Refined Finite Element Model Research Articles

Enhancing longitudinal performance in railway suspension bridges through an integrated cable restrainer system

Longitudinal motion is a crucial factor affecting the fatigue life of expansion joints, bearings, dampers and short suspenders in suspension bridges. Traditional control methods relying solely on fluid viscous dampers often magnify the relative displacement between the main cable and the girder (hereafter referred to as relative displacement), leading to fatigue problems in the short suspenders. To overcome these shortcomings, an Integrated Cable Restrainer System is proposed. Firstly, a suspension bridge is described, and both a Refined Finite Element Model (RFEM) and a Simplified Finite Element Model (SFEM) are developed and compared. Subsequently, the effectiveness of three cable measures in reducing the longitudinal motion response and the relative displacement of the bridge is evaluated: the cable central buckle (Type I, connecting the main cable and the girder), the inclined control cable (Type II, controlling the main cable) and the longitudinal control cable (Type III, controlling the girder). Finally, an Integrated Cable Restrainer System integrating type I to type III measures is proposed and compared with FVDs, and its control benefits on train and seismic induced vibration are discussed. The results indicate that the SFEM has a higher calculation efficiency while maintaining comparable accuracy. All three types of cable restrainers are effective in controlling the longitudinal movement of the girder end, although type III increases the relative displacement. The Integrated Cable Restrainer System not only effectively controls longitudinal motion (induced by trains and seismic events) but also reduces the relative displacement at the short suspender positions. By employing the Integrated Cable Restrainer System combined with dampers for controlling longitudinal motion, the undesirable effects associated with damper usage can be effectively mitigated. This research serves as a valuable reference for bridge design and longitudinal motion control in suspension bridges. Data AvailabilitySome or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.

Influence of soil liquefaction effect on seismic failure mechanism of river-crossing simply-supported girder bridges subjected to near-fault ground motions

Soil liquefaction induced by strong earthquake could cause severe failure to bridges, particularly for river crossing simply-supported girder bridges. Consequently, it is an urgent task to clarify the influence of soil liquefaction on the seismic failure of this bridge-ground system. To this end, two-dimensional finite element (FE) simulation method focusing on liquefiable site-structure was validated based on a published centrifuge test at first. Then 2 refined FE models were established for a typical river-crossing simply-supported girder bridge with the only difference whether considering site liquefaction. Near-fault ground motions were selected for nonlinear dynamic analysis. Seismic responses of two models were compared to investigate the influence of soil liquefaction on bridge failure mode. The comparison results indicated that soil liquefaction significantly changed seismic response of bridge-ground system, such as site displacement performance, pile–pier displacement demand, pile–piers bending mode, sliding bearing deformation, leading to higher bridge failure risk and change of failure mode.

Effect of Distributed Loading and Refined Modeling on Wind-Induced Stress Analysis of Long-Span Bridges

Wind-induced stress analysis is essential for evaluating the local failure and fatigue damage of long-span bridges in wind-prone regions. Nevertheless, the accuracy of stress-level analysis can be affected by the choice of wind loading and structure models. This study formulates three scenarios to calculate the wind-induced response of a long-span bridge, incorporating two types of wind load models (lumped force or distributed force) and two types of finite element (FE) models (spine-beam or substructure). Specifically, Case 1 employs the lumped force and beam model, Case 2 adopts the lumped force and substructure model, and Case 3 utilizes the distributed force and substructure model. The aerodynamic parameters for forces and POD pressure modes are obtained through wind tunnel tests. By comparing the wind-induced structural response in terms of global behavior (displacement, acceleration) and local behavior (stress), the influence of wind loading and structure models is discussed. The findings reveal that employing a simplified beam model underestimates local stress, and neglecting wind load distribution leads to further underestimation. Therefore, the refined FE model and distributed wind load models are recommended for the precise assessment of wind-induced stresses in long-span bridges.

Numerical Modelling Strategies for Column Rocking Behavior in Traditional Timber Structures

ABSTRACT As a typical feature of traditional Chinese timber structures, columns with floating foot joints are prone to rocking under horizontal force. The column rocking behavior plays an important role in resisting lateral loads. This paper proposes modelling strategies for the rocking behavior of traditional timber columns. The proposed model can capture the contact state of the column foot via a series of distributed axial springs and the possible sliding via a horizontal spring. It has a lower computational cost than refined finite element (FE) models and is independent of numerical calibration compared to rotational spring models. The modelling strategies were validated against refined FE models and experimental data available in the literature. The principle behavior of the approach was carefully investigated including contact stiffness, distribution modes, spring numbers, column bending effects, and computational efficiency. Results show that the effective compression height of the column foot can take the value of the column radius to determine spring stiffness. Column bending needs to be considered in the mechanical analysis of column foot joints for slender columns. The case study on the lateral stiffness of traditional timber frames confirms the applicability of the proposed model in the structural analysis of ancient timber buildings.

Experimental and numerical study on post-ultimate ductile performance of multi-celled concrete-filled steel tubular walls

As a novel steel-concrete composite wall, the multi-celled concrete-filled steel tubular wall (MCFSTW) has been applied in a substantial number of mid- and high-rise building structures due to its excellent in-plane lateral resistance, sufficient out-of-plane stability capacity, good bearing capacity and convenience in construction. In this paper, six groups of single-cellular members of MCFSTW were tested under axial compression to investigate the post-ultimate ductile performance of MCFSTW. In the process of analyzing experimental data, residual strength and ductility indexes were used to quantify the post-ultimate performance of MCFSTW. It was found that as the width-to-thickness ratio increased, the residual strength and ductility indexes decreased. Then, a refined finite element (FE) model for MCFSTW was established by using the software Abaqus. After comparing the results obtained from the refined FE model with the experimental results in this paper and other literature, the validated FE model was used to further investigate the effect of changing different parameters (concrete strength, steel properties and sectional dimensions) on the post-ultimate ductile performance of MCFSTW. After detailed analysis, the ductility and residual resistance indexes of MCFSTW were found to be linearly correlated with the confinement coefficient. Finally, the prediction formulas of residual resistance and ductility indexes were proposed and they can be used in engineering practice.

Numerical simulations to explore the in-plane performance of discontinuous diaphragms in modular steel buildings

As a new type of building system, modular steel buildings (MSBs) use a unique construction method; obvious discontinuities exist in modular diaphragms, making them quite different from traditional ones. To investigate the in-plane behavior of discontinuous diaphragms, numerical investigations were conducted using both refined finite-element (RFE) models and simplified modeling methods. First, the RFE models were established and analyzed, and their results were compared with experimental data. The nonlinear properties of the intermodule connections were determined based on the sub-models obtained from the validated RFE models. Subsequently, simplified models of the assembled modules with discontinuous diaphragms were created and used to investigate the in-plane load transfer performance. Through numerical investigations, the discontinuous diaphragms were found to not satisfy the rigid floor assumption; the effects of different horizontal connections and upper-floor structures on the discontinuous diaphragms were also analyzed and discussed. The simplified models presented load–displacement curves and displacement distributions very similar to those of the RFE models. Moreover, one analytical model was proposed and discussed based on the simplified models, then a positive correlation was found between the lateral stiffness and displacement distribution of the assembled modules. The proposed simplified modeling method can be an effective tool for studying discontinuous modular diaphragms and their effects on the structural response of MSBs.

Numerical Failure Analysis of Laminated Beams Using a Refined Finite Element Model

AbstractIn the present investigation, laminated composite beams subjected to a bending static loading are studied in order to determine their failure mechanisms and the first ply failure (FPF) load. The FPF analysis is performed using a refined rectangular plate element. The present element is formulated based on the classical lamination theory (CLT) to calculate the in-plane stresses. To achieve this goal, several failure criterions, including Tsai-Wu, Tsai-Hill, Hashin, and Maximum Stress criteria, are used to predict failure mechanisms. These criterions are implemented within the finite element code to predict the different failure damages and responses of laminated beams from the initial loading to the final failure. The numerical results obtained using the present element compare favorably with those given by the analytic approaches. It is observed that the numerical results are very close to the analytical results, which demonstrates the accuracy of the present element. Finally, several parameters, such as fiber orientations, stacking sequences, and boundary conditions, are considered to determine and understand their effects on the strength of these laminated beams.

Experimental and numerical study of T-shaped irregularly concrete-filled steel tube columns under combined axial loads and moments

T-shaped irregularly concrete-filled steel tube column (T-ICFSTC) is formed by I-shaped steel, U-shaped steel and infilled concrete. The I-shaped steel and U-shaped steel are welded together to form a multi-cell CFST column. The T-ICFSTCs can be used in the corner of T-shaped intersection location of two walls in the buildings, which can avoid the exposure of the columns and increase the available area of the indoor space. The overall flexural stability performance of the T-ICFSTCs under axial loads and moments may still be an important problem in engineering design. This paper studies the overall flexural stability performance of the T-ICFSTCs under combined axial loads and moments. Firstly, the experiments of two T-ICFSTC specimens under eccentric loading with eccentric distance of 100 mm and opposite eccentric directions were carried out. Subsequently, the refined finite element (FE) models and the simplified finite element (FE) models are established and verified by the experimental results. The simplified FE models use beam elements (B31) and have higher calculation efficiency than the refined FE models, and are adopted for the numerical investigation of the T-ICFSTCs. Finally, based on the simplified FE model verified by the experimental results, the parametric analysis of the overall flexural stability capacity of the T-ICFSTCs under axial loads and unidirectional moments is carried out. The parameters studied include the height of the T-ICFSTCs, several geometric parameters of the cross section and the strength of material. Based on the results of numerical investigations, a preliminary design formula of the overall flexural stability capacity of the T-ICFSTCs under axial loads and unidirectional moments is proposed. This paper provides reference for engineering design of the T-ICFSTCs and the foundation to establish a complete design formula of the T-ICFSTCs under axial loads and unidirectional moments.

Collision characteristics of the intermediate coupler of a rail vehicle

Suppose the intermediate coupler of a rail vehicle is unstable during the collision process and loses its connection and energy dissipation functions. In that case, it will significantly reduce the performance of the train crashworthiness function and increase the risk of train derailment. This paper aims to establish a refined finite element model (RFEM) that can simulate the buckling behaviour and investigate the bending resistance and buckling instability characteristics of the intermediate coupler, and the accuracy of the RFEM was verified by quoting the results of an existing intermediate coupler impact test. The results demonstrated that the proposed coupler modelling method could better simulate the energy absorption characteristics and unstable behaviour. Compared to the test results, the differences in the initial crushing force, maximum longitudinal compression displacement, minimum crushing force, and maximum crushing force were 6.5%, 1.3%, 3.6%, and 6.5%, respectively. Within the allowable range of parameters, the maximum bending force linearly increased with an increase in the initial longitudinal compression displacement. As the pitch or yaw angle increased, the longitudinal buckling load of the coupler linearly decreased and became more sensitive to the pitch angle. When pitch and yaw angles existed simultaneously, the longitudinal buckling load was further reduced.

Finite Element Analysis of Precast Concrete Deck-Steel Beam-Connection Concrete (PCSC) Connectors Using Ultra-High Performance Concrete (UHPC) for the Composite Beam

A precast concrete deck-steel beam-connection concrete (PCSC) connector using ultra-high-performance concrete (UHPC) as post-cast concrete has been proposed to enable rapid on-site construction of assembled composite bridges. This paper aims to optimize the structure of PCSC connectors using the finite element (FE) model to maximize material utilization and economic efficiency. A refined FE model comprising the bond degradation at the steel–UHPC interface was developed based on the push-out experimental results of PCSC connectors. The shear mechanism of the PCSC connectors was analyzed. Subsequently, parametric analyses were performed to investigate the effects of stud diameter, height, spacing, and concrete strength on the mechanical properties of PCSC connectors. The results indicate that the bond at the steel–connection concrete interface positively affects the shear bearing capacity and stiffness of the PCSC connectors. When UHPC was used as connection concrete, it improved the bearing capacity by about 20% and the shear stiffness of the stud by about 16% compared with normal concrete, but the ductility was 38% lower. It was also found that increasing the compressive strength of the connection concrete increased the shear strength of specimens. However, when the compressive strength of UHPC exceeded 130 MPa, the additional UHPC strength did not significantly enhance the shear performance of specimens. In order to ensure the effective restraint of the connection concrete to studs, it is recommended that the minimum width and height of the connection concrete (UHPC) be determined based on the minimum horizontal spacing and height of the studs. Specifically, the length-to-diameter ratio of studs is greater than or equal to 3.18, the horizontal spacing of studs can be at least 2.82 d, and the clear distance between the outer stud shank and the edge of the UHPC cannot be less than 30 mm. The results are expected to provide a reference for the engineering design of PCSC connectors and a reference for conventional stud connectors with UHPC.

AC Loss Calculation and Analysis of Hollow Conductor for Doubly Salient Brushless DC Generator

The hollow conductor has attracted attention in variable reluctance machines (VRMs) working in harsh environment due to its good heat dissipation performance. The abundant harmonic content of the magnetic field in the slot of VRM and the complex structure of the hollow conductor make ac loss characteristics of the hollow conductor complex. Accurate and fast ac loss calculation is necessary to optimize the efficiency of VRM and provide the basis for thermal design. The doubly salient brushless dc generator (DSBLDCG), as the VRM, is analyzed in this article. First, the ac loss of the hollow conductor under a uniform alternating magnetic field is modeled numerically. The loss characteristics of hollow conductor in DSBLDCG are obtained by combining the analytical model and the simplified finite element (FE) model. Second, the refined FE model of DSBLDCG with the hollow conductor winding is established to verify the proposed method, and the influence of different structural parameters and operating conditions on the ac loss of the hollow conductor is also analyzed. Finally, the ac loss test experiment is designed for experimental verification.

Feasibility of UHPC shields in spent fuel vertical concrete cask to resist accidental drop impact

Ultra-high performance concrete (UHPC) has been widely utilized in military and civil protective structures to resist intensive loadings attributed to its excellent properties, e.g., high tensile/compressive strength, high dynamic toughness and impact resistance. At present, aiming to improve the defects of the traditional vertical concrete cask (VCC), i.e., the external storage facility of spent fuel, with normal strength concrete (NSC) shield, e.g., heavy weight and difficult to fabricate/transform, the feasibility of UHPC applied in the shield of VCC is numerically examined considering its high radiation and corrosion resistance. Firstly, the finite element (FE) analyses approach and material model parameters of NSC and UHPC are verified based on the 1/3 scaled VCC tip-over test and drop hammer test on UHPC members, respectively. Then, the refined FE model of prototypical VCC is established and utilized to examine its dynamic behaviors and damage distribution in accidental tip-over and end-drop events, in which the various influential factors, e.g., UHPC shield thickness, concrete ground thickness, and sealing methods of steel container are considered. In conclusion, by quantitatively evaluating the safety of VCC in terms of the shield damage and vibrations, it is found that adopting the 300 mm-thick UHPC shield instead of the conventional 650 mm-thick NSC shield can reduce about 1/3 of the total weight of VCC, i.e., about 50 t, and 37% floor space, as well as guarantee the structural integrity of VCC during the accidental drop simultaneously. Besides, based on the parametric analyses, the thickness of concrete ground in the VCC storage site is recommended as less than 500 mm, and the welded connection is recommended for the sealing method of steel containers.

Seismic behaviour of stainless-clad bimetallic steel welded box-section beam-columns

The stainless-clad (SC) bimetallic steel is an advanced high-performance steel with high strength and outstanding corrosion-resistant performance. It is especially competitive in the application of structures with demands of high corrosion resistance. However, the current research on SC bimetallic steels mainly focuses on the material level rather than the structural level, and it is not clear whether the excellent performance of materials can be reflected in the seismic behaviours of members. Thus, cyclic behaviours of SC bimetallic steel members need to be thoroughly investigated to fill the research gap and expand the application fields of this steel in the seismic region. To this end, this paper aims to study the cyclic behaviour of SC bimetallic steel box-section beam-columns subjected to combined constant axial load and low-cycle reciprocating lateral load through full-scale tests and finite element (FE) models. Four specimens were tested, and the influence of the width-to-thickness ratio of component plates was clarified through comparative research on the test processes, buckling details, hysteresis curves, strain curves, energy dissipation and ductility performance. Moreover, a refined FE model adopted single-layered modelling or double-layered modelling was developed respectively; and then, the model validation, the shear stress distribution at the bonding interface and parametric analyses were carried out. Research showed that the SC bimetallic steel beam-columns exhibit good energy dissipation and seismic behaviour under cyclic loadings; the smaller width-to-thickness ratio or axial load ratio could result in the plumper hysteresis curves, more sufficient energy dissipation and superior ductility performance; the ductility performance of SC bimetallic steel column was significantly improved; the ductility-based design approach proposed herein could approximately quantify the ductility performance of SC bimetallic steel box-section column, which could provide a reference for the seismic design.

Shear strength of stiffened square thin-walled concrete-filled steel tubular columns

In comparison to extensive researches on compressive or flexural behavior of stiffened square concrete-filled steel tubular (CFST) columns, few were conducted on shear behavior. The cyclic-shear behavior between stiffened and unstiffened square thin-walled CFST columns was different, and the cyclic-shear behavior of CFST columns stiffened by the diagonal ribs, which were welded on the adjacent sides of a square tube, was significantly improved, as demonstrated by recent experimental results. This work uses detailed finite element (FE) analysis and parametric analysis to explore the shear mechanism and shear contribution of each component in the stiffened CFST column. The refined FE model was developed using ABAQUS and verified by the test results of both stiffened and unstiffened CFST columns subjected to cyclic and monotonic shear loading. Based on the analysis of test results, a method based on the degree of the cross-sectional plasticity was proposed to distinguish shear failure from bending failure, as typical bending failure phenomena (concrete crushing and tube buckling) were also observed at the ends of column specimens with shear failure. Analytical results showed that the steel tube and diagonal ribs resisted the shear through shear stress, and the concrete resisted the shear through the developed compression strut confined by the horizontal stress of steel. A shear model considering the interaction between concrete and steel was then established. The mechanics-equations and regression-equations were proposed and compared with the shear test results reported in the existing literature and FE analysis. Both types of equations were found to well predict the shear strength of both stiffened and unstiffened square CFST columns.

Displacement-based blast-resistant evaluation for simply-supported RC girder bridge under below-deck explosions

An increasing trend of the intentional and accidental explosions has been threatening the safety of bridges. At present, the blast-resistant evaluation for the simply-supported RC girder bridge under below-deck explosions was conducted by numerical simulations. Firstly, by comparisons with three series of field explosion tests on the reduced-scale RC piers/columns and bridge, the adopted finite element (FE) analysis approach was validated. Then, the refined FE model of a typical two-span prototype bridge was established, and 24 explosion scenarios with three typical explosion sources specified by Federal Emergency Management Agency (FEMA) were numerically simulated. The influence of pier designs on the local damage of pier and global response of bridge was further examined, and it derives that, (i) for compact sedan and sedan bombs, increasing the concrete grades is the most feasible way and decreasing stirrup spacings are also recommended, while increasing pier diameter does not definitely enhance the blast resistance; (ii) for the cargo van bomb, the abovementioned pier designs are not effective to prevent bridge collapse. Finally, the linear relationship between the mass loss of pier and vertical displacement of bridge deck was established, and thus the traffic capacity of the post-blast bridge can be practically evaluated by analyzing a single pier instead of the whole bridge.

A Practical Bayesian Framework for Structural Model Updating and Prediction

Due to the influence of various uncertain factors, there will inevitably be certain errors between the prediction of finite-element (FE) model and observed data for a target structure. It is thus necessary to calibrate the initial FE model using the measured data to ensure the accuracy of the numerical model for the purpose of structural system identification and health monitoring. Although structural FE model updating methods have been extensively studied in the past few decades, the research based on deterministic methods in the current literature still occupies a large proportion, which cannot account for the uncertain effects during the model updating. The noise robustness of both the updating procedure and the generalization capability of the updated model are expected to be poor. The model updating based on the Bayesian theorem can quantify the uncertainty of model identification results, but it is computationally expensive for the Bayesian inference of regularization hyperparameters since the Hessian matrix is generally required to be evaluated repeatedly especially for a huge amount of uncertain model parameters. Also, effective prediction based on the refined FE model is still lacking in the literature, which is essential for judging and evaluating the quality of the updated model. This paper proposes a practical framework for structural FE model updating and prediction based on the Bayesian regularization with incomplete modal data. The structural model parameters and regularization hyperparameters are identified alternatively in an adaptive manner, and the Gauss-Newton method is used to approximate the true Hessian within the framework of the nonlinear least-squares algorithm. This is expected to improve the efficiency and robustness of model updating and prediction for handling large-scale FE models possessing a large number of uncertain model parameters. The proposed methodology is validated through the model updating and prediction conducted on a real-life pedestrian bridge based on field-testing data.

Dynamic behavior and damage assessment of RC columns subjected to lateral soft impact

In this study, the performance and damage behavior of reinforced concrete (RC) columns under lateral soft impact are comprehensively investigated using 3D finite element (FE) analysis. Firstly, refined FE models of RC columns are developed in LS-DYNA, and the corresponding simulation techniques are verified against existing experimental testing data. Then, response characteristics of a typical column under soft impact are examined, and a section damage factor is defined to quantify the damage evolution of impacted columns. After that, the effects of various design parameters, including impactor stiffness, impact elevation, axial force ratio, section dimension, and combination of impact mass and velocity, on the dynamic behavior of columns are examined. Finally, criteria for both flexural damage and shear damage are proposed based on the section damage factor, and the resistance dynamic increase factor (RDIF) of RC columns under soft impact is utilized to establish a rapid damage assessment methodology. From these results, it is proved that the dynamic responses and failure modes of RC columns under soft impact are quite different from those under hard impact. The impactor stiffness and impact elevation have a significant effect on the mechanical mechanism of columns, and the column resistance generally increases with the axial force to a certain extent. In addition, RDIF of columns decreases with the increase in the ratio of the impact time at peak force tp to the column natural period Tcol.

Seismic performance of a floating roof in an unanchored broad storage tank: Experimental tests and numerical simulations

Liquid steel storage tanks equipped with floating roofs are critical components of industrial facilities because they often store hazardous material. Major earthquakes have caused large vertical displacements of floating roofs. Consequently, roof failure and/or content loss has occurred, which has seriously endangered the surrounding environment and community. Therefore, research interest in this topic remains high, giving rise to experimental campaigns and investigatory studies concerning design and assessment approaches. The present paper aims to validate a simplified model (SM) using both a refined finite element (FE) model and experimental data. This model could later be used in the vulnerability and risk assessment framework based on numerous seismic analyses. The first part of the paper briefly introduces a shaking table test performed on a scaled steel storage tank equipped with a floating roof. This test provided useful experimental data about the vertical displacement histories of floating roofs subject to seismic loading. Subsequently, both a SM and a refined FE model aimed at simulating the shaking table test are introduced and described. Relevant experimental and numerical outcomes are then presented and discussed. Finally, in order to highlight the most relevant parameters involved, we performed a parametric study related to the SM. It is shown that both the refined FE model and the SM were capable of simulating the roof vertical displacement histories observed in the shaking table test. The former model has higher fidelity but appears to be excessively time-consuming, whilst the latter is more suitable for risk assessment purposes.

Finite element modeling of FRP retrofitted RC column against blast loading

Fiber-reinforced polymer (FRP) wrap could considerably improve the shear capacity and ductility of RC columns. FRP is therefore considered a potential material to strengthen the RC column against blast loading. Due to the high expense and safety concern of field blast tests, a very limited number of explosion tests on FRP retrofitted RC columns have been conducted, which hinders the understanding of the response of FRP retrofitted RC columns against blast loading. With advanced computational technology, it is convenient to develop a Finite Element (FE) model that can accurately capture the structural response of FRP retrofitted columns under blast loading. In this paper, a refined FE model was established to simulate the FRP retrofitted RC columns under blast loading. Strain rate effects on the concrete and steel reinforcing bar as well as the FRP composite of which the strain rate effect was commonly ignored, were all considered in the model. Comprehensive modifications were made to the Karagozian and Case concrete (KCC) model to accurately capture the mechanical properties of FRP-confined concrete. Finally, the FE model was validated with several available experimental tests. The developed FE model could capture the blast response of FRP retrofitted columns with good accuracy.

Seismic damage assessment of a supertall tubed mega frame structure based on a simplified finite element model

SummaryA tubed mega frame structure is composed of tubes located at the perimeter of the structure as mega columns and mega beams. This paper explores the applicability of this structural system to supertall buildings in high seismic intensity areas. First, a refined finite element (FE) model of a 585‐m tall tubed mega frame structure was built in ABAQUS, as well as a mega‐braced frame‐core structure on which the tubed mega frame structure is based. In order to improve the efficiency of nonlinear analyses, beam‐based simplified FE models of the two structures were developed in OpenSees and validated against the refined FE models. Then, incremental dynamic analyses of the tubed mega frame structure were conducted based on its simplified model. The damage of the tubes was quantified by a modified Park–Ang damage model. The analyses indicate that the seismic damage of the tubes in the tubed mega frame structure develops rapidly after yielding, because tubes at the perimeter of the structure suffer severe axial load under high‐intensity earthquakes. It is suggested that the axial load ratio of the tubed mega columns should be controlled to avoid brittle failure in the seismic design of supertall tubed mega frame structures.