Wind Load Distribution Research Articles

Experimental Study on the Influence of Planar Configuration on Wind Load Distribution Characteristics of High-Rise Buildings with Whole Wind Azimuths

Experimental Study on the Influence of Planar Configuration on Wind Load Distribution Characteristics of High-Rise Buildings with Whole Wind Azimuths

Classification of equivalent static wind loads: Comparisons and applications

This paper reviews the basic ideas, developments, and codification practices of different calculation methods for equivalent static wind load (ESWL) in the past about sixty years. From the landmark work of Davenport's Gust Loading Factor (GLF), Kasperski's Load-Response-Correlation (LRC), and Katsumura, Tamura's Universal-ESWL (U-ESWL), the development thread of ESWL is clarified. The ESWLs are classified based on the number of target load effects (Single-target or Multiple-target) and on actuality (Realistic or Unrealistic). GLF is representative as a “Single-target Unrealistic” ESWL, which has been adopted in many international codes and standards for building design and is extended into many approaches considering different targets (e.g. base bending moment), and different components (along-wind, crosswind, torsional). The LRC method identifies a realistic wind load distribution that causes one target maximum/minimum load effect, is a representative of “Single-target Realistic” ESWL, is well adopted as a background component ESWL, and is further developed to consider the dynamic resonant effect. The U-ESWL simultaneously reproduces maximum/minimum load effects in multiple structural members with only two sets of load distributions, is a “Multiple-target Unrealistic” ESWL, and has also been developed and employed in a wind load code for roof structures.

Numerical Analysis of Roof Wind Pressure Distribution in Renovated Historical Buildings: Preventive Protection Measures to Mitigate Typhoon Damage

Strong winds or typhoon disasters pose significant risks to historical buildings in many countries and regions. Although numerous researchers have discussed the damage caused by natural wind disasters, little attention has been paid to the potential impact of renovation and adaptive reuse strategies on the wind resistance performance of historical buildings—an avoidable human-induced factor. This study selected the representative ancestral hall building in Guangzhou, namely Lujiang Academy, for on-site investigation and Computational Fluid Dynamics (CFD) simulation analysis. It examined two renovation approaches: installing glass curtain walls around the courtyard and enclosing the top of the courtyard with a glass canopy. This study also assessed the roof wind pressure distribution in its unaltered state to evaluate the impact of different renovation strategies on roof wind load distribution. The results showed that installing glass curtain walls can effectively reduce the upward suction effect on the main hall roof, thereby improving its wind resistance performance. Conversely, enclosing the courtyard with a glass canopy may increase negative pressure on areas such as the eaves and corridor roofs, raising the risk of roof damage. This study systematically evaluated the renovation strategies for historical buildings, detailing the specific impacts of different retrofit measures on the wind resistance performance of building roofs. The methods and findings are significant not only for the renovation of ancestral hall heritage buildings in Guangzhou but also for providing practical scientific methods and technical strategies for the conservation and renovation of similar historical structures. This research demonstrates an effective approach to enhancing wind resistance and preventive protection for historical buildings.

Numerical Investigation of Wind Flow and Speedup Effect at a Towering Peak Extending out of a Steep Mountainside: Implications for Landscape Platforms

Wind flow over complex terrain is strongly influenced by the topographical features of the region, resulting in unpredictable local wind characteristics. This paper employs numerical simulation to study the wind flow at a towering peak extending out of a steep mountainside and the wind-induced effect on onsite landscape platforms. First, the wind flow from seven different directions is explored via 3D numerical simulations, and the wind load distribution on the platforms is highlighted. Second, a 2D numerical simulation is conducted to evaluate the wind speedup effect at the side peak, examining the influence of the side peak height and the mountainside steepness on the wind speedup factor. The numerical simulations presented in this research were validated by replicating a published numerical and experimental study. The results illustrate the amplifying and blocking effects of the surrounding topography, yielding unpredictable and nonuniform wind pressure distribution on the platforms. The presence of the side peak leads to a significant increase in the speedup factor, and the side peak height and the mountainside steepness have a moderate influence on the value of the speedup factor. Additionally, the speedup factor obtained from this study varies significantly, especially near the surface, from the recommendations of several wind load standards. Consequently, the impact of the local terrain and the wind speedup effect must be thoroughly assessed to ensure the structural integrity of structures installed at a similar topography.

Wind Load Distribution in Float Photovoltaic System

This paper investigates wind load distribution in float PV plants. Wave and wind load are dominant environmental load factors in determining design load in float PV plants. In particular, wind load is determined based on the numerical analysis results. The literature indicates that several input parameters exist, such as inlet angle and space between PV modules. An exemplary structure with ten arrays of PV modules was generated in this study. To investigate the wind load distribution in a float PV plant, the computational fluid dynamic (CFD) analysis was conducted with variables including wind direction (inlet angles) and three wind speeds (36.2, 51.7, and 70 m/s) in PV modules in the floating structure. Based on the numerical analysis, the wind load distribution of PV modules can be characterized with respect to the inlet angle and wind speed. The numerical results show that the wind loads in the central arrays are dominant.

CFD wind tunnel investigation for wind loads of steel television tower with grid structure

Television(TV) towers with grid structures serve as broadcasting frequency modulation or television transmission signals and provide sightseeing opportunities. Accurate wind load information is critical to the design of these towers to ensure their resistance to wind. Due to the scaling ratio of the test model, wind tunnel test can only determine the overall wind load, resulting in the loss of wind load information on specific rods. However, there is currently a lack of research on the wind loads of the specific rods of a core tube with a grid structure. This article focuses on this special topic. Computational fluid dynamics (CFD) technology, which was validated based on the Commonwealth Advisory Aeronautical Research Council (CAARC) model, was employed in simulation for a towering television tower with a grid structure. Wind load distributions of the grid structure and core tube were studied, including flow streamlines, velocity profiles and wind pressure distributions. The results indicate that the wind pressure distribution on the outer surface of the cross rods is similar at different heights. Net wind pressures of the rods in the flow separation zone are close to 0, which significantly reduces the across-wind load. Different wind direction angles significantly influence the wind load of the grid structure but slightly influence the core tube. The simulation results can provide a reference for wind load design of similar grid structures.

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.

Large Telescope Wind Load Estimation with Gradient Segments Superposition and its Servo Control

Obtaining the wind load distribution on the telescope aperture is very important to estimate its influence and reduce the wind disturbance on the telescope system. The aperture of the radio telescope structure can be as large as 100 m and therefore, the uniform wind load on the aperture assumption is not suitable for the radio telescope with large aperture. In this paper, a gradient segments superposition method for calculating the wind load has been proposed. The proposed method has been constructed by combining two regional divisions. First, reflecting surface has been evenly divided in the altitudinal direction. Second, the reflecting surface has been divided into several uniform rings assuming that the wind load coefficient on different rings are different. For the 110 m aperture radio telescope, the wind load estimation results differ by 28%. After that, a structural dynamics model of telescope has been established and a fuzzy PID controller has been designed to reduce wind disturbance. The Root Mean Square Error of telescope pointing under wind disturbance has been reduced by 67.8%. It is suggested that the proposed wind load estimation method has lay a solid foundation for the design of the large telescope system under wind disturbance.

Experimental Study of Wind Loads on Tubular Crossarms of Transmission Towers

The actions exerted by yawed wind on the crossarm substantially differ from those on the tower body due to the presence of the angle between the crossarm’s cross-section and the incoming flow, and this phenomenon deserves a better understanding. Focusing on the tubular crossarms with round-section members, this paper aims to determine insights into wind actions, as affected by various factors, such as the tower type, the mean width to mean height ratio, the solidity ratio, and the wind incidence angle, and thereby derive the wind loads for design. Accordingly, a succession of wind tunnel tests was conducted by using quadrilateral and triangular crossarm models with various solidity ratios and mean width to mean height ratios. The method of direct force measurement (DFM) is employed for the high frequency force balance (HFFB) test to attain the transverse and longitudinal forces on the crossarm simultaneously. It was found that the wind load coefficients increase with increases of the mean width to mean height ratio and decreases of the solidity ratio. Moreover, in the case of the incoming flow perpendicular to the crossarm face, it is concluded that compared to the quadrilateral crossarm, the triangular crossarm possesses a relatively smaller drag coefficient, provided a moderate mean width to mean height ratio of 1.19. Furthermore, an analysis of the experimental results shows that the skewed wind load factor specified in the relevant codes would overestimate the effects of the wind incidence angle and the variations in mean width to mean height ratio, which is evident in the tests but not considered in the codes. It is worth noting that the experimental results show that the crosswind force is pronounced, which is usually ignored in the skewed wind load factor-based approach. Comparatively, using wind load distribution factors seems to be more rational. Thus, the corresponding estimating equations are proposed for the wind load-distribution factors of the crossarms, which agree well with the experimental results. The developed equations would greatly facilitate the determination of wind loads on tubular crossarms.

Wind-Induced Responses and Wind Loads on a Super High-Rise Building with Various Cross-Sections and High Side Ratio—A Case Study

With the development of construction technology and material, more and more super high-rise buildings will be constructed in the future. In a specific metropolitan area, super high-rise building with various cross-section and high side ratio have to been designed and constructed due to the size limitation of construction site. This kind of building is also very prone to wind excitations. In this research, wind tunnel tests for a practical case of this kind of building with surrounding buildings were carried out in atmospheric boundary wind tunnel. Equivalent static wind loads (ESWLs), wind-induced responses and wind load distribution on the building were analyzed. In particular, the base overturning moment along the axis with weak lateral stiffness were investigated for bearing capacity limit state design of the building. The results demonstrate that the maximum value of wind-induced base overturning moments and acceleration responses appears at 60° or 330° wind directions instead of the orthogonal wind direction, and the aerodynamic interference of surrounding buildings affects the wind pressure distribution on facades of the building. These results and conclusion may be helpful to wind-resistant design of super high-rise buildings with high side ratio.

Simulation-driven Wind Load Analysis and Prediction for Large Steerable Radio Telescopes

Large steerable radio telescopes can rotate in azimuth and elevation, with various upwind postures and complex wind load characteristics. In order to 5 Corresponding authors obtain the wind load distribution on the reflector and the wind force coefficients in different upwind postures, this work took the reflector of the QiTai Telescope in Xinjiang as the object. The wind pressure distribution, drag coefficient, side force coefficient, lift coefficient, and total force coefficient of 361 groups of reflectors with different upwind postures were calculated and analyzed by a numerical simulation method. The results show that the force on the reflector when the concave surface faces the wind is significantly greater than when the convex surface faces the wind. The surrogate models for calculating wind force coefficients were established based on the polynomial response surface model (PRSM) and regularized minimum-energy tensor-product spline (RMTS). The adjusted R-squared of RMTS is 0.98, and the root mean square error is below 0.1, which proves RMTS is significantly better than PRSM. Compared with the numerical simulation values, the absolute errors of the drag coefficient, side force coefficient, lift coefficient, and total force coefficient of the reflector with azimuth and elevation of 45° predicted by RMTS are 0.02, 0.027, 0.032, and 0.046, respectively. The relative errors are 2.42%, 2.76%, 2.23%, and 2.43% , respectively. It is proved that the RMTS surrogate model is reliable and that the predicted data can fast provide sufficient information for the wind-resistant design of the large steerable radio telescopes.

Variation of wind load distribution on gable roof building

Wind forces and their impact on the structural integrity of roofs and walls are pivotal considerations in architectural and engineering design. This study discusses the effect of wind load on gable roof buildings with varying slopes. Gable roof structures find extensive application in industrial construction projects. Based on wind tunnels with rigid models, wind pressure distributions on gable roof buildings with different aspect ratios were measured simultaneously. Special attention is required for the safe design of the building. Information regarding the wind pressure coefficients on buildings is available in codes of practices of various countries dealing with wind loads; however, such information is very limited. The present study will examine the suitability of four building models with roof angles of 10º, 15º, 20º, and 25º and will be analyzed using IS 875 (Part 3), and various forces will be calculated. Then, the same buildings will be modeled using STAADPro/SAP2000, and the comparison of the analysis will be made. Further, a building situated at various slopes on a hill will be modeled using STAAD-Pro/SAP2000, and the variation of Wind Forces along the slope will be studied. The expected results of this study will be finding out the most critical slope of a gable roof on a building and reducing the effect of wind forces on it. Furthermore, the most savior location of a building along the hill slope will be investigated, and the ways to reduce the effect of these wind forces will be studied.

An effective two-stage optimization method on aerodynamic measures to mitigate wind loads considering uncertainties in wind direction and velocity

At present, deterministic optimization methods on aerodynamic measures are usually employed to mitigate wind loads at one certain wind direction, ignoring the effects of the uncertainties in wind direction and velocity on wind loads. The uncertain optimization method with the consideration of the joint probability distribution (JPD) of wind speed and direction is hardly to conduct because it is very time-consuming and costly. In order to overcome these shortcomings, this study proposes an effective two-stage uncertain optimization method considering uncertainties in wind direction and velocity to achieve a considerable reduction of wind loads. In the first stage, the exceedance probability distribution of wind loads is determined based on the JPD and the wind load coefficients on the building, and the wind loads in the most unfavorable range of wind directions are chosen as the optimization objective. In the second stage, the optimal values of the design variables are determined by an interval optimization algorithm using the surrogate model and non-dominated sorting genetic algorithm II in the most unfavorable range of wind directions, where the surrogate model is constructed by the radial basis function method to relate the wind load coefficients to the design variables of aerodynamic measures, and can significantly improve the efficiency of the optimization algorithm. To validate the effectiveness of the proposed method, a flat-roof building with four spoilers is investigated and the rotation angles of spoilers are set as the design variables. The results show that the proposed method reduces the uplift wind loads with a 50-years return period up to 15.48% compared to the deterministic optimization method for one certain wind direction.

Evaluation of wind loads on square transmission towers with angle members under skewed winds

In the current wind loading codes for transmission towers, the wind loads under skewed winds are characterized by the global drag coefficient, skewed wind load factor, and wind load distribution factor. The recommended global drag coefficients in the codes borrowed from the lattice frames and trusses show discrepancy with the wind tunnel test. The skewed wind load factor reflecting the amplification of wind loads at skewed directions is demonstrated to vary with the tower geometry, which is not factored in the codes. In addition, the wind load distribution factor in the codes is determined by assuming that the wind load direction is the same as the wind direction, whose rationality needs to be examined. In this paper, a series of wind tunnel tests on the body, cross-arm and head sections of the widely used square angle-steel transmission towers are performed under multi-directional winds. Based on wind tunnel tests, the three coefficients and factors in the codes are extensively examined, and new formulas for them are calibrated. The results of this study could provide more accurate estimate of wind loads on the transmission towers.

풍력 발전과 부하 사이의 상관성을 고려한 확률론적 전력 조류 해석 기법 제안

Due to the increase of the renewable energy and variation of the distributed sources, the power system experience more variability and uncertainty than before. In this paper, we propose an framework for steady-state analysis of power systems using the joint probabilistic information about the wind speeds and loads. Vine copula is employed to capture the the complex dependencies between wind speeds and loads in the multiple regions. In addition, we investigate probabilistic modeling based on the parametric estimation and Wasserstein distance to depict the marginal distribution of wind speed and load. The effectiveness of the proposed method was tested on an IEEE 39-bus system using Python and MATLAB. From the simulation, it was found that the probabilistic power flow method (PPF) that combined vine copula sampling outperforms the deterministic approach and the PPF with random simple sampling in terms of the quantitative risk assessment in the power system.

AIRFLOW SIMULATION AT THE UKRAINIAN ANTARCTIC STATION

The location of the Ukrainian Antarctic Akademik Vernadsky station leads to several problems related to the need to ensure the livelihood and safety of people. The infrastructure of Vernadsky station is affected by significant climatic loads during the year, such as wind, rain, snow and low temperatures. The destruction or even significant damage to the infrastructure of the Antarctic station can endanger the lives of people who are on it due to the inability to evacuate. The purpose of the study is to determine the fields of wind load distribution within the Antarctic Vernadsky station. This is necessary in order to identify the infrastructure objects that are most affected by wind loads. SolidWorks computer-aided design software environment allows you to build geometric models of objects of varying complexity. That is why this system was chosen to model the infrastructure of the Ukrainian Antarctic Vernadsky station. Simulation modeling of wind load was performed in the computer-aided engineering software of finite element analysis ANSYS. Geometric models of the infrastructure objects of the Ukrainian Antarctic Vernadsky station were created. Simulation modeling of the station under wind load conditions was performed. It is shown that in the case of wind from the mainland, the elements of the station's infrastructure that receive the main wind load are the main building and the VST-200. It is determined that the presence of a pile foundation affects the velocity vector fields, so this element should not be neglected when performing further research. It is shown that practically all objects of the station's infrastructure lead to significant turbulent vortices. Geometric models of the infrastructure objects of the Ukrainian Antarctic station Academician Vernadsky were created. Simulation modeling of the station under wind load conditions was performed. It is shown that in the case of wind from the mainland, the elements of the station's infrastructure that receive the main wind load are the main building and the RVS-200. It is determined that the presence of a pile foundation affects the velocity vector fields, so this element should not be neglected when performing further research. It is shown that almost all infrastructure objects of the station lead to significant turbulent tails when they flow around.

Wind-Induced Interference of a Rectangular-Section Building on the Dome-Roof

There are no specific regulations regarding the interference effects that an adjacent building can place on the wind load distribution of a dome roof structure. Furthermore, the influence between an adjacent rectangular-section building and the dome roof structure on the wind-induced interference is not well understood yet. Thus, in this paper, computational fluid dynamics (CFD) is used to simulate the mean wind pressure of the dome roof structure after interference by a rectangular-section building facing the dome. The accuracy of numerical results is verified through a wind tunnel test. The effects of different building heights or widths as well as distances between the interference building and the dome on the interference are analyzed. Different wind directions in intervals of 15∘are examined in the analysis to identify the worst wind direction. The results reveal that the passage effect caused by the interference is the main reason for the increase of suction on the roof, and the height ratio has the greatest influence on the passage effect. The region of the roof nearest to the interference building experiences the greatest suction considering all wind directions, and the side regions of the roof are relatively safe in most cases. The results of this paper can provide a reference for engineers tasked with wind-resistant design of long-span dome structures.

Numerical Simulation of Wind-induced Swing Angle of 1000kV Transmission Line Suspension Insulator Strings Considering Dynamic Response

The wind-induced swing angle of insulator strings directly affects the electrical insulation performance and the construction cost of the UHV transmission project. However, due to not considering the fluctuating wind pressure, the calculation results of wind-induced swing tend to be conservative when adopting the recommended guidelines of standard especially in the face of severe weather. This paper simulates the transient wind field of strong winds based on time-space correlation characteristics and constructs the fluctuating wind load distribution model exerting on the UHV transmission line. Then a refined finite element model of the multi-span transmission line including the entire tensile section is established. And the swing angle of the insulator strings calculation formula is fitted based on the calculation results of the wind-induced swing response. The calculation result shows the swing angle decreases with the increase of ice thickness, and the magnified coefficient of the wind-induced swing angle at the target tower under the basic wind speed of 15m/s is 1.03.

Influence of Refined Wind Load Parameters and Wind-Loading Mode on Wind-Induced Responses of a Long Cross-Arm Angle-Steel Transmission Tower

This study aims to investigate refined wind load parameters on main rods and the influence of wind-loading mode on wind-induced responses of the angle-steel transmission tower. The wind load parameters discussed in this study include drag coefficients, wind load distribution factors and skewed wind load factors. To achieve the aim, wind tunnel tests were conducted to explore aerodynamic loads for integrated frame, single frame, and main rod models of cross-arm and tower body. The wind load parameters of the different models were investigated. In addition, a series of wind-induced vibration simulation was applied to examine the wind-induced responses of an ultra-high voltage (UHV) transmission tower with a long cross-arm under concentrated and distributed wind loads. The simulated results under the two types of wind loads were compared. The results show that the longitudinal drag coefficients of the main rods are smaller than the values of the integrated frame, and equivalent on average to the values of the single frame. The experimental shielding factor of the cross-arm is larger than those in different standards due to the joint drag effects of leeward, upper, and lower faces of the cross-arm in the wind tunnel test. The experimented shielding factor of the tower body is in line with those referring to the Chinese and AS/NZS standards, and slightly larger than those based on the British and JEC standards. The skewed wind load factors of the main rod models are quite different from other models for cross-arm and tower body. The wind-induced vibration simulation suggests that, the wind-loading mode has limited impact on the displacements, accelerations, and gust factors of the transmission tower, but significantly influences the maximum normal stresses (MNSs) of the rods’ cross-sections. The MNSs caused by the distributed wind loads are obviously greater than those caused by concentrated wind loads, especially for the rods at the two ends of the cross-arm.

Investigation on aerodynamic characteristics for steel tubular cross-arms of transmission tower under skew wind

A study of the aerodynamic characteristics of steel tubular butterfly-shaped cross-arms in a transmission tower head under skew wind is presented. A wind tunnel test was conducted under skew wind by using a scaling model, and a numerical simulation was performed with a high-precision three-dimensional tower head model. The drag coefficient, skew wind load factor, and wind load distribution factor of the cross-arms obtained from the experiment and numerical simulation were identified and compared with those acquired from different codes. It is concluded that the indirect force measurement method was found to underestimate aerodynamic forces acting on windward cross-arms. For single cross-arm, the horizontal cross-arm showed stronger shielding effect than the inclined cross-arm. A fitting formula for the skew wind load factor of the cross-arm is proposed, and values obtained from it matched experimental and simulation data well. A comparison between calculated and measured wind load distribution factors showed that although longitudinal load distribution factors calculated with the Chinese standard (2018) were consistent with measured data, calculated transverse load distribution factors did not match measurements well. It is suggested that the effect of the transverse lift wind force should be considered in the calculation of wind load distribution factors.