Wind-induced Structural Responses Research Articles

Wind-induced response of saddle membrane structure under typhoon wind field by weather research and forecasting model and computational fluid dynamics

Currently, the research on wind-induced response of membrane structures focuses on the normal wind field, and there is little research on typhoon with greater disaster. In this paper, the wind-induced response of saddle membrane structures under typhoon is studied by numerical simulation. Firstly, the wind field information of typhoon is simulated according to the Weather Research and Forecasting model, and the information is used as the inlet boundary condition of Computational Fluid Dynamics. The vibration modal analysis is carried out, considering the influence of wind field intensity, wind direction angle, rise-span ratio, and pretension on the displacement of the membrane. The results show that the probability density curve of wind-induced response has a certain skewness. The saddle membrane structure has the largest vibration amplitude of the membrane at 0° wind direction angle, and the most unfavorable wind pressure value of the membrane is negative. In reducing the displacement of the membrane, the effect of reducing the wind-induced vibration response by increasing the rise-span ratio of the structure is better than that of the pretension. This paper reveals that the law of wind-induced response can provide a theoretical basis for the design of membrane structures against typhoons.

Study on Wind-Induced Dynamic Response and Statistical Parameters of Skeleton Supported Saddle Membrane Structure in Arching and Vertical Direction

Wind tunnel tests and numerical simulations are the mainstream methods to study the wind-induced vibration of structures. However, few articles use statistical parameters to point out the differences and errors of these two research methods in exploring the wind-induced response of membrane structures. The displacement vibration of a saddle membrane structure under the action of wind load is studied by wind tunnel tests and numerical simulation, and statistical parameters (mean, range, skewness, and kurtosis) are introduced to analyze and compare the displacement data. The most unfavorable wind direction angle is 0° (arching direction). The error between experiment and simulation is less than 10%. The probability density curve has a good coincidence degree. Both the test and simulation show a certain skewed distribution, indicating that the wind-induced vibration of the membrane does not obey the Gaussian distribution. The displacement response obtained by the test has good stability, while the simulated displacement response has strong discreteness. The difference between the two research methods is quantitatively given by introducing statistical parameters, which is helpful to improve the shortcomings of wind tunnel tests and numerical simulations.

Wind-Induced Structural Response of Skylights: A Eurocode-Based Assessment

Wind-Induced Structural Response of Skylights: A Eurocode-Based Assessment

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.

Review of Wind-Induced Effects Estimation through Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines

The nonlinear effects exhibited by structures under the action of wind loads have gradually stepped into the vision of wind-resistant researchers. By summarizing the prominent wind-induced nonlinear problems of four types of wind-sensitive structures, namely tall buildings, high-rise structures, flexible bridges, and transmission lines, the occurrence mechanism of their nonlinear effects is revealed, providing cutting-edge research progress in theoretical studies, experimental methods and vibration control. Aerodynamic admittance provides insights into the aerodynamic nonlinearity (AN) between the wind pressure spectrum and wind speed spectrum of tall building surfaces. The equivalent nonlinear equation method is used to solve nonlinear vibration equations with generalized van-der-Pol-type aerodynamic damping terms. The elastic–plastic finite element method and multiscale modeling method are widely employed to analyze the effects of geometric nonlinearity (GN) and material nonlinearity (MN) at local nodes on the wind-induced response of latticed tall structures. The AN in blunt sections of bridges arises from the amplitude dependence of the aerodynamic derivative and the higher-order term of the self-excited force. Volterra series aerodynamic models are more suitable for the nonlinear aerodynamic modeling of bridges than the polynomial models studied more in the past. The improved Lindstedt–Poincare perturbation method, which considers the strong GN in the response of ice-covered transmission lines, offers high accuracy. The complex numerical calculations and nonlinear analyses involved in wind-induced nonlinear effects continue to consume significant computational resources and time, especially for complex wind field conditions and flexible and variable structural forms. It is necessary to further develop analytical, modeling and identification tools to facilitate the modeling of nonlinear features in the future.

Coupled numerical simulation of liquid sloshing dampers and wind–structure simulation model

Long-span bridges, high-rise buildings, chimneys, or wind turbines are often susceptible to wind-induced vibrations due to their high flexibility and lightweight. Therefore, these structures should be carefully designed to sustain the wind loads. Employing robust solutions for vibration mitigation, such as tuned liquid dampers (TLDs), enables energy dissipation at reduced structural and maintenance costs. This study presents a numerical coupling methodology for evaluating the wind-induced response of slender vertical structures that include a TLD. The methodology is based on coupling a Computational Fluid Dynamics (CFD) model of a TLD, a semi-analytical aerodynamic force model, and a structural model. The coupling is realized in a time-domain fashion by continuously exchanging sloshing forces, aerodynamic forces, and structural response. The highlight is the use of the volume of fluid (VOF) method as a CFD strategy to represent the sloshing damping forces, including an experimental validation. The methodology is applied to (i) a chimney-type structure to mitigate the buffeting and vortex-induced vibrations and (ii) a high-rise building to reduce the acceleration buffeting response for human comfort. In both cases, strategy for TLD predesign is employed based on free- and forced-vibration analysis, an equivalent tuned mass damper model, and wind vibrations, respectively. The results of the dynamic analyses show that there is a significant reduction in structural response for both cases. The outcome of this study is intended to showcase the applicability of CFD for TLD predesign and modeling nonlinear sloshing forces during dynamic analysis as an alternative to experiments. Thus, it is intended to serve academics as well as practitioners.

A comprehensive review on estimation of equivalent static wind loads on long-span roofs

Equivalent static wind load (ESWL) is helpful information for designing wind-sensitive structures since it converts complex wind-induced structural dynamic analysis into a simplified static analysis and facilitates combination of other loads or actions in structural designs. In recent years, there have been a growing number of long-span roof structures, most of which are sensitive to wind actions. Indeed, the accurate determination of ESWLs has been a primary concern in their wind-resistant design. Although some significant progress has been made on this topic, there are various issues to be addressed or improved due to a variety of reasons. With the further development of long-span roofs, there will be higher requirements for their ESWLs. This paper first combs through the existing representative methods depending on wind-induced structural responses (WISRs) and wind-induced structural stability (WISS), where the ESWLs linked with the former are the mainstream and the ones concerned with the latter are still somewhat in their initial stages of development. In each broad category, some momentous tactics of mathematics and mechanics are utilized to derive different methods. In the conclusion, this paper finally summarizes the existing achievements, highlights the technical challenges that hinder the current methods from being widely adopted and proposes some latent solutions for the future research. This review paper is anticipated to be a comprehensive reference for researchers and professionals in this field of study.

A Comparative Study of Dynamic Responses of Coastal Long-Span Bridge Under Typhoon with Different Crossing Paths

Coastal long-span bridges are intensively constructed along the western Pacific coast. While the coast is frequently disturbed by typhoons. Given that a coastal long-span bridge will experience a number of typhoons during its service life, it is important to have an understanding of the wind fields formed by typhoons with different crossing paths and corresponding structural dynamic responses. Wind and acceleration data of the Xihoumen Bridge under the influence of onshore, offshore, and landfalling typhoons were acquired by the structural health monitoring system (SHMS). Wind field features of typhoons with three types of paths were compared. The landfalling Typhoon In-fa was used to investigate the differences of wind-induced structural dynamic responses under the influence of each typhoon structural region. The covariance-driven stochastic subspace identification (SSI-COV) was used to identify the modal parameters of the bridge. The results revealed that wind field features at bridge site varied with typhoon crossing paths. The SSI-COV accurately identified the structural frequencies of first 15 vertical modes using the acceleration data under the influence of spiral rainband. The first eyewall has the most detrimental wind conditions to the bridge because the stiffening girder vibrated violently in this region.

Study on strategies for reducing training samples for accurate estimation of wind-induced structural response of LSTM networks

Long short-term memory (LSTM) neural network is an efficient method to analyze the nonlinear dynamical response of structures. However, once it is applied to a long-duration response prediction task, the demand on the computational resources will become very severe. In order to address this limitation, various strategies based on sample truncation and down-sampling were proposed in this study to reduce the sample size for predicting wind-induced structural response, i.e., to intercept representative short-duration samples from long-duration samples or down sample the long-duration sample to train the LSTM neural network. These novel strategies can achieve the goal of reducing computational burdens without loss of accuracy compared to the long-duration training samples. Based on a single-degree-of-freedom (SDOF) system, the advantages in terms of the time efficiency of the proposed methods on the training phase of LSTM neural networks have been studied, and the accuracy of the predicted wind-induced structural response was investigated. It showed that the Duhamel integral-based approach (DI-BA) of sample truncation presented the best comprehensive performance in time and accuracy. Furthermore, the DI-BA was applied to a four-degree-of-freedom (4DOF) system with different structural parameters to demonstrate its good performance in more general applications involving multiple degrees of freedom.

Influence of Friction Coefficient between Cable and Membrane on Wind-Induced Response of Air-Supported Membrane Structures with Oblique Cable Net

Cable-membrane constructions typically exhibit significant displacement and distortion under load action, and the cable-membrane contact results in relative sliding. In this paper, the interaction force between cable and membrane is transferred through frictional contact action, and as a result, the friction coefficient must be taken into consideration for the form-finding and load analysis of air-supported membrane structures. Eight kinds of P-type membrane materials commonly used in engineering were chosen, and the friction coefficients between the various membrane and cable materials were obtained. The connection between a cable and a membrane of an air-supported membrane structure is considered a contact problem, and its initial shape analysis and wind load response analysis are carried out. The influence of the friction coefficient of a cable membrane on the wind-induced response of an air-supported membrane structure is discussed, and the results are compared with those of the cable-membrane binding model under wind load.

Estimation of wind-induced response of large membrane structures with nonlinear motion-induced aerodynamic force and nonlinear geometric stiffness

Wind-induced dynamic response for large membrane structures with consideration of the coupling influences of nonlinear motion-induced aerodynamic force and nonlinear geometric stiffness is analytically evaluated in this study. By utilizing the equivalent nonlinear system approach, the Fokker-Planck-Kolmogorov equation of the membrane structures is derived, and the analytical response solutions, including probability density function, root-mean-square value, kurtosis, peak response, and peak factor, are presented. The accuracy of the proposed analytical solutions is checked by the numerical results obtained with the fourth-order Runge-Kutta approach. The findings reveal that vortex-induced vibrations occur at high wind speed regions due to the effect of nonlinear negative aerodynamic damping. Additionally, the geometric stiffness nonlinearity caused by large deformation is found to be significant for reducing the dynamic response amplitude in membrane structures. This study proposed herein presents an effective analytical approach for predicting the aero-elastic response of such flexible structures subjected to wind loads.

Two dimension-reduction probabilistic models for simulating nonstationary turbulent wind fields

The reasonable modeling of a nonstationary stochastic turbulent wind field is an important basis and premise for the analysis of the wind-induced response and reliability of engineering structures. In the present study, two dimension-reduction probabilistic models are established for simulating the multi-dimensional and multi-variable nonstationary turbulent wind fields based on the double proper orthogonal decomposition (DPOD) and the double spectral representation method (DSRM). Among them, the DPOD, originally used to simulate a stationary turbulent wind field, is extended to a nonstationary one, and the DSRM is a newly proposed method for a nonstationary turbulent wind field with a large number of simulation points. In essence, the DPOD is a discrete method with explicit physical significance and flexible spatial location of simulation points, while the DSRM is a continuous method, of which the simulation efficiency is theoretically independent of the number of simulation points. Furthermore, by introducing the dimension-reduction methods based on random function and POD-FFT (Fast Fourier transform) technique into the DPOD and the DSRM, the nonstationary stochastic turbulent wind field can be effectively described with merely three elementary random variables. Numerical examples of the nonstationary stochastic turbulent wind fields acting on a long-span bridge and a communication tower fully verify the effectiveness and superiority of the proposed methods.

Physics-informed long short-term memory networks for response prediction of a wind-excited flexible structure

Slender and flexible infrastructures such as sign supports, cantilever traffic signal structures and high mast lighting towers are sensitive to wind force and were reported to have fatigue-related issues due to the large-amplitude vibrations throughout thier life. Simulating wind-induced structural response can be an important step to evaluate their fatigue life and reliability. However, wind simulations are usually quite complicated. A comprehensive wind force model was usually developed by conducting multiple wind tunnel tests. However, due to the high cost of wind tunnel tests and the limitation of a wind tunnel, aerodynamic and aeroelastic coefficients were usually extracted only at certain wind speeds and wind directions. Interpolation or extrapolation methods were commonly used when coefficients were not available, which makes the simulation result questionable. In this study, a methodology was proposed to simulate wind-induced structural response with lower costs. The proposed method uses monitoring data in the field to develop long short-term memory (LSTM) networks. In training LSTM networks, only the monitoring data in regular wind condition was used. However, the trained LSTM network can still predict the wind-induced response in high and extreme wind conditions observed during the monitoring of the structure. The proposed method can be useful when simulating wind-induced structural response in a wide range of wind speeds and can be widely used on other structures suspected of having fatigue damage due to wind-induced vibrations.

Unified numerical model of wind-induced response of long-span structures: Aerostatic torsional divergence, flutter, and random buffeting

Wind-induced vibrations of super-long span bridges are known to be coupled, which fact is neglected in conventional calculations. In this paper, this coupling issue is tackled by a quasi-steady approach. A unified model of aerodynamic forces acting on the bridge structure is proposed. The aerostatic coefficients, transient incidence angle, fluctuating wind velocity, relative displacement and velocity of the bridge structure are used to represent the aerodynamic force acting on the deck, which allows one to avoid its conventional breakdown into random buffeting force, self-excited aerodynamic force, and aerostatic force. The proposed method is implemented in the developed software program to achieve the full process analysis of dynamic hazards, including aerostatic torsional divergence, random buffeting, and flutter divergence. Criteria for various types of hazards are then established. The feasibility and effectiveness of the proposed method and computation program are verified using the engineering examples of available long-span bridges. The results obtained show that the turbulence flow reduces the critical wind speed of torsional divergence of the structure, and changes the form of instability. Aerodynamic damping has a delay effect on this dynamic instability. Turbulent flow, aerodynamic admittance, and geometric nonlinearity are shown to have a significant impact on the flutter process. Finally, in the case of buffeting, it is proved that disregard of high-order terms of the aerodynamic force may lead to non-conservative estimations.

COMPARISON OF WIND INDUCED RESPONSE OF HIGH-RISE BUILDINGS WITH REINFORCED CONCRETE AND CROSS LAMINATED TIMBER

The main objective of this paper is to examine the wind-induced structural response of high–rise buildings constructed in the Kingdom of Saudi Arabia using reinforced concrete and lightweight cross-laminated timber (CLT) floor systems. Two major analyses were performed on two regular reinforced concrete (RC) buildings of 200 m height located in Dhahran and Jeddah. In the first instance, numerical simulations to obtain wind induced displacements and accelerations were conducted using computer software ETABS, SAP2000 and analytical model derived from building code. Then, another simulation of the building models was performed under similar wind conditions and same design criteria but by replacing the RC slabs of the buildings by cross laminated slabs. The wind data used for simulation was based on hourly wind data collection for the last 11 years (2009 – 2019). The results revealed higher story drift for both floor systems, whenever the wind speed is higher. The comparative analysis of the wind induced structural responses of traditional RC and CLT slabs showed greater accelerations at the top of the buildings with CLT floor system. However, the usage of CLT slab seems to be more feasible in the KSA considering adjusting designing lighter beam, column, and shear wall elements due to inherent CLT lightness.

Effect of time-variant structural modal parameters on accurate estimation of wind-induced dynamic responses of high-rise buildings during typhoons

Structural modal parameters of high-rise buildings during severe winds generally exhibit time-variant features, which conflicts with the assumption adopted in the wind-resistant design procedure that the modal parameters are time-invariant values. This may lead to inaccurate estimation of wind-induced structural dynamic responses, thus deteriorating the reliability of structural design of high-rise buildings. To address this issue, this paper first evaluates the time-variant modal parameters of a 600-m-high skyscraper based on building accelerations measured during Super Typhoon Mangkhut. Then, the identified time-variant modal parameters are combined with the wind loads estimated from wind tunnel test on a 1:500 scaled model of the skyscraper to reproduce the typhoon-induced building accelerations. The results show that the reproduced accelerations based on the time-variant modal parameters agree well with the field-measured ones. Moreover, a comparative study between adoption of the time-variant modal parameters and time-invariant modal parameters is conducted, which shows that the former case provides more accurate estimation of the building dynamic responses during the extreme typhoon event. This paper aims to explore an effective means for precise evaluation of typhoon-induced dynamic responses of high-rise buildings.

COMPARISON OF WIND INDUCED RESPONSE OF HIGH-RISE BUILDINGS WITH REINFORCED CONCRETE AND CROSS LAMINATED TIMBER

The main objective of this paper is to examine the wind-induced structural response of high–rise buildings constructed in the Kingdom of Saudi Arabia using reinforced concrete and lightweight cross-laminated timber (CLT) floor systems. Two major analyses were performed on two regular reinforced concrete (RC) buildings of 200 m height located in Dhahran and Jeddah. In the first instance, numerical simulations to obtain wind induced displacements and accelerations were conducted using computer software ETABS, SAP2000 and analytical model derived from building code. Then, another simulation of the building models was performed under similar wind conditions and same design criteria but by replacing the RC slabs of the buildings by cross laminated slabs. The wind data used for simulation was based on hourly wind data collection for the last 11 years (2009 – 2019). The results revealed higher story drift for both floor systems, whenever the wind speed is higher. The comparative analysis of the wind induced structural responses of traditional RC and CLT slabs showed greater accelerations at the top of the buildings with CLT floor system. However, the usage of CLT slab seems to be more feasible in the KSA considering adjusting designing lighter beam, column, and shear wall elements due to inherent CLT lightness.

Spatiotemporal variation in air density and associated effects on the wind-induced response of high-rise buildings

It is widely acknowledged that the density of the atmosphere noticeably varies with space and time. However, the effects of spatiotemporal variation in air density on the wind-induced response of building structures, especially of high-rise buildings, have usually been neglected in practice. This paper presents a field study on the spatiotemporal variation in air density based on meteorological records collected from weather stations at various latitudes and ground elevations. The vertical profile of air density in a typhoon’s core region is highlighted, and a data-driven profile model is proposed. The dependence of wind-induced response of high-rise buildings on air density is then investigated via a wind tunnel test. A pressure model for a high-rise building with a square cross-section is tested, and the wind-induced acceleration response of the building is estimated. The results suggest that if the proposed profile of the typhoon air density is adopted, the estimation of the wind-induced structural response would be below the permitted level, while if a scheme with a constant air density is adopted, the structural response would exceed the limit. This means that taking the spatiotemporal variation in air density into account in wind-resistant building design can sometimes lead to considerable economic benefits.

Research on Equivalent Static Load of High-Rise/Towering Structures Based on Wind-Induced Responses

A method of assessing equivalent static wind loads that can represent all the real ultimate states of a high-rise building and towering structure has still not been fully determined in wind engineering. Based on random vibration theory, the wind-induced response and equivalent static wind loading of high-rise buildings and towering structures are investigated using the vibration decomposition method. Firstly, the structural wind-induced mean response, background response, resonant response and background and resonant coupled response are studied in the time and frequency domains. Secondly, a new gust load factor (GLF) assessment method suitable for wind-induced displacement, bending moment and shear force response at any height of the structure is proposed, and a typical high-rise building is used as an example for comparison with the previous research results, in order to verify the effectiveness of the method in this paper. The results show the following: for high-rise buildings and towering structures, the percentage of the coupled components in the total pulsation response is less than 2%, and the influence can be ignored; the GLF based on bending moment (MGLF) and the GLF based on shear force (QGLF) increase significantly with height, and the traditional GLF methods underestimate the maximum wind effects.

Characteristics of wind loads on Twin-Tower structure in comparison with single tower

To provide a general guidance for the wind-resistant design of super-tall twin towers, a study was conducted to investigate the aerodynamic and structural dynamic characteristics of twin towers in comparison with the isolated single tower. It was found that the mutual aerodynamic interference between two towers may have a beneficial effect of disrupting the regular shedding of vortices and causing the across-wind oscillation of the twin towers appreciably smaller than that of the single tower. This beneficial effect is a function of the relative spacing between two towers and the wind direction. When the twin towers are side-by-side to wind, the beneficial effect is apparent if the relative spacing is about 1.0 or less, but it becomes negligible when the relative spacing reaches 2.0. When the twin towers are in tandem configuration to wind, the beneficial effect will remain valid until the maximum tested relative spacing of 2.0. It is also found that wind forces applied to the twin towers may contain a large proportion of out-of-phase components, which act on the two towers in opposite directions, and the corresponding structural response can be well controlled by structural links between the two towers. Therefore, the role and effectiveness of structural links in controlling wind-induced structural responses can be evaluated by the percentage of the out-of-phase components over the total wind forces, which is again a function of the relative spacing, design wind speed, wind direction of concern, and reduced building frequencies. A case study of the 570 m super-tall twin towers verified the conclusions drawn from the general study, and the use of structural links was proved to be able to reduce the design wind loads and building accelerations by more than 20%.