrete Stub Column with CRB600H Stirrups

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Buildings 2023, 13(1), 195; https://doi.org/10.3390/buildings13010195 - 11 Jan 2023

Viewed by 828

Abstract

The CRB600H reinforcement is a new type of cold-rolled ribbed steel bar, which has the advantages of green and low carbon, stable quality, saving precious metal resources and so on. In order to study the axial compression performance of short concrete columns with [...] Read more.

The CRB600H reinforcement is a new type of cold-rolled ribbed steel bar, which has the advantages of green and low carbon, stable quality, saving precious metal resources and so on. In order to study the axial compression performance of short concrete columns with CRB600H stirrups, the finite element analysis model of high-strength reinforced concrete stub columns was established by using ABAQUS, and the accuracy of the finite element model was verified by literature experiments. The effects of stirrup construction (Type A, B and C), stirrup spacing and concrete strength on the axial compressive bearing capacity and ductility of concrete columns with CRB600H stirrups were analyzed and compared with HRB400 stirrups columns. The results showed that the peak bearing capacity of the specimens with CRB600H stirrups was similar to that with HRB400 stirrups, and the ductility of the specimens was improved with CRB600H stirrup. Compared with the type A stirrup and type C stirrup, the type B stirrup had the best concrete restraining effect, and the ductility and peak bearing capacity of the specimens were higher. With a decrease in the stirrup spacing, the ductility and peak bearing capacity of the specimens increased. With an increase in concrete strength, the peak bearing capacity increases, but the ductility decreases. Through parameter analysis, a formula for calculating the axial bearing capacity of 600 MPa high-strength stirrup concrete stub columns based on the effective confinement index (k_eλ_t) was proposed. It is suggested that the equivalent volume of a HRB400 stirrup can be replaced by a CRB600H stirrup in the actual project. At the same time, when the high-strength stirrup was used, the restraining effect of the stirrup on concrete should be considered in the calculation of the axial compression bearing capacity. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Study on Eccentric Compressive Behavior of Concrete Columns Reinforced with NPR735 High-Strength Steel Bars

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Buildings 2023, 13(1), 188; https://doi.org/10.3390/buildings13010188 - 10 Jan 2023

Cited by 2 | Viewed by 1160

Abstract

In this paper, eccentric compressive tests and theoretical studies of grade 735 MPa reinforced concrete columns were conducted. The eccentric distance and strength of the longitudinal reinforcement were used as experimental parameters to investigate the bearing capacity, failure mode, and strength of eccentric [...] Read more.

In this paper, eccentric compressive tests and theoretical studies of grade 735 MPa reinforced concrete columns were conducted. The eccentric distance and strength of the longitudinal reinforcement were used as experimental parameters to investigate the bearing capacity, failure mode, and strength of eccentric compressive behavior of NPR735 high-strength steel bars. When the load eccentricity of the reinforced concrete columns was small or longitudinal, the reinforcement ratio was large, and small eccentricity failure occurred. The results were similar to the failure mode of ordinary concrete columns with traditional steel bars. When the load eccentricity decreased, the bearing capacity increased, but the deflection and ductility of the specimen decreased. When the strength of the longitudinal reinforcement increased, the bearing capacity of the specimen increased slightly. Finally, according to current design methods in the concrete structure design code, the bearing capacity of the eccentric compressive column was obtained, and the calculated results were compared with the experimental results to verify the applicability of the concrete structure design code GB50010-2010 to concrete columns with grade 735 MPa reinforcement. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Peak Stress Method-Based Fatigue Predictions for Steel Crane Girder Variable-Section Supports

by

Xiaoqing Zhao

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Kuntao Xing

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Nan Jin

Buildings 2023, 13(1), 108; https://doi.org/10.3390/buildings13010108 - 31 Dec 2022

Cited by 2 | Viewed by 885

Abstract

Engineering applications have shown that variable-section supports of steel crane girders are prone to fatigue fracture, and traditional fatigue prediction experience is not applicable to these types of supports due to the complex internal stresses caused by their unique geometries. In this paper, [...] Read more.

Engineering applications have shown that variable-section supports of steel crane girders are prone to fatigue fracture, and traditional fatigue prediction experience is not applicable to these types of supports due to the complex internal stresses caused by their unique geometries. In this paper, a new fatigue prediction approach was proposed for variable-section supports of steel crane girders based on the peak stress method; this approach can locate the fatigue initiation sites and predict the fatigue lives of variable-section supports under axial and bending loading. Then, some constant-amplitude fatigue test results were presented for typical variable-section supports of steel crane girders. A comparison was made between the experimental results and theoretical estimations using the peak stress method. The results indicated that the peak stress method is appropriate to estimate fatigue life up to crack initiation in variable-section supports of steel crane girders subjected to axial and bending loads. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Plated versus Corrugated Web Steel Girders in Shear: Behavior, Parametric Analysis, and Reliability-Based Design Optimization

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Buildings 2022, 12(12), 2046; https://doi.org/10.3390/buildings12122046 - 22 Nov 2022

Cited by 3 | Viewed by 1028

Abstract

Unlike straight web I-girders, the construction industry’s demand for corrugated web steel girders is increasing due to their high shear strength without needing transverse stiffeners. Although the corrugation fabrication cost could be high, savings on material, transportation, and erection costs can compensate for [...] Read more.

Unlike straight web I-girders, the construction industry’s demand for corrugated web steel girders is increasing due to their high shear strength without needing transverse stiffeners. Although the corrugation fabrication cost could be high, savings on material, transportation, and erection costs can compensate for the expenditures needed to build flat-plated girders with stiffeners. This study investigates the shear behavior of straight and corrugated webs with different geometries and corrugation profiles (triangular and trapezoidal) through laboratory testing. Following a detailed parametric study, the results of the experimental program were used to formulate a reliability-based design optimization (RBDO) problem to achieve target reliability. When applied to two case studies related to girders of a building and a bridge, the RBDO demonstrated that it is possible to design girders with corrugated webs to achieve economic designs in terms of material volume in the range of 20% to 40% with thinner webs and without the need for transverse stiffeners. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Experimental Study on the Overall Stability of Corroded H-Shaped Steel Beams

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Buildings 2022, 12(11), 1923; https://doi.org/10.3390/buildings12111923 - 08 Nov 2022

Cited by 3 | Viewed by 1082

Abstract

The degradation of the overall stability of corroded rolled H-shaped steel beams under bending conditions has not been extensively studied. In the present study, monotonic tensile tests and overall stability tests were conducted on seven rolled H-shaped steel beams that were subjected to [...] Read more.

The degradation of the overall stability of corroded rolled H-shaped steel beams under bending conditions has not been extensively studied. In the present study, monotonic tensile tests and overall stability tests were conducted on seven rolled H-shaped steel beams that were subjected to electrochemical corrosion in order to discuss the influence of corrosion on the material’s mechanical properties and the overall stability of steel beams under bending conditions. The test results have indicated that the strength, the elastic modulus, and the elongation of the steel declined with an increase in the corrosion rate of the steel beams, and an obvious plastic deterioration phenomenon was observed. In addition, all of the steel beams with different degrees of corrosion were subjected to overall flexural–torsional buckling failure. The stiffness and the overall stability ultimate bearing capacity of the corroded steel beams decreased with the increase in the corrosion rate, and the overall stability of the test beams with a high design corrosion rate degraded significantly. Furthermore, by using the finite element numerical simulation analysis software ABAQUS, a double-reduction corrosion model of the sectional dimensions and the material’s mechanical properties was established. The overall stability ultimate bearing capacities of the steel beams that were subjected to three-point bending and the corresponding load–lateral displacement curves were analyzed. In addition, the finite element numerical simulation results were compared with the test results for verification. Subsequently, the influence of the initial bending on the overall stability ultimate bearing capacity of the steel beams was analyzed by virtue of the verified finite element model. This study will provide a test basis for the evaluation of the bearing capacity of existing rolled H-shaped steel members, as well as an experimental basis and finite element model reference for the follow-up study on the degradation of the mechanical properties of the corroded rolled steel members. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

Bearing Behavior of Axially Compressed High-Strength Steel Columns in Precipitator Casing Considering the Stressed-Skin Effect of Wallboard

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Buildings 2022, 12(10), 1737; https://doi.org/10.3390/buildings12101737 - 19 Oct 2022

Viewed by 922

Abstract

To explore the application feasibility of high-strength steel in skeleton columns of precipitator casing structures, the bearing behavior of axially compressed H-section high-strength steel columns was investigated by the nonlinear finite element method by considering the stressed-skin effect of wallboard. When the column [...] Read more.

To explore the application feasibility of high-strength steel in skeleton columns of precipitator casing structures, the bearing behavior of axially compressed H-section high-strength steel columns was investigated by the nonlinear finite element method by considering the stressed-skin effect of wallboard. When the column yield strength does not exceed 460 MPa, the column undergoes elasto-plastic interactive buckling, which means the steel strength can be fully utilized. For the column strength of 550 MPa or 690 MPa, the wallboard yield failure occurs, owing to excessive loading of the relatively weak wallboard, and column stress magnitude is usually in the elastic range without the full utilization of steel strength, whereas if the wallboard is stiff enough, columns will still undergo buckling failure. A welding residual stress measuring test was conducted to validate the residual stress generation simulation via the thermal-mechanical coupling finite element method. Concerning the geometrical imperfections and residual stresses, it was found that their influence becomes less severe when the column steel strength increases. The bearing capacity can be improved by increasing the wallboard thickness and stiffener stiffness, or reducing the wallboard width, the stiffener spacing, the width-to-thickness ratio of column flange, the height-to-thickness ratio of column web, and column torsional slenderness ratio. Column material can be fully utilized when column steel strength does not exceed 460 MPa. Hence, employing high-strength steel is reasonable. When the column steel strength is equal to or higher than 550 MPa, wallboard strength should be sufficient to ensure that the column failure occurs before wallboard failure. In such cases, high-strength steel should be used carefully. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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Open AccessArticle

A Technique for Optimizing the Sequences Yielding under Load of Concentrically-Braced Steel Frames

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Buildings 2022, 12(10), 1656; https://doi.org/10.3390/buildings12101656 - 11 Oct 2022

Viewed by 1741

Abstract

Concentrically-braced steel framing is widely used in tall buildings. Designing with adequate but not excessive seismic resistance is a challenge because of the limited experience of seismic failure and the huge variety of components used. A quantitative method for defining an acceptable range [...] Read more.

Concentrically-braced steel framing is widely used in tall buildings. Designing with adequate but not excessive seismic resistance is a challenge because of the limited experience of seismic failure and the huge variety of components used. A quantitative method for defining an acceptable range of component parameters is proposed and tested using published experimental data and finite element modeling. The method involves the structural yield mechanism control method of the steel concentrically-braced frame. It is proposed by inequality iteration of different structural components’ bearing capacities. It generates acceptable ranges for the parameters defining the properties of the columns, beams, and braces. The test results show that concentrically-braced steel frames designed within the recommended ranges will have the desired sequence of component yielding. The sequence is, however, highly sensitive to components’ parameter values. In practical engineering stochastic variability in the parameters must be considered. Full article

(This article belongs to the Special Issue Advances in Steel Structures: Testing, Modelling and Design)

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