scholarly journals Estimation Formula of Modal Frequency of High-Rise Buildings under Different Wind Speeds during Typhoons

2021 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Jiaxing Hu ◽  
Zhengnong Li ◽  
Zhefei Zhao
Keyword(s):  
Monitoring System ◽  
Coherence Function ◽  
Time History ◽  
Spectral Density Function ◽  
Wind Speeds ◽  
High Rise ◽  
Fundamental Frequencies ◽  
Estimation Formula ◽  
Mean Wind Speed ◽  
Wind Characteristics

On 18 October 2016, the wind-induced effects of a high-rise building with square section was measured by the monitoring system in Haikou of China during Typhoon Sarika. The wind characteristics atop the building and the time-history responses of the translational and rotational accelerations on different floors were measured by the monitoring system; the first three modal parameters were identified according to the measured acceleration. The results show that the combinations of the cross spectral density function, phase spectrum, and coherence function can clearly judge the phase of the measured floors in the frequency resonance area as well as its modal frequencies at the first three orders. The modal frequencies at the first three orders decrease linearly with the growth of mean wind speed within the range of 0~20m/s. The estimation formula of the modal frequencies of high-rise buildings considering the influences of different wind speeds is put forward, which is expected to fill the gap in the existing specification for the quantitative analysis of the influences of wind-loads on the fundamental frequencies of high-rise buildings.

Wind tunnel tests on the characteristics of wind fields over a simplified gorge

2016 ◽  
Vol 20 (10) ◽  
pp. 1599-1611 ◽  
Author(s):  
Peng Hu ◽  
Yongle Li ◽  
Yan Han ◽  
CS Cai ◽  
Guoji Xu
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Direction ◽  
Wind Field ◽  
Small Range ◽  
Wind Fields ◽  
Wind Speeds ◽  
Mean Wind Speed ◽  
Wind Characteristics ◽  
The Mean

Characteristics of wind fields over the gorge or valley terrains are becoming more and more important to the structural wind engineering. However, the studies on this topic are very limited. To obtain the fundamental characteristics information about the wind fields over a typical gorge terrain, a V-shaped simplified gorge, which was abstracted from some real deep-cutting gorges where long-span bridges usually straddle, was introduced in the present wind tunnel studies. Then, the wind characteristics including the mean wind speed, turbulence intensity, integral length scale, and the wind power spectrum over the simplified gorge were studied in a simulated atmospheric boundary layer. Furthermore, the effects of the oncoming wind field type and oncoming wind direction on these wind characteristics were also investigated. The results show that compared with the oncoming wind, the wind speeds at the gorge center become larger, but the turbulence intensities and the longitudinal integral length scales become smaller. Generally, the wind fields over the gorge terrain can be approximately divided into two layers, that is, the gorge inner layer and the gorge outer layer. The different oncoming wind field types have remarkable effects on the mean wind speed ratios near the ground. When the angle between the oncoming wind and the axis of the gorge is in a certain small range, such as smaller than 10°, the wind fields are very close to those associated with the wind direction of 0°. However, when the angle is in a larger range, such as larger than 20°, the wind fields in the gorge will significantly change. The research conclusions can provide some references for civil engineering practices regarding the characteristics of wind fields over the real gorge terrains.

scholarly journals Evaluation of wind characteristics in Bac Lieu in 2016 using the weibull function

2017 ◽  
Vol 17 (4B) ◽  
pp. 37-43
Author(s):  
Pham Xuan Thanh ◽  
Nguyen Xuan Anh ◽  
Le Van Luu ◽  
Hiep Van Nguyen ◽  
Hoang Hai Son ◽  
...  
Keyword(s):  
Wind Speed ◽  
Shape Factor ◽  
Maximum Energy ◽  
Weibull Function ◽  
Data Set ◽  
Wind Speeds ◽  
Mean Wind Speed ◽  
Wind Characteristics ◽  
Two Parameters ◽  
Factor C

In this paper, the characteristics of wind speed at 20 m height at the Bac Lieu atmospheric physic station (Bac Lieu station) in 2016 were evaluated using the Weibull distribution function. The wind speed data set (every minute) from January 7th  to December 31st, 2016 was used to calculate the two parameters of  Weibull function including Weibull shape factor “k” and Weibull scale factor “c”. The results showed that at the Bac Lieu station in 2016, the values of k and c were 1.69 and 3.91, respectively. Some characteristics of wind speed were also estimated such as wind energy density (Pa/A=57.3 W/m2), wind speed of maximum energy carrier (Vmec=6.2 m/s), the most probable wind speed (Vmp=2.3 m/s), mean wind speed (Vmean­=3.5 m/s)  and standard deviation of wind speeds (s = 2.1 m/s).

scholarly journals Study on Typhoon Characteristic Based on Bridge Health Monitoring System

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Xu Wang ◽  
Bin Chen ◽  
Dezhang Sun ◽  
Yinqiang Wu
Keyword(s):  
Wind Speed ◽  
Monitoring System ◽  
Wind Velocity ◽  
Gaussian Distribution ◽  
Full Range ◽  
Integral Scale ◽  
Gust Factor ◽  
Wind Speeds ◽  
Bridge Health Monitoring ◽  
Mean Wind Speed

Through the wind velocity and direction monitoring system installed on Jiubao Bridge of Qiantang River, Hangzhou city, Zhejiang province, China, a full range of wind velocity and direction data was collected during typhoon HAIKUI in 2012. Based on these data, it was found that, at higher observed elevation, turbulence intensity is lower, and the variation tendency of longitudinal and lateral turbulence intensities with mean wind speeds is basically the same. Gust factor goes higher with increasing mean wind speed, and the change rate obviously decreases as wind speed goes down and an inconspicuous increase occurs when wind speed is high. The change of peak factor is inconspicuous with increasing time and mean wind speed. The probability density function (PDF) of fluctuating wind speed follows Gaussian distribution. Turbulence integral scale increases with mean wind speed, and its PDF does not follow Gaussian distribution. The power spectrum of observation fluctuating velocity is in accordance with Von Karman spectrum.

Static and Dynamic Analysis for Tower in a High-Rise Steel Reinforced Concrete Composite Structure

2013 ◽  
Vol 788 ◽  
pp. 558-561
Author(s):  
Jian Qiang Wang ◽  
Wen Tao Ma ◽  
Min Jing Ma
Keyword(s):  
Reinforced Concrete ◽  
Composite Structure ◽  
Linear Time ◽  
Response Spectrum ◽  
Time History ◽  
Vibration Period ◽  
Small Earthquake ◽  
Steel Reinforced Concrete ◽  
Static And Dynamic Analysis ◽  
High Rise

Steel reinforced concrete composite structure which apply in the high-rise buildings, not only save steel, but also have excellent properties in fire prevention, anti-corrosion, and seismic performance, and improve the speed of construction, economic efficiency.This thesis based on the analyse of a steel reinforced concrete composite structure tower and the domestic and foreign experts study use Finite Element Analysis software SAP2000 analyze the dynamic Performance of the structure to draw the inherent vibration period and frequency of the structure. The structure is analyzed to obtain its deformation with different height of the structural elements under a small earthquake. Structure and component in elastic stage when suffur a small earthquake. Using the mode decomposition response spectrum method and method of linear time history analysis, the maximum horizontal displacements of the structural layer, the maximum inter-story displacement and the maximum inter-story displacement angle is obtained to see if the results within a predetermined range.

scholarly journals Wind Power potential in Kigali and Western provinces of Rwanda

2015 ◽  
Vol 2 (1) ◽  
pp. 25-36
Author(s):  
Otieno Fredrick Onyango ◽  
Sibomana Gaston ◽  
Elie Kabende ◽  
Felix Nkunda ◽  
Jared Hera Ndeda
Keyword(s):  
Wind Speed ◽  
Probability Density ◽  
Wind Power ◽  
Wind Direction ◽  
Small Scale ◽  
Energy Potential ◽  
Wind Speeds ◽  
Mean Wind Speed ◽  
Wind Energy Potential ◽  
Low Wind Speeds

Wind speed and wind direction are the most important characteristics for assessing wind energy potential of a location using suitable probability density functions. In this investigation, a hybrid-Weibull probability density function was used to analyze data from Kigali, Gisenyi, and Kamembe stations. Kigali is located in the Eastern side of Rwanda while Gisenyi and Kamembe are to the West. On-site hourly wind speed and wind direction data for the year 2007 were analyzed using Matlab programmes. The annual mean wind speed for Kigali, Gisenyi, and Kamembe sites were determined as 2.36m/s, 2.95m/s and 2.97m/s respectively, while corresponding dominant wind directions for the stations were ,  and  respectively. The annual wind power density of Kigali was found to be  while the power densities for Gisenyi and Kamembe were determined as and . It is clear, the investigated regions are dominated by low wind speeds thus are suitable for small-scale wind power generation especially at Kamembe site.

scholarly journals Wind speed modeling based on measurement data to predict future wind speed with modified Rayleigh model

2021 ◽  
Vol 12 (3) ◽  
pp. 1823
Author(s):  
Suwarno Suwarno ◽  
Rohana Rohana
Keyword(s):  
Wind Speed ◽  
Measurement Data ◽  
Rayleigh Distribution ◽  
Scale Factor ◽  
Percentage Error ◽  
Monthly Data ◽  
Wind Speeds ◽  
Wind Characteristics ◽  
One Year ◽  
The Many

The development of modeling wind speed plays a very important in helping to obtain the actual wind speed data for the benefit of the power plant planning in the future. The wind speed in this paper is obtained from a PCE-FWS 20 type measuring instrument with a duration of 30 minutes which is accumulated into monthly data for one year (2019). Despite the many wind speed modeling that has been done by researchers. Modeling wind speeds proposed in this study were obtained from the modified Rayleigh distribution. In this study, the Rayleigh scale factor (<em>C<sub>r</sub></em>) and modified Rayleigh scale factor (<em>C<sub>m</sub></em>) were calculated. The observed wind speed is compared with the predicted wind characteristics. The data fit test used correlation coefficient (R<sup>2</sup>), root means square error (RMSE), and mean absolute percentage error (MAPE). The results of the proposed modified Rayleigh model provide very good results for users.

scholarly journals Graz Lagrangian Model (GRAL) for Pollutants Tracking and Estimating Sources Partial Contributions to Atmospheric Pollution in Highly Urbanized Areas

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1375
Author(s):  
Aleksey A. Romanov ◽  
Boris A. Gusev ◽  
Egor V. Leonenko ◽  
Anastasia N. Tamarovskaya ◽  
Alexander S. Vasiliev ◽  
...  
Keyword(s):  
Air Quality ◽  
Urban Landscape ◽  
Weather Conditions ◽  
Lagrangian Model ◽  
Emission Sources ◽  
Computational Domain ◽  
Surface Atmospheric Layer ◽  
Wind Speeds ◽  
High Rise ◽  
Heterogeneous Landscape

Computational modeling allows studying the air quality problems in depth and provides the best solution reducing the population risks. This research demonstrates the Graz Lagrangian model effectiveness for assessing emission sources contributions to the air pollution: particles tracking and accumulation estimate. The article describes model setting up parameters and datasets preparation for the analysis. The experiment simulated the dispersion from the main groups of emission sources for real weather conditions during 96 h of December 2018, when significant excess of NO2, CO, SO2, PM10, and benzo(a)pyrene concentrations were observed in the Krasnoyarsk surface atmospheric layer. The computational domain was a parallelepiped of 40 × 30 × 2.5 km, which was located deep inside the Eurasian continent on a heterogeneous landscape exaggerated by high-rise buildings, with various pollutions sources and the ice-free Yenisei River. The results demonstrated an excellent applicability of the Lagrange model for hourly tracking of particle trajectories, taking into account the urban landscape. For values <1 MPC (maximum permissible concentration) of peak pollutants concentrations, the coincidences were 93 cases, and for values < 0.1 shares of MPC, there were 36 cases out of the total number of 97. The same was found for the average daily concentration for values <1 MPC—31, and for values <0.1 MPC—5 matches out of 44. Wind speeds COR—65.3%, wind directions COR—68.6%. The Graz Lagrangian model showed the ability to simulate air quality problems in the Krasnoyarsk greater area conditions.

Viscoelastic Coupling Dampers for Enhanced Multiple Seismic Hazard Level Performance of High-Rise Buildings

2018 ◽  
Vol 34 (4) ◽  
pp. 1847-1867 ◽  
Author(s):  
Renée MacKay-Lyons ◽  
Constantin Christopoulos ◽  
Michael Montgomery
Keyword(s):  
Seismic Hazard ◽  
Structural Damage ◽  
Time History ◽  
Coupled System ◽  
Nonlinear Time History Analysis ◽  
Coupling Beams ◽  
Restoring Force ◽  
High Rise ◽  
Amplitude Maximum ◽  
Hazard Level

Viscoelastic coupling dampers (VCDs) are installed in lieu of traditional reinforced concrete (RC) coupling beams in high-rise buildings to provide distributed supplemental damping for all dynamic loading conditions without affecting the architectural layout. When distributed effectively over the height of the building, VCDs provide viscous damping in all lateral modes of vibration and an elastic restoring force that enhances the lateral stiffness of the coupled system. In this paper, a first extensive numerical case study is carried out to compare the seismic performance of a conventional coupled shear wall high-rise building to a high damping alternate of the same design in which VCDs replace all diagonal RC beams in the core to enhance its seismic resilience. The added damping from VCDs is intended to reduce the peak responses under low amplitude earthquakes, but for larger amplitude maximum credible earthquakes, the peak responses are similar; however, structural damage is greatly reduced. Three seismic hazard levels were investigated, and the results indicate that the use of VCDs reduces peak floor accelerations, story drifts, and story shears over all seismic intensities. Nonlinear time-history analysis results also highlighted the improved resilience of the VCD structure at the maximum credible seismic hazard level where the use of VCDs eliminated all damage to coupling beams that would otherwise require repair over most of the height of the building.

Sign in / Sign up

Export Citation Format

Share Document