Buildings

15 pages, 3244 KiB

Open AccessArticle

Study the Influence of Cable Breakage on Wind-Induced Vibration Characteristics of the Curved Beam Unilateral Stayed Bridge

by Shuang Zhao, Yi Shi, Jiahao Chen, Zhitao Yan, Bin Zhang, Xueqin Zhang and Zhenqiang Wang

Buildings 2023, 13(4), 1038; https://doi.org/10.3390/buildings13041038 - 14 Apr 2023

Viewed by 1161

Abstract

Existing studies have found that curved beam unilateral stayed bridges (CBUSB) have a risk of cable breakage under the design wind velocity. To ensure structural wind-induced vibration security, it is necessary to study the wind-induced vibration characteristics of CBUSBs considering the influence of [...] Read more.

Existing studies have found that curved beam unilateral stayed bridges (CBUSB) have a risk of cable breakage under the design wind velocity. To ensure structural wind-induced vibration security, it is necessary to study the wind-induced vibration characteristics of CBUSBs considering the influence of the impact load due to the cable breakage. Based on the aerodynamic coefficients determined by a wind tunnel test and the established impact load model, parametric analyses of important CBUSBs’ characteristics (beam curvature and cable arrangement scheme) and the location of the cable breakage are carried out to assess the influence of cable breakage on the time-domain statistical values and frequency-domain distribution characteristics of wind-induced vibration response. The DAF, considering the influence of cable breakages on the wind-induced vibration peak value of CBUSBs, is proposed through dynamic analysis. Study results show that, with increasing curvature, under the two-modes action of wind loads and impact loads, the fluctuation component of the CBUSB is changed, resulting in a smaller proportion of resonant response. For CBUSBs with unilateral or bilateral cable arrangements, their wind-induced vibration behavior is significantly different. The former have dynamic characteristics and the latter have quasi-static characteristics. The breakage of the shortest cable at 7/33 to 7/22 of the curved beam length and its symmetry part significantly increases the wind-induced peak response of CBUSBs. The DAF recommended values can consider the amplification effect of wind-induced vibration due to the cable breakage. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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14 pages, 4393 KiB

Open AccessArticle

Hyperbolic Paraboloid Tensile Structure—Numerical CFD Simulation of Wind Flow in RWIND Software

by Marek Kawulok, Nela Freiherrová, Marie Horňáková, David Juračka and Martin Krejsa

Buildings 2023, 13(3), 681; https://doi.org/10.3390/buildings13030681 - 04 Mar 2023

Cited by 2 | Viewed by 1168

Abstract

Tensile membrane structures combine a prestressed roofing envelope material and supporting elements. To design these structures, there is a set of recommendations in the European Design Guide for Tensile Surface Structures and some other national standards. However, currently, there is no official standard [...] Read more.

Tensile membrane structures combine a prestressed roofing envelope material and supporting elements. To design these structures, there is a set of recommendations in the European Design Guide for Tensile Surface Structures and some other national standards. However, currently, there is no official standard related to the design process of tensile structures in the European Union. The structure studied in this project is considered as permanent roofing of an external testing device in the shape of a simple hyperbolic paraboloid without enclosing walls. Snow and wind loads were analyzed as the most critical types of loading in the location. Determining the value of the snow load is relatively simple according to the European standard. However, in the case of the wind load, this shape is not considered in the European standard and needs to be solved experimentally or by numerical simulation in a wind tunnel. The present contribution focuses on numerical analysis of the wind flow in RFEM software and simulation of the wind tunnel in RWIND software. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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16 pages, 7996 KiB

Open AccessArticle

Numerical Simulation of Galloping Characteristics of Multi-Span Iced Eight-Bundle Conductors Tower Line System

by Bowen Tian, Mengqi Cai, Linshu Zhou, Hanjie Huang, Shunli Ding, Junhao Liang and Maoming Hu

Buildings 2022, 12(11), 1893; https://doi.org/10.3390/buildings12111893 - 04 Nov 2022

Cited by 1 | Viewed by 1268

Abstract

The galloping condition of an iced eight-bundle conductor tower line system, under different parameters, is studied by using a finite element model of a multi-span iced eight-bundle conductor tower line system. The galloping frequency, amplitude, traces of multi-span iced eight-bundle conductors under different [...] Read more.

The galloping condition of an iced eight-bundle conductor tower line system, under different parameters, is studied by using a finite element model of a multi-span iced eight-bundle conductor tower line system. The galloping frequency, amplitude, traces of multi-span iced eight-bundle conductors under different wind velocities, span lengths, and initial angles of wind attack are discussed. The different tower line connection methods are compared, based on existing research on the relationship between the aerodynamic characteristics of the conductor and galloping conditions. The results show that the galloping situation of a multi-span iced eight-bundle conductor tower line system varies greatly depending on the conditions, which has a significant impact on the tower line. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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Graphical abstract

24 pages, 2442 KiB

Open AccessReview

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

by Shuang Zhao, Chengtao Zhang, Xianxing Dai and Zhitao Yan

Buildings 2023, 13(8), 2033; https://doi.org/10.3390/buildings13082033 - 09 Aug 2023

Cited by 2 | Viewed by 1502

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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15 pages, 22196 KiB

Open AccessArticle

Further Explanation on the Excitation Mechanism of Stay Cable Vibration in Dry Conditions

by Duy Thao Nguyen and Duy Hung Vo

Buildings 2023, 13(6), 1543; https://doi.org/10.3390/buildings13061543 - 17 Jun 2023

Cited by 2 | Viewed by 828

Abstract

The present article outlines a research investigation carried out in a wind tunnel setting aimed at augmenting comprehension of the excitation mechanism of stay cable vibration in arid conditions. A multitude of wind tunnel experiments were thoroughly scrutinized. The study commenced by conducting [...] Read more.

The present article outlines a research investigation carried out in a wind tunnel setting aimed at augmenting comprehension of the excitation mechanism of stay cable vibration in arid conditions. A multitude of wind tunnel experiments were thoroughly scrutinized. The study commenced by conducting measurements of the stay cable vibration in conditions of steady flow. The flow angle was set at 45 degrees, and the inclination was set at 25 degrees. The wind velocities varied during the experiment. Additionally, an investigation into the flow field surrounding the stay cable’s was conducted in both vertical and horizontal directions. By utilizing two hot wire anemometers in the cable wake, an extensive database of flow field measurements was obtained. The experimental results revealed that the vibration characteristics of the stay cable under the arid conditions considered in this study aligned with findings reported in existing literature. Notably, a deeper comprehension of the excitation mechanism of a stay cable in a dry state was attained. This mechanism is closely associated with the inhibition of Karman vortices and the development of low-frequency vortices. At low wind speeds, Karman vortices predominated, resulting in small-amplitude vibrations. However, as the wind speed increased, the influence of Karman vortices diminished progressively, while the low-frequency vortices grew stronger. These low-frequency vortices exhibited high energy and a significant correlation with shedding along the stay cable, thereby inducing cable vibration in a dry environment. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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20 pages, 5215 KiB

Open AccessArticle

Wind-Induced Interference Effect of Chamfered Square Cylinders in Tandem and Side-by-Side Arrangements

by Jie Zhang, Fanghui Li, Zhibo Zhang, Te Zhang, Cheng Wang, Benjun Xiang and Yuji Zhang

Buildings 2022, 12(12), 2125; https://doi.org/10.3390/buildings12122125 - 03 Dec 2022

Cited by 2 | Viewed by 1317

Abstract

A large-eddy simulation analysis technique is introduced in this paper to determine the interference effect of chamfered square cylinders, which is crucial to predict the impact of wind pressure and load on chamfered high-rise buildings. Based on the grid convergence analysis of the [...] Read more.

A large-eddy simulation analysis technique is introduced in this paper to determine the interference effect of chamfered square cylinders, which is crucial to predict the impact of wind pressure and load on chamfered high-rise buildings. Based on the grid convergence analysis of the model and the validation of its accuracy, the aerodynamic interference effect, including the flow field distribution of parallel and tandem square cylinders with different spacing ratios has been compared and analyzed. The influence regulation and formation mechanism of the wind pressure interference effect have been explored. For side-by-side chamfered corners square cylinders, the average drag coefficient mainly shows an amplification effect, and the fluctuating lift coefficient mainly shows a reduction effect. When B/L = 1.5, the interference factor of the disturbed square cylinder reaches a maximum, which is located at the back flow field on the adjacent side. There is a clear critical spacing ratio for tandem double-cut square cylinders. When the spacing ratio exceeds the critical value, significant changes are observed in the aerodynamic performance. These include wind pressure distribution, non-Gaussian characteristics, and the interference effects of structures. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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17 pages, 6055 KiB

Open AccessEssay

Aerodynamic Characteristics Analysis of Iced Conductor Based on BP Neural Network

by Junhao Liang, Mengqi Cai, Qingyuan Wang, Linshu Zhou, Jun Liu, Guangyun Min and Hanjie Huang

Buildings 2023, 13(1), 64; https://doi.org/10.3390/buildings13010064 - 27 Dec 2022

Cited by 1 | Viewed by 1033

Abstract

Major disasters and losses would be caused by the galloping of transmission lines. The basis for studying the galloping mechanism of transmission lines is to analyze the aerodynamic characteristics of iced conductors. The wind tunnel test is a traditional way to obtain the [...] Read more.

Major disasters and losses would be caused by the galloping of transmission lines. The basis for studying the galloping mechanism of transmission lines is to analyze the aerodynamic characteristics of iced conductors. The wind tunnel test is a traditional way to obtain the aerodynamic coefficients of an iced transmission line under wind load. Due to the high cost and long duration of wind tunnel tests, an experimental method based on machine learning to predict aerodynamic coefficients is proposed. Here, the steady and unsteady aerodynamic coefficients of an iced conductor under different parameters were obtained by wind tunnel test, and then the aerodynamic coefficients of the iced conductor under different parameters were predicted by machine learning. The aerodynamic coefficients of each iced conductor varied with the angle of wind attack by the wind tunnel test. The Den Hartog and Nigol coefficients determined based on the aerodynamic coefficients obtained by machine learning and wind tunnel test are in agreement. The results show the feasibility of the machine learning prediction method. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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22 pages, 5609 KiB

Open AccessArticle

Dynamic Response Modeling of Mountain Transmission Tower-Line Coupling System under Wind–Ice Load

by Haoran Song and Yingna Li

Buildings 2023, 13(3), 828; https://doi.org/10.3390/buildings13030828 - 22 Mar 2023

Viewed by 1332

Abstract

Transmission lines have the characteristics of being tall tower structures with a large span distribution of transmission lines that are sensitive to external loads such as wind and ice, and belong to strong, nonlinear, complex, rigid-flexible coupling systems. The force process of the [...] Read more.

Transmission lines have the characteristics of being tall tower structures with a large span distribution of transmission lines that are sensitive to external loads such as wind and ice, and belong to strong, nonlinear, complex, rigid-flexible coupling systems. The force process of the tower-line structure is a combination of instantaneous and continuously stressed, so it is not accurate to judge the safety of the transmission line based only on the operation status of the transmission tower or the conductor. In this paper, a finite element model of three towers and two lines with large span and large elevation differences is established by taking into account the tower-line coupling system. From the static point of view, the static axial force of a single tower and the contribution rate of wind and ice load are analyzed, and the ultimate bearing capacity of a tension-type electric tower is obtained by considering the bending effect and critical initial defects. From the perspective of transient dynamic response, the displacement of the tower-line coupling system under wind–ice load is calculated, and the force characteristics and force transmission process of the straight tower under wind–ice load are observed. Multiple comparison models are set up to compare and analyze the sway and tension under large span and large elevation differences, and the maximum icing thickness of each group model is obtained by repeated trials. The experimental results show that under the tower-line coupling system, the contribution of wind load to the axial force of the main material is 72.92%, and the contribution of wind–ice load to the axial force of main material is 27.6

% .

The maximum increase tension under transient ice-off effect is 59.58%, the ultimate force of the tension tower is 545.5 kN, and the maximum icing thickness of the transmission line under large span and large elevation differences is 28.7 cm, which is slightly larger than the design icing thickness. In conclusion, this paper can provide reference for the construction of mountain transmission towers, power safety inspection, and line health status assessment. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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16 pages, 8630 KiB

Open AccessArticle

Experimental Study on Vortex-Induced Vibration of Steel Tubes in Transmission Towers at Various Inflow Conditions

by Zhengliang Li, Zhisong Wang, Jiahong Li and Siyuan Liu

Buildings 2023, 13(1), 252; https://doi.org/10.3390/buildings13010252 - 16 Jan 2023

Cited by 2 | Viewed by 1456

Abstract

With the extensive construction of ultra-high voltage (UHV) transmission lines, the fatigue damage of steel tube members caused by vortex-induced vibration (VIV) in tubular towers has received growing attention. Although some progress has been made in the research of the VIV of steel [...] Read more.

With the extensive construction of ultra-high voltage (UHV) transmission lines, the fatigue damage of steel tube members caused by vortex-induced vibration (VIV) in tubular towers has received growing attention. Although some progress has been made in the research of the VIV of steel tubes in uniform flow, there is still relatively scarce research on the VIV of steel tubes at various inflow conditions. In this paper, a series of wind tunnel tests are conducted to investigate the VIV of the steel tube subjected to uniform, turbulent, and oblique flows. Three turbulence intensities (I_u = 5.9%, 9.7%, and 12.6%), and four yaw angles (α = 10°, 20°, 30°, and 40°) are considered. The results show that the VIV response of the steel tube in the in-line (IL) direction is negligible compared to that in the cross-flow (CF) direction. The displacement amplitude gradually decreases as the turbulence intensity increases, accompanied by a more unstable response. For the inclined steel tube, the VIV maximum amplitude almost remains constant when α ≤ 20°, while it sharply decreased in the case of α = 30° and α = 40°. Furthermore, it was found that the so-called independent principle is applicable for α ≤ 10°. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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16 pages, 3829 KiB

Open AccessArticle

Tuned-Mass-Damper-Inerter Performance Evaluation and Optimal Design for Transmission Line under Harmonic Excitation

by Xinpeng Liu, Yingwen Yang, Yi Sun, Yongli Zhong, Lei Zhou, Siyuan Li and Chaoyue Wu

Buildings 2022, 12(4), 435; https://doi.org/10.3390/buildings12040435 - 02 Apr 2022

Cited by 7 | Viewed by 2411

Abstract

To investigate vibration control and optimal design of transmission lines with tuned-mass-damper-inerter (TMDI), the motion equation of transmission lines with TMDI is established in the paper, and the closed-form solutions of the response spectrum of transmission line displacement are derived by the frequency [...] Read more.

To investigate vibration control and optimal design of transmission lines with tuned-mass-damper-inerter (TMDI), the motion equation of transmission lines with TMDI is established in the paper, and the closed-form solutions of the response spectrum of transmission line displacement are derived by the frequency domain analysis method. The design parameters of TMDI are optimized by fixed-point theory, and the vibration control performance of TMDI is discussed. The results show that the increase in apparent mass ratio has a positive effect on the vibration control performance of TMDI; the vibration control performance is greatly affected by frequency ratio and limited by damping ratio; the increase in both mass ratio and apparent mass ratio reduces the peak values of the displacement response spectra of transmission line with TMDI; however, blindly increasing the apparent mass and mass ratio (β > 0.2 or μ > 0.4) has a limited effect on improving the vibration control performance of TMDI; compared with conventional TMD, the peak values of the controlled displacement response spectrum of the transmission line with TMDI can be reduced by about 12%, and TMDI has a better vibration suppression effect on the transmission lines. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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20 pages, 2377 KiB

Open AccessArticle

Frequency Domain Analysis of Alongwind Response and Study of Wind Loads for Transmission Tower Subjected to Downbursts

by Yongli Zhong, Shun Li, Weichen Jin, Zhitao Yan, Xinpeng Liu and Yan Li

Buildings 2022, 12(2), 148; https://doi.org/10.3390/buildings12020148 - 31 Jan 2022

Cited by 5 | Viewed by 2265

Abstract

Downburst is one of the high-intensity winds that cause transmission tower failures. The regulations of transmission tower-line systems under downburst wind loads cannot meet the design requirements at present. In this paper, the calculation formulas of the background and resonant components of transmission [...] Read more.

Downburst is one of the high-intensity winds that cause transmission tower failures. The regulations of transmission tower-line systems under downburst wind loads cannot meet the design requirements at present. In this paper, the calculation formulas of the background and resonant components of transmission tower under downburst wind loads are obtained, based on the modal analysis theory of non-stationary wind for the single-degree-of-freedom system in the frequency domain. The effects of structural dynamic characteristics, damping ratio, and mean wind speed vertical profile on dynamic effect on structural response are discussed. Then the equivalent static wind load (ESWL) is obtained according to the maximum response and compared with the finite element method (FEM) in the time domain. Applications of these formulas are addressed to the cases from the empirical model of Holmes and field record of a rear flank downdraft (RFD). The results show that the maximum responses obtained by the current formulas match well with those from the modal decomposition method and dynamic analysis with FEM. The internal forces of tower members calculated by ESWL based on maximum response are closer to the results from FEM than those calculated by downburst loads recommended in ASCE guidelines. The presented framework can be used to assist the wind-resistant design of transmission towers considering downburst wind load. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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15 pages, 4553 KiB

Open AccessArticle

Study on Wind Loads of Different Height Transmission Towers under Downbursts with Different Parameters

by Zhisong Wang, Fei Yang, Yujie Wang and Zhiyuan Fang

Buildings 2022, 12(2), 193; https://doi.org/10.3390/buildings12020193 - 08 Feb 2022

Cited by 3 | Viewed by 2524

Abstract

Disaster investigation results have shown that most wind-induced damage to transmission towers is related to downbursts. To clarify the effects of downbursts’ parameters on transmission towers with different heights, studies were conducted on five transmission towers with different diameters under static and moving [...] Read more.

Disaster investigation results have shown that most wind-induced damage to transmission towers is related to downbursts. To clarify the effects of downbursts’ parameters on transmission towers with different heights, studies were conducted on five transmission towers with different diameters under static and moving downburst wind conditions. As a comparison, the responses of the towers under normal wind conditions were studied. The results showed that the effect of downbursts on the response of the transmission tower increased with the distance between the downburst center and the tower (r) when r < 1.0 D_jet (D_jet is the jet diameter of downburst) and then decreased when r > 1.0 D_jet. The effects of jet diameter on the response of transmission towers with different tower heights were similar. As the jet diameter increased, the response of the tower continued growing until it reached a peak value and then steadily decreased soon thereafter. When the tower height was below 81.5 m, the wind load of the downburst on the transmission tower was significantly greater than that of the normal wind. As the tower height increased, the ratio of the transmission tower’s response under the two types of wind fields rapidly declined to about 0.91–1.01. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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19 pages, 9370 KiB

Open AccessArticle

Study on Wind-Induced Response of Transmission Tower-Line System under Downburst Wind

by Zhiyuan Fang, Zhisong Wang, Renyu Zhu and Hanjie Huang

Buildings 2022, 12(7), 891; https://doi.org/10.3390/buildings12070891 - 24 Jun 2022

Cited by 4 | Viewed by 2012

Abstract

Downburst is the main source of extreme wind speed in non-typhoon areas, which has caused a large amount of transmission line damage all over the world. In order to reveal the wind-induced vibration response characteristics of a transmission tower-line system under downburst, the [...] Read more.

Downburst is the main source of extreme wind speed in non-typhoon areas, which has caused a large amount of transmission line damage all over the world. In order to reveal the wind-induced vibration response characteristics of a transmission tower-line system under downburst, the nonlinear dynamic analysis of a single tower and tower-line system is carried out, and the amplification effect of tower-line coupling and fluctuating wind on the dynamic response is studied. Then, the effects of three wind field parameters closely related to the average wind profile on the wind-induced response of the tower-line system are studied. The results show that under the action of the downburst, the tower-line coupling weakens the dynamic response to a certain extent, and the dynamic amplification factor of a single tower and tower-line system is 1.1 ~ 1.3; for the self-supporting tower, when the height of the peak wind speed is close to the height of tower, the responses of the structure are more unfavorable. When the vector superposition method is used, the storm moving speed (V_t) has little effect on the wind-induced response of the tower-line system. For large-span structures such as tower-line systems, to ensure the safety of the structural design, the value of the characteristic radius (R_c) should not be too small. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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18 pages, 2637 KiB

Open AccessArticle

Optimized Design of a Tuned Mass Damper Inerter (TMDI) Applied to Circular Section Members of Transmission Towers

by Yongfei Bian, Xinpeng Liu, Yi Sun and Yongli Zhong

Buildings 2022, 12(8), 1154; https://doi.org/10.3390/buildings12081154 - 02 Aug 2022

Cited by 7 | Viewed by 1553

Abstract

Wind loads can cause significant vibrations in circular section members, resulting in serious structural hazards. In order to control the vibration of the structure and mitigate the hazards, this study investigates the optimal design and carries out a performance evaluation of a tuned [...] Read more.

Wind loads can cause significant vibrations in circular section members, resulting in serious structural hazards. In order to control the vibration of the structure and mitigate the hazards, this study investigates the optimal design and carries out a performance evaluation of a tuned mass damper inerter (TMDI) designed for the vibration control of circular section members in structures. The TMDI system is a novel vibration reduction device that utilizes an inerter based on a tuned mass damper (TMD). The main structure is a simplified Euler beam made up of circular section members, and the mass of the TMDI is coupled to the main structure by a spring and damper, as well as to the ground via an inerter. The optimization objectives are to minimize the displacement variance and maximize the energy dissipation index (EDI), and two different optimization schemes are designed. In addition to the comparative analysis of the results obtained from the different optimization schemes, a sensitivity analysis of the design parameters is also performed, and the results show that TMDI not only effectively reduces the additional mass but also has better vibration control performance and robustness than the TMD. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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16 pages, 2816 KiB

Open AccessArticle

Stochastic Buffeting Analysis of Uncertain Long-Span Bridge Deck with an Optimized Method

by Siyu Zhu, Yongle Li, Yuyun Yang and Nengpan Ju

Buildings 2022, 12(5), 632; https://doi.org/10.3390/buildings12050632 - 09 May 2022

Cited by 3 | Viewed by 1266

Abstract

The buffeting analysis of an uncertain long-span bridge deck was carried out in this paper. Due to the effect of strong spatial correlation of wind excitation, it should be assumed as partially coherent multiple excitations. The following includes a theoretical formula for the [...] Read more.

The buffeting analysis of an uncertain long-span bridge deck was carried out in this paper. Due to the effect of strong spatial correlation of wind excitation, it should be assumed as partially coherent multiple excitations. The following includes a theoretical formula for the buffeting analysis of a long-span bridge deck with uncertain parameters, which was achieved mainly by a combination of the stochastic pseudo excitation method (SPEM) and response surface method (RSM). The SPEM-RSM was firstly applied to deal with the complicated spectral density function matrix of wind excitation. The buffeting response of the bridge deck was then calculated and verified by the results from the Monte Carlo simulation (MCS). The efficiency and applicability of the hybrid method for strong spatial correlation was proved. After the comparison, the effect of uncertain structural parameters and wind speed on the buffeting performance of the bridge deck were computed. The results showed that the whole uncertainties essentially affected the buffeting response of the deck. The uncertain wind speed played the most significant role in the vertical and lateral motion of the deck. The joint influences between structural uncertainties and uncertain wind speed further affect the random characteristics of the responses. Finally, the effects of different wind speed and wind angle of attack on the aerodynamic performance of the bridge are examined. The variance of the responses increased with the development of wind speed. The effect of different attack angles on the buffeting responses was significant. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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15 pages, 2068 KiB

Open AccessArticle

Inerter Location-Based Vibration Suppression Study of a Transmission Line Equipped with Tuned-Mass-Damper-Inerter (TMDI) under Harmonic Excitation

by Xinpeng Liu, Yingwen Yang, Yi Sun, Yongli Zhong and Lei Zhou

Buildings 2022, 12(5), 657; https://doi.org/10.3390/buildings12050657 - 16 May 2022

Cited by 2 | Viewed by 1480

Abstract

This paper proposes a novel ungrounded TMDI to improve the vibration suppression performance of the transmission line under harmonic excitation. This type of inerter-based damper may transform a translational motion into a rotational motion, greatly increasing the efficiency of vibration suppression. In the [...] Read more.

This paper proposes a novel ungrounded TMDI to improve the vibration suppression performance of the transmission line under harmonic excitation. This type of inerter-based damper may transform a translational motion into a rotational motion, greatly increasing the efficiency of vibration suppression. In the present study, the differential equations of motion are first derived based on the transmission line with an ungrounded TMDI structure. Then the closed-form solution of the displacement response spectrum considering the influence of the suspension location of the inerter is developed. The impact of the inerter location on vibration suppression performance is investigated in depth by defining the suspension location factor (

υ

) and tuning the damping ratio and frequency ratio. The results demonstrate that the suspension location of the inerter has a substantial impact on the damping ratio, frequency ratio, and vibration suppression performance. When the connection location of the inerter is near to the mass of the damper, it degrades the vibration suppression performance of the system. The failure phenomenon of the inerter occurs in the range of

0.2 < υ < 0.3

, indicating that the presence of the inerter in this range does not enhance vibration suppression performance. The modal coordinate difference has a considerable impact on the vibration suppression efficacy of the TMDI. With increasing modal coordinate differences, the vibration suppression performance of the TMDI grows dramatically. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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17 pages, 13274 KiB

Open AccessArticle

Aerodynamic Forces on a Bluff Cylinder in Sinusoidal Streamwise Winds with Different Angles of Attack

by Bo Wu, Jianting Zhou, Jingzhou Xin, Hong Zhang, Liangliang Zhang and Xianyi Yang

Buildings 2022, 12(7), 1033; https://doi.org/10.3390/buildings12071033 - 17 Jul 2022

Cited by 2 | Viewed by 1229

Abstract

In the present study, multiple-fan active control wind tunnel tests are conducted to investigate the aerodynamic forces on a 5:1 rectangular cylinder in sinusoidal streamwise winds with different angles of attack (AoA). The effects of the frequency, amplitude, and AoA of the sinusoidal [...] Read more.

In the present study, multiple-fan active control wind tunnel tests are conducted to investigate the aerodynamic forces on a 5:1 rectangular cylinder in sinusoidal streamwise winds with different angles of attack (AoA). The effects of the frequency, amplitude, and AoA of the sinusoidal flow on the statistical parameters, spectral characteristics, and spanwise distributions of drag, lift, and moment coefficients are analyzed. Results show that each force has two components: the one induced by the approaching velocity oscillation and the one induced by wake vortex-shedding—this is quite different from that in the smooth flows, where the fluctuating forces are totally due to wake vortex-shedding. For each force, changes of the two components and their relationship with the frequency, amplitude, and AoA are presented. The drag fluctuations are generally dominated by the approaching velocity oscillations, whereas the lift and moment are more sensitive to wake vortex-shedding. Therefore, the drag force has better spanwise correlations than the lift and moment forces. Meanwhile, at a non-zero AoA, the inflow amplitude has different effects on the vortex-shedding-induced component as that at a zero AoA. The differences of spanwise distributions between the sinusoidal flow cases and the smooth flow cases are analyzed. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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17 pages, 10771 KiB

Open AccessArticle

Research on the Flutter Stability of Bridge Sections Based on an Empirical Formula of an Aerostatic Three-Component Coefficient

by Hui Gao, Feng Wang, Qinghai Guan, Huifang Hou and Jiawu Li

Buildings 2022, 12(8), 1212; https://doi.org/10.3390/buildings12081212 - 11 Aug 2022

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Abstract

In order to study the relationship between an aerostatic three-component coefficient (ATCC) and bridge flutter and to quickly evaluate the flutter performance of bridges, we proposed a method based on the empirical formula of the ATCC. The correlation between the flutter driving term [...] Read more.

In order to study the relationship between an aerostatic three-component coefficient (ATCC) and bridge flutter and to quickly evaluate the flutter performance of bridges, we proposed a method based on the empirical formula of the ATCC. The correlation between the flutter driving term and the critical flutter wind speed V of nine bridges (six types of girder sections) was analyzed, and its rationality was verified using wind tunnel test results. The results showed that the flutter stability of the X-term damping-driven type, i.e., the slotted box girder, was the best; the flutter stability of the X + D-term damping-driven type, i.e., the H-shape bridge deck, was the worst; the flutter stability of D-term damping-driven type was measured as being between these two values. The gray correlation analysis method was used to analyze the correlation between the ATCC and the critical flutter wind speed. As well as the relationship between the ATCC and aerodynamic damping, an empirical parameter, K, based on the ATCC, was proposed for use in determining the D-term damping-driven flutter. The flutter stability of three types of girder sections was analyzed using parameter K, and the results of the analysis were consistent with the wind tunnel test results. The results show that the ATCC obtained from the segmental model force test can be used to preliminarily realize the rapid comparison and selection of flutter aerodynamic measures for bridges. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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17 pages, 6897 KiB

Open AccessArticle

Study on Stability of Transmission Tower-Line System under a Downburst

by Yongli Zhong, Shun Li, Zhitao Yan, Xinpeng Liu, Jun Luo and Weichen Jin

Buildings 2022, 12(9), 1338; https://doi.org/10.3390/buildings12091338 - 31 Aug 2022

Cited by 2 | Viewed by 2941

Abstract

A downburst is one of the high-intensity winds that cause transmission tower failures. In recent years, downbursts have brought great disasters to the economies and lives of people all around the world. In this paper, the dynamic stability of the transmission tower-line system [...] Read more.

A downburst is one of the high-intensity winds that cause transmission tower failures. In recent years, downbursts have brought great disasters to the economies and lives of people all around the world. In this paper, the dynamic stability of the transmission tower-line system under a downburst is analyzed. The deterministic-random mixed model is used to generate the downburst wind field and ANSYS software is employed to establish the finite element model of the transmission tower-line system. The response characteristics of the transmission tower-line system in the downburst and the atmospheric boundary layer (ABL) wind fields are compared through time history analysis. The displacement response of the transmission tower is analyzed with different Z_max values and attack angles. Based on the Budiansky–Roth criterion and dynamic incremental method, the dynamic stability of the transmission tower system under the action of the downburst wind field is studied, and the corresponding wind speed conditions when the transmission tower-line system is unstable are obtained. The results show that the top displacement of the tower-line system under the action of a downburst is 1.83 times that under the ABL wind. The tower top acceleration under the downburst is 1.57 times that under ABL wind. The most unfavorable wind attack angle for a transmission tower-line system is 90°. When Z_max is within the height range of the transmission tower, the influence on the displacement of the transmission tower increases with the increase in Z_max. When Z_max exceeds the height range of the transmission tower, the influence on the displacement of the transmission tower decreases. Under the most unfavorable wind attack angle, the influence of the conductor on the stability of the transmission tower is obvious. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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16 pages, 3022 KiB

Open AccessArticle

Wind-Induced Vibration Coefficient of Landscape Tower with Curved and Twisted Columns and Spiral Beams Based on Wind Tunnel Test Data

by Shuang Zhao, Chengtao Zhang, Jiahao Yue, Zhitao Yan, Jun Liu, Bin Zhang and Bowei Liu

Buildings 2022, 12(10), 1635; https://doi.org/10.3390/buildings12101635 - 09 Oct 2022

Cited by 2 | Viewed by 1288

Abstract

The complex aerodynamic shape and structural form affect the wind-induced vibration coefficient β of landscape towers with a twisted column and spiral beam (short for LTs). To clarify the β distribution characteristics, evaluate the applicability of existing load codes, and provide accurate design [...] Read more.

The complex aerodynamic shape and structural form affect the wind-induced vibration coefficient β of landscape towers with a twisted column and spiral beam (short for LTs). To clarify the β distribution characteristics, evaluate the applicability of existing load codes, and provide accurate design wind loads, wind tunnel tests and numerical simulations were carried out on a LT. The LT’s aerodynamic coefficients and wind-induced responses were measured using rigid sectional and aeroelastic models. Furthermore, the displacement wind-induced vibration coefficient β_d and inertial load wind-induced vibration coefficient β_i(z) of the LT were calculated from these measured data. Combined with test data and a finite element model, the impacts of the wind speed spectrum type, the structural damping ratio ξ, and the peak factor g on β of the LT are analyzed. The accuracy of β of the LT calculated by Chinese and American load codes was examined and given the correction method. The results showed that the wind yaw angle had a significant impact on β_d of the LT, which cannot be neglected in current load codes. The abrupt mass increase at the platform location makes the distribution characteristics of β_i(z) of the LT different from conventional high-rise structures. The values of ξ and g have a significant impact on the calculation results of β, which are the key to the accurate design wind loads of LTs. The existing load codes are not suitable for LTs, and the correction method proposed in this paper can be used to improve them. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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16 pages, 4288 KiB

Open AccessArticle

Sectional Model Wind Tunnel Test and Research on the Wind-Induced Vibration Response of a Curved Beam Unilateral Stayed Bridge

by Shuang Zhao, Jiahao Chen, Jiahao Yue, Zhitao Yan, Jun Liu, Bin Zhang and Jianfeng Chen

Buildings 2022, 12(10), 1643; https://doi.org/10.3390/buildings12101643 - 10 Oct 2022

Cited by 2 | Viewed by 1348

Abstract

The linear curve distribution of the beam and the asymmetrical layout of the stay cables may have beneficial or adverse influences on cable-stayed bridges. Sectional model wind tunnel tests and numerical simulations were used to analyze the influence of these two factors on [...] Read more.

The linear curve distribution of the beam and the asymmetrical layout of the stay cables may have beneficial or adverse influences on cable-stayed bridges. Sectional model wind tunnel tests and numerical simulations were used to analyze the influence of these two factors on the wind-induced vibration characteristics of a curved beam unilateral stayed bridges (CBUSB) and the interaction between its stay cables and curved beams. According to the basic similarity law, the sectional models of a CBUSB example were designed and manufactured. The aerodynamic force and wind-induced vibration of the models were measured in an atmospheric boundary wind tunnel laboratory to obtain the aerodynamic coefficient and displacement, respectively. Based on the wind tunnel test results, the verified finite element model was used to determine the displacement, acceleration, and cable tension of the CBUSB excited by the buffeting force under 5 curvature cases and 4 cable layout cases. Then, band-pass filter technology and fast Fourier transform technology were used to analyze the influence of these two parameters on the wind-induced vibration characteristics of the CBUSB. Results show that the CBUSB had good aerodynamic stability in the wind tunnel at low and high wind speeds. With increasing curvature, the high-order modal vibration and modal coupling vibration of the CBUSB may be generated. The frequency, the proportion of wind-induced vibration response components, and the distribution characteristics of spectrum energy of CBUSB will be affected by 4 cable layout schemes. Cables arranged on both sides of the bridge and near the center of curvature can improve pedestrian comfort and reduce wind-induced vibration, respectively. Affected by the interaction between cable and bridge, the cable and bridge transmit their own vibration to each other, both of which contain the response components of each other. Full article

(This article belongs to the Special Issue Wind Nonlinear Analysis of Tall Buildings, High-Rise Structures, Flexible Bridges and Transmission Lines)

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