Hysteretic Performance Research Articles

Numerical modeling and experimental validation of Sliding-LRBs considering hysteretic strength degradation

To investigate the refined hysteretic response of the Sliding-LRB subjected to cyclic loadings, an advanced numerical model with HSD is developed based on the OpenSees platform. The hysteretic performance of the Sliding-LRB is numerically investigated under cyclic loadings and validated by the experimental results accordingly. In particular, various loading conditions, e.g., vertical loading, loading frequency and shear displacement amplitude are considered to conduct the numerical study and the numerical results are compared with the experimental counterparts. The key hysteretic characteristics, including the energy dissipation in each cycle, equivalent stiffness and damping ratio, are compared to demonstrate the accuracy and effectiveness of the developed numerical model of the Sliding-LRB. Results show that the developed numerical model can effectively predict the hysteretic behavior of the Sliding-LRB under cyclic loadings, and the numerical results match well with that of the corresponding experimental values. The numerical model representations of the Sliding-LRB are then achieved based on the numerical and experimental results.

The effect of design parameters on mechanical performance of all-steel buckling restrained brace with double steel tubes

To explore the effect of design parameters on the mechanical performance of the proposed all-steel buckling-restrained brace (BRB), the finite element software ABAQUS is adopted. The brace consists of an inner round steel tube and an outer square steel tube to restrain its inner core, designed with both the cruciform-section core and the H-section steel core. Quasi-static tests are performed on the all-steel BRB to explore its energy dissipation capacity. The cyclic behavior of the specimen models is evaluated. The validity of the numerical model is verified by comparing the predicted results with the experimental results. Next, the effects of three parameters on the mechanical properties of the brace—the width-thickness ratio of the inner core, the clearance between the inner core and the inner round steel tube c1, and the constraint ratio—are investigated by the validated numerical model. The width-thickness ratio varies from 6 to 20, the gap value ranges from 1 to 7 mm, and the constraint ratio ranges from 0.43 to 1.03. Results show that the hysteresis curves of the two braces are full, with stable hysteretic performance and good energy dissipation capacity, which justifies the construction. Based on the parameters analysis results, the optimum values of the width-thickness ratio, gap, and constraint ratio have been recommended for steel BRBs.

Performance optimization and loading rate-dependency of friction dampers with non-metallic friction materials

Non-Asbestos Organic (NAO) is widely used in automobile braking systems due to its low cost and stable performance. Meanwhile, NAO is also suitable for seismic energy dissipation of building structures, but further research was required. Configuration and loading rate are significant factors affecting the hysteretic performance of the friction damper. Thus, cyclic loading tests were conducted to evaluate the friction behavior of friction dampers with non-metallic friction pads (Non-Asbestos Organic (NAO) and Polytetrafluoroethylene (PTFE)), and the friction pairs were NAO-Steel and PTFE-Steel, respectively. A total of 13 specimens were designed to comparatively analyze the effects of the following factors on the mechanical performance of the friction damper: the configuration of the friction damper, loading rate, and reloading process after a reassembly. Firstly, some unnecessary friction needed to be avoided to keep the stable performance of the damper, such as the contact friction between the slot of the inner steel plate and friction pads or bolts. Secondly, the normal force of both NAO and PTFE friction dampers reduced gradually during the loading process. The former showed a higher cumulative loss rate, which increased with the initial nominal pressure. Again, the dynamic friction coefficients of NAO and PTFE friction dampers tended to be constant under high-speed loading, which was remarkably higher than that under low-speed loading. The dynamic friction coefficients of NAO and PTFE friction dampers were suggested to be 0.229 and 0.121 for structural analysis, respectively. Finally, compared with the first test of the friction damper, the reloading test results after a reassembly showed excellent reusability of both NAO and PTFE friction dampers.

Metoda projektiranja i inženjerska primjena posmičnih zidova s tarnim prigušivačem seizmičke energije

At present, the target of seismic strengthening is to gradually work towards the objective of being able to quickly restore function, and even replace function after an earthquake. In addition, the foot of reinforced concrete shear walls is easily damaged in shear wall structures. If a damper is set in this part, it can ensure the normal stiffness and energy consumption function of the shear wall, and it can be easily and conveniently replaced after an earthquake at a low cost, which is an important measure to realize recoverable functional cities. Therefore, a new type of friction energy dissipation damper has been designed. First, the components of the damper are described, and the design process, including the base placement area, bolt hole length, and initial slip force, is theoretically analysed. Then, on the basis of a shear wall test, SAP2000 is used to analyse and verify correctness of the model. Furthermore, the dampers are placed in the corner of the shear wall for remodelling. Considering different bolt hole lengths, the hysteretic performance, bearing capacity attenuation, stiffness degradation, and energy dissipation capacity of the model are compared and analysed. The results show that the friction energy dissipation damper can improve the energy dissipation capacity and delay the stiffness degradation and bearing capacity attenuation of the structure. This study provides a theoretical basis for a more detailed engineering design and application.

Cyclic response of RC beam-column joints strengthened with transverse steel bars and with C-FRP diagonal ties

The use of additional bars, internally placed through drill holes, in external beam-column connections subjected to cyclic loading, as shear reinforcement is experimentally investigated.The presented experimental work includes tests of full-scale specimens with different reinforcement arrangements in the joint area, they are as follows: (a) the JB0V control specimen with two (extra) vertical side bars without shear reinforcement in the joint area and, (b) the JB0R joint, same as in the case of the control specimen, without the extra vertical bars, but with four additional steel bars that were placed in holes, which were drilled through the concrete of the joint body for this purpose, (c) the JB0VFX joint, the damaged control specimen repaired and strengthened with C-FRP diagonal ties (rope connections) through the joint area. The effectiveness of these additional bars and ropes as a shear reinforcement on the overall seismic performance of the tested joint is examined.A comparison between the test results of the examined specimens indicated that the applied retrofitting technique is appropriate for the enhancement of the overall hysteretic performance of the beam-column joints in terms of load carrying capacity, stiffness and hysteretic energy dissipation.

Effects of various reinforcing intra-module connection details on seismic behavior of corner-supported steel modular buildings

The rib stiffeners are usually used to reinforce the intra-module connections in corner-supported modular steel buildings; however, may be conflicted with the internal wall panels. There is a lack of relevant understanding of the effects of reinforcing intra-module connections on the seismic behavior of corner-supported steel modular structures. Therefore, this study investigated the effect of the intra-module connections reinforcing details on the seismic behavior of such modular structures. Such proposed reinforcing measures comply well with the architectural internal finishing demand, including vertical stiffeners or cover plates and an enlarging ceiling beam section. Four full-scale two-story plane frame structures were designed and experimentally examined under lateral cyclic loading to investigate and compare their seismic performance, such as the hysteretic performance, skeleton curves, and strain distribution. The experimental results showed that these reinforcing measures were helpful for the development of plastic deformation of such corner-supported modular structures through effectively moving local buckling away from the beam ends. Moreover, the reinforcing intra-module connection details were able to enhance the force resisting capacity and initial lateral stiffness of the overall structures. Additionally, the nonlinear finite-element (FE) modeling was developed and validated against the corresponding experiment. It showed satisfactory agreement with the failure responses and load–displacement curves. The plastic strains at reinforcing intra-module connection were further analyzed through the validated FE models, and the design suggestions were given accordingly.

Experimental and Numerical Study of Energy Dissipation Components of a New Metallic Damper Device

PurposeThe novel metallic damper device for passive vibration control of structures, which is designed primarily for seismic protection of buildings, is described in this paper. It consists of the base plate, fixed into foundation, with two concentric cycles of vertical components and a middle steel activating plate anchored to the isolated structure. During an earthquake, the middle steel activating plate moves together with main structure causing bending of vertical components. Seismic energy is absorbed due to plastic deformation of the vertical components of the damper. The performance of various vertical components, the key elements of the novel damper is studied in this paper. The advantages of this type of damper reflect in its ability to adapt its own features depending on the intensity of the earthquake and that it has equivalent characteristics in every horizontal direction due to rotational symmetry.MethodsSixteen experimental tests of the vertical components of the damper, were conducted to obtain their hysteretic behaviour. Numerical models using the finite element method and the Abaqus/Standard software were developed, validated and verified with experimentally obtained results.ResultsThe experimental results show significant energy absorption of the vertical components of the novel damper. Numerical models can be used in further research instead of expensive experimental tests.ConclusionsThe vertical components of the novel damper possess extraordinary hysteretic performance. If the components of the energy dissipation device are properly designed for maximum displacements, the device is not expected to suffer heavy damage or total failure during earthquakes.

Experimental and analytical investigation of drilled flange connections (DFCs) with radial drilling patterns

The capability of reduced beam sections (RBS) to improve the seismic behavior of rigid connections leads to their notable application in steel moment-resisting frames. However, they may encounter shortcomings such as local buckling and lateral-torsional buckling. To resolve such problems, the idea of utilizing perforated beam flanges instead of cut-out flanges as reduced beam sections was presented. These type of connections can reduce the potential for local and lateral-torsional buckling of conventional RBS connections and improve their seismic performance. Achieving such advantages requires special care to geometrical specifications and drilling patterns (DPs). Appropriate arrangement of holes reduces the stress concentration around the beam flange-to-column Complete Joint Penetration (CJP) groove weld and, consequently, prevents the groove weld and inter-hole area from tearing and fracturing in early cycles of loading. The present study investigated the hysteretic performance of the drilled flange connections (DFCs) of various drilling arrangements through an experimental program.It should be noted that the box-shaped columns were considered in this study to target the 3D moment resisting frames (MRFs) that all their axes participate in the lateral force-resisting system. The most appropriate drilling patterns were selected using remarkable numbers of numerical analyses. Four laboratory specimens with different drilling arrangements of top and bottom flanges were fabricated based on preliminary numerical analyses. The laboratory specimens were subjected to cyclic loading. To evaluate the specimens' seismic performance, moment-rotation hysteresis curves were compared, and the stress distribution at the connection CJP groove welds. The results of the experimental tests revealed that those DFCs with combined DP with notches and holes (DFC1), radial DP (DFC2), semi radial DP with notches (DFC3), and semi radial DP (DFC4) could increase the rotational capacity of the DFCs up to 50% of the required rotation of the special moment-resisting connections. Moreover, semi radial DP (DFC4) may increase the connection's rotational capacity up to 75% of the special moment-resisting connections. Also, Based on the analytical results, conventional RBS connections may increase the 0.04 radians, needed rotational capacity up to 37.5% for a pre-qualified moment-resisting connection. It was also shown that no lateral-torsional buckling and smaller degradation in stiffness and strength took place in plastic hinge zones at the relative deformation of 0.04 radians. The plastic strain at the center of the CJP groove weld line in the beam longitudinal direction was more significant than those corners of the groove weld line in the same direction. In all specimens, the minimum plastic strain of the CJP groove weld took place in central parts of the weld in the transverse direction. In DFC1, DFC2, DFC3, and DFC4 specimens, the contribution of panel zone rotation in the overall plastic rotation of the connection is negligible.

Seismic Behavior of a Steel Beam-to-Concrete-Filled Steel Tubular Column Connection Using External Diaphragms

This paper investigates the seismic behavior of a steel beam-to-concrete-filled steel tubular column connection with external diaphragms. In addition to the multiple advantages observed for manufacturing and assembly, this type of connection is expected to provide an adequate plasticizing mechanism based on its ductility, energy dissipation and moment resistance capacity. However, guidelines have not been provided for this type of connection within the AISC 358 standard, which makes experimental studies under cyclic loads necessary. This work presents such a study, which was carried out in accordance with the FEMA 350 standard for earthquake-resistant structures. The results for the failure modes, hysteretic performance, strength and stiffness degradation, rigidity classification and energy dissipation are provided and analyzed. The results indicate that this connection exhibits large hysteretic loops and develops ductility and dissipation capacity, as expected. More importantly, the maximum rotation of the beam was 0.07 rad with a resistant moment above 80% of the beam capacity measured from the face of the column. Thus, the ductility design requirements for earthquake resistance are met according to the current regulations. Consequently, the proposed connection is suitable for use in special moment frame structures located in areas of high seismic threat.

Experimental and theoretical analysis of novel shear - Flexural combined metallic damper

Energy devices are generally installed to improve the structural energy dissipation capacity and damping with the aim of absorbing the input energy and decreasing the damage of the parent structure. One of the most widely employed energy devices is metallic damper. This paper proposed a novel shear - flexural combined (SFC) metallic damper, in which the shear plate was clamped by the flexural plates on both sides to engender the interactive work between them. One pure shear and four SFC dampers were prefabricated with the identical nominal yield strength. Different shear - flexural thickness ratios (ts/tf) and spaces of flexural plates (s) were applied for the tested specimens. Cyclic tests were then performed to reveal their hysteretic performance and mechanical behavior. Strain distributions of shear and flexural plates indicated that the flexural plate provided satisfactory constraints for the shear plate to form local buckling between the adjacent two flexural plates in the post buckling stage. A high ts/tf might lead torsional failure of flexural plates due to the contact force induced by the buckled part of shear plate. More importantly, a modified force - displacement model was proposed to predict the mechanical behavior of SFC dampers. The buckling strength of shear plate was discussed to make the modified model coincide well with the experimental data. The experimental and analytical results confirmed that the proposed SFC damper had superior seismic performance and was suitable to be employed in building structures in earthquake regions.

Experimental study on the cyclic behaviour of shear links made of BLY160 steel

The cyclic behaviour of shear links made of a new type of low-yield-point (LYP) steel BLY160 is intensively investigated. A total of twelve specimens are designed to evaluate the influence of material type, web compactness, link flange, web stiffeners, restraining ribs of the web panel and link length ratio on force transfer mechanism of shear links. Based on the analysis of the failure mode and process, hysteretic performance, strain distribution and development of test specimens, it is found that the excellent mechanical properties of the BLY160 steel have enabled the shear link to yield at a lower strength and reach an inelastic rotation capacity as large as 0.16 rad. Introducing the link flange and reducing the link length ratio can effectively improve the seismic performance of the shear link. Due to the strain-hardening phenomenon of BLY160 steel, the overstrength factors of shear links have reaches 1.70 to 2.02, and is gradually increasing with the reduction of link length ratio. The current design provisions can be applied to calculate the yield strength of shear links with a link length ratio smaller than 2.0. Except for the shear links with diagonal web stiffeners or composed of traditional steel, all the shear links have reached an equivalent damping coefficient exceeding 0.50. Finally, an isotropic–kinematic combined hardening restoring force model is proposed to simulate the cyclic behaviour of shear links made of BLY160 steel, the feasibility and accuracy is verified by comparing the predicted hysteretic curves and test results of shear links with different forms.

Behavior of CFST Column to Concrete-Filled U-Shaped Steel Beam Joints with Slabs under Cyclic Loading

This study proposes a through-beam composite joint system to connect square concrete-filled steel tubular (CFST) columns and concrete-filled U-shaped steel (CFUS) beams. In the joint system, channel-shaped holes in the square steel tube allow direct load transfer of the beam. Two procedures for constructing the joints, denoting two types of joint details (i.e., Type-I and Type-II), are proposed to facilitate field installation. Six cruciform joints were tested under combined constant axial compression and cyclic lateral loading. Three Type-I joints were tested. The main test parameters were the loading procedure and the axial load ratio applied on the CFST column. All Type-I specimens reached their beam flexural capacities followed by the fracture of fillet welds at beam ends, as well as the fracture of the reduced steel section within the joint zone. Three Type-II joints were constructed with the same column and beam section dimensions as the Type-I specimens. The main test parameters were the additional flexural rebars at beam ends and the axial load ratio. All Type-II specimens reached their beam flexural capacities, followed by the fracture of the heat-affected zone at beam ends. All specimens failed in a ductile manner, had favorable hysteretic performance, and complied with the acceptance criteria. Design considerations are proposed based on the test and analysis results.

Hysteretic Behavior and Multi-Wave Buckling of Assembled Buckling-Restrained Braces Wrapped with Fiber Clothes

To rapidly repair the damaged buckling-restrained brace serving as energy absorption member during earthquake, the assembled method of wrapping the component with FRP cloth is proposed. In this research, a series of cyclic tests on six assembled buckling-restrained brace (ABRB) wrapped with three kinds of FRPs (carbon fiber, glass fiber and basalt fiber) were performed. The tested results show that all the specimens show excellent hysteretic performance and similar damage mode, namely core unit fracture, whilst short specimens show better ductility, but worse energy dissipation ability than the long specimen. A parametric analysis is performed based on a finite element model validated against the test result. The effects of the gap and friction force between core unit and infilled concrete and the thickness of FRP cloth are analyzed. The modes of multi-wave buckling of core units are exhibited, and the influence of multi-wave buckling on component performance is evaluated. Based on the test and simulation analysis, CFRP is suggested to be used in the wrapped buckling-restrained brace.

Hysteretic performance of dovetail profiled steel–concrete composite sandwich shear walls

Dovetail profiled steel–concrete composite sandwich shear wall (DPCW) is a novel composite member with the potential to serve as a lateral-resisting member in buildings. The DPCW is composed of two dovetail profiled steel sheets (DPSs) and concrete in between. The dovetail-shaped ribs of DPSs embedded in the concrete can not only enable the steel–concrete composite action without additional connectors but also improve the ductility of the shear wall due to the presence of vertical dovetail-shaped slits in the concrete panel. However, there were limited investigations regarding its hysteretic behaviour. In this paper, the hysteretic performance of DPCWs was investigated by experiments and numerical studies. Six DPCW specimens with different axial compression ratios and shear span ratios were tested subjected to the combined axial and cyclic lateral loads. All specimens failed in a ductile manner with failure modes of local tension fields developed on strips of the DPSs and crushing of concrete at the top and bottom between the dovetail-shaped slits. With the increase of axial compression ratio, the lateral stiffness was increased but the ductility was reduced. Both the deformability and energy dissipation capacity of DPCWs were improved with the increase of the shear span ratio. Then, numerical studies using the commercial software package ABAQUS were performed to further investigate the failure mechanism of DPCWs and the effect of the shear span ratio and axial compression ratio on its lateral behavior. Moreover, based on experimental results and FE analysis, a simplified model was established for evaluating the lateral resistance capacity of DPCWs. The proposed prediction formulae were found to agree with the test results with no more than an 8% discrepancy.

RC structures life-cycle probabilistic evaluation method considering mesoscopic material uncertainty with chloride ingress

Due to the attack of harmful environmental substances, the reinforcements in concrete can be corroded. The corrosion of reinforcements induces the concrete crack and the reduction in structural capacity. The complex durability deterioration at the material scale is commonly oversimplified in the structural analysis, and the influence of reinforcement corrosion distribution can hardly be evaluated in traditional methods. Benefitted from the accurate material model and efficient solution technologies, a structural life-cycle probabilistic evaluation method is proposed based on the material uncertainty influence. The computational framework consists of three steps. First, the simulation of chloride ingress in structural cross-section considering mesoscopic variation; second, the finite element analysis of structural response with modifying reinforcement corrosion states; third, the structural life-cycle performances are evaluated probabilistically with the trained Artificial Neural Network model. Focussed on the life-cycle hysteretic performance of the reinforced concrete column, the whole procedure is operated for illustration, and the time-dependent decreasing structural performance are investigated. Compared with widely used macroscopic methods, the model precision can be refined over 90%. By discussion effects of different measures to improve structural performance are studied, including increasing concrete strength and concrete cover. The results show that the thicker concrete cover can postpone the initial deterioration and significantly increase structural life-cycle performance probabilistically, and with the same designed action effect, the structural service life can be extended over 85% to reach same reliability.

Seismic performance of prefabricated beam-to-column joint with replaceable energy-dissipating steel hinge

This study presents a novel energy-dissipating prefabricated joint for connecting beam to column in a precast frame structure. The joints are characterized by a replaceable steel hinge and a prefabricated steel tube confined joint core, providing advantages for precast concrete reinforced frames, such as complete assembly, damage control, and maintainability of the structure after an earthquake. The hysteretic behavior of the proposed prefabricated joint was studied through two tests. First, a full-scale prefabricated joint was tested under cyclic loading until failure. On the basis of the initial test, only four weakened dissipaters of the steel hinges in the prefabricated joint were replaced and the second test was conducted to investigate the restorable functional characteristics of the proposed prefabricated joints. For comparison, a reference monolithic joint was also tested. The experimental results demonstrate that the novel prefabricated beam-to-column joint displayed excellent hysteretic performance, and corresponding to the monolithic joint, the load-bearing, energy dissipation, and deformation capacity were improved. The damage of the prefabricated joint was concentrated on the weakened dissipaters of the steel hinges, indicating that the failure mode and damage degree of the prefabricated joint can be controlled. In the second test, the prefabricated joint exhibited similar hysteretic behavior to that of the first test; however, the initial stiffness was slightly lower. Therefore, the prefabricated joint can meet the replaceability requirement and achieve satisfactory beam-to-column joint function recovery after an earthquake.

Experimental and numerical investigation of prefabricated prestressed vertical steel strand core tube flange column connection joint

The core tube flange column joint is proposed to avoid field welding of traditional steel structures and to realize remote processing and efficient assembly. However, when the story drift is large, the joint will produce large deformation, and the flange bolt will be broken. Thus, in the present study, a prestressed vertical steel strand core tube flange column connection joint and design criteria were proposed to limit the large deformation at the flange connection. Both proposed prestressed vertical steel strand core tube flange column joint and core tube flange column connection joint were analyzed under low cycle reciprocating loading tests. It was found that the vertical steel strand can improve the hysteretic performance and ductility of the joint. Also, the vertical steel strand can increase the synergistic performance of the column connection joint, which changes the failure mode of the vertical steel strand. Based on the test results, the mechanism of the prestressed vertical steel strand core tube flange column joint was analyzed, and an effective numerical model for the joint was established. The analysis of the joints with different initial steel strand forces showed that increasing the initial short strand force will limit the deformation at the flange connection. Although this restriction has little impact on the joint's bearing capacity, it greatly impacts the strain at the column foot. Based on the numerical analysis, an optimal initial short strand force was obtained, which could provide a reference for engineering design. Note that the prestressed vertical short strand core tube flange column connection joint has excellent mechanical performances, breaking through the key technology of non-welded connection of vertical members. This proposed connection joint can achieve efficient assembly in practical engineering applications and realize the design goal of “strong joint, weak member”

Hysteretic performance of angle steel connections in a timber-concrete composite system

Timber–concrete composite systems are widely used in Europe, North America, and Australasia, primarily due to their good mechanical performance in terms of statics, dynamics, and seismic response. In addition, the concrete slab provides excellent protection to the timber, making such systems suitable for outdoor application. The seismic performance of timber–concrete composites is normally governed by their ductility and energy dissipation capacity. However, few design codes address the ductility and energy dissipation capacity of timber–concrete composite systems, owing to a lack of reliable performance data. Therefore, further research on the hysteretic performance of timber–concrete composite systems is necessary. In this study, six timber–concrete composite specimens with an angle steel connection of the same size were investigated using reversed cyclic tests. The corresponding failure modes were observed, and the salient features of the connection, i.e., the stiffness, ductility, and energy dissipation, were computed from the test results. The force mechanism of the timber–concrete composite specimens under reversed cyclic load was analyzed. Equations were presented to calculate the yield force and negative force in the same load step. A comparison of the test results and the theoretical results indicated good agreement.

Simulation of Mechanical Properties of Special-Shaped Concrete-Filled Steel Tubular Column and Steel Beam Joints after Fire

To study fire after the mechanical performance of steel girder node special-shaped concrete-filled steel tube column, based on standard ISO - 834 litres of cooling curve, the node temperature field model was established based on finite element software ABAQUS, the compute nodes in the overall uniform temperature field under fire as a result, the reasonable choice of fire after the steel and concrete constitutive model, the temperature field results into the node stress model, considering the factors that influence the whole effect of fire loading in low cycle, the nodes of the finite element model, and contrast analysis of the temperature after the fire of the node and hysteretic performance and ultimate bearing capacity. The results show that the failure modes of special-shaped CFST column-steel beam joints at room temperature and after fire are the same, and the ultimate bearing capacity of the joints after fire decreases significantly by 14.88% compared with that at room temperature.

Research on Hysteretic Behavior of Cold-Formed Thin-Wall Rolled Edge Channel Steel Flexural Members

The finite element software ABAQUS is used to calculate and analyze the mechanical performance of cold-formed thin-walled curved channel steel members under horizontal reciprocating load. Double nonlinear finite element model needs to be considered, the influence of geometric imperfection and residual stress. The accuracy of the results was verified by comparing with the relevant test results. On the basis of controlling the main parameters such as width-thickness ratio, axial compression ratio, slenderness ratio and buckling mode, the numerical simulation results of 9 hysteretic specimens were selected to research the influence of the above factors on the hysteretic performance of the flexural members. The analysis results show that the width to thickness ratio, axial compression ratio and slenderness ratio have great influence on the hysteretic performance of the flexural members. The larger the three main parameters are, the worse the bearing capacity, ductility and energy consumption of the members will be. Therefore, the design should avoid as far as possible to choose a larger width-thickness ratio and slenderness ratio section components.