Analysis of wind load spectrum of super tall buildings with round section in hilly terrain wind field

In order to get wind load and wind induced response of super tall buildings in hilly terrain wind field, effect of changing of turbulent intensity on wind loads must be known. 4 kinds of turbulent wind field are simulated, and 3 super tall building models with round section of different aspect ratio are manufactured. Effects of turbulent intensity, aspect ratio and layer height on along-wind and across-wind load are discussed. Different models are used in fitting of wind load spectrum on each direction. Parameters of load spectrum models are secondary fitted based on turbulent intensity and aspect ratio. Mathematical models of wind load spectrum of super tall buildings with round section in hilly terrain are preliminarily established. At last, an example is provided. According to vertical profile of mean velocity, turbulent intensity and mathematical model of wind load spectrum, wind induced dynamic response of super tall buildings in hilly terrain and flat terrain are compared.     

Research of Wind Load on the Surface of YingLi Building in Chongqing

Considering the complicated distribution of wind load on the surface of the tall building, the 1:300 scale model test of YingLi building is completed in the No.2 environment wind tunnel, which belongs to the State Key Lab of Environmental Engineering College, Beijing University. Based on the calculation and analysis of the test results, this paper discusses the coefficient of wind-induced vibration and shape coefficient of wind load , gives the maximum and minimum value of surface wind load, which can be used for the wind resistant design and insure the security of the building under 100 years return period wind load.     

Research on the Body Coefficient of Complicated Tall Buildings

Considering the complication of the coefficient of wind-induced vibration for tall buildings,the scale 1:300 model test of Ying Li Building is completed in the second wind tunnel of Beijing University.Based on the calculation and analysis of the test results,the static and dynamic wind pressure acting on the building can be obtained and the value of the coefficient of wind-induced vibration for this tall building can be solved directly,thus a new way is laid for the research of complicated tall buildings.     

THE STRUCTURE SPACE ANALYSIS OF THE MAIN TALL BUILDING OF CHONGQING JIANGBEI COMMERCIAL CENTER

The determination of the structural plan of the main tall building of ChongqingJiangbei Commercial Center is introduced. In anti-seismic analysis,bend-torsion coupling vibrationis compared with plane vibration.Earthquake actions from any different directions for the structureare analysed also.The result of using direct dynamic analysis method is compared with that of usingSRSS method.     

Load dynamic matching of supply and demand side based on the utilization of urban sewage heat energy

Flowing dynamic characteristics and its temperature dynamic characteristics of a three-level sewage pipe network in Chongqing were analyzed. A mall's building whole year load was simulated. In the adverse condition of wastewater flow, the market construction peak discharge heat was compared with the sewage heat load, the balance between the most adverse flow and the building demand was found. Explored supply and demand matching method between urban sewage and city building load in flow adverse condition to take full advantage of the urban sewage cold and hot resources. the composite system was adeptcd to make up the most unfavorable flow time of sewage average heat load and the construction load difference; it also puts forward principle of load sharing and control strategy aimed at compound system.     

Gear-bearing coupling dynamics characteristics of wind turbine planetary gear transmission system under variable load

Considering that the transmission system of wind turbine works in complex and changing load environment caused by stochastic wind speed,this paper uses sparse least squares support vector machine(SL-SVM) to simulate wind speed of true wind field,and obtains time-varying wind load caused by stochastic wind speed. The lumped-parameter method is used to develop a dynamic model of planetary gear transmission system of wind turbine coupled with bearing. The model includes the varying wind load,time-vary mesh stiffness of gear pair and time-vary stiffness of rolling element bearing. The numerical method is used to simulate the dynamic performance of planetary gear system of Multibrid Technology Wind Turbine with 1.5 MW rated power. The vibration displacement responses of the transmission system are obtained as well as dynamic meshing force each pair of gear and nonlinear bearing forces. The research can provide a foundation for optimizing dynamic performance and reliable design of gear transmission system of wind generator.     

Dynamic characteristics analysis of megawatt wind turbine drive train

Since the wind turbines are installed on the flexible support tower, the drive train of the wind turbines runs under severe work conditions with varying wind directions and loads. So its failure rate is high and it is the bottle neck of the wind power development. This work presents a study which takes the coupling effect of oscillating of tower barrel and the twisting vibration of driven train into account. Using the lumped parameter method, a coupled dynamic model for the megawatt wind turbine drive train is built by considering the flexible tower barrel support effects. Then, the dynamic characteristics of the megawatt wind turbine drive train are analyzed. The Campbell chart is used in this research to analyze the potential resonance points. And the potential resonance frequencies between the cutting in and cutting out rotational speed of the drive train are obtained. Finally, Simpack is used to analyze the dynamic characteristics of drive train and verify the correctness of the proposed method.     

辽宁沿海大风天气学分型及预报指标初探

大风是一种灾害性天气,极易造成海上航运及海上渔船生产作业困难、渔业养殖设施损坏。分析沿海大风的时空分布特征,总结预报指标及构建预报概念模型,有利于深入了解沿海大风的气候特点、发生发展机理,从而提高预报准确率。利用1971—2010年辽宁沿海17个常规站日最大风速、风向资料,针对辽宁沿海的4个海区及单站的7级以上大风,对其风速和风向的时空分布特征进行统计分析,结果显示：（1）辽东半岛南部沿海地区出现日数最多,最多位于旅顺市,大风总日数为925天,平均每年23.1天;（2）辽东半岛西部、南部和东部沿海偏北大风次数要明显多于偏南大风站次数,渤海北部沿海的大风天气以西南偏南大风为最多;（3）辽宁沿海大风主要出现在春季,其中4月份最多为51天,冬季次之,夏秋季出现最少;（4）风向主要以偏北风和偏南风为主,东西风出现次数较少;（5）10月至次年2月辽宁沿海偏北大风占主导地位,4—6月份辽宁沿海偏南大风占主导地位。以NCEP再分析资料为基础,针对1971—2010年26次大风典型个例普查地面及高空影响系统,对辽宁海上大风进行天气学分型,将其分为高低压型、高压型、低压型等3种。按照不同的天气学分型对其分别建立预报概念模型,确定预报关键区并初步总结预报指标。     

Modeling and Simulation of a Novel Drive Train for Wind Turbine with Large Capacity

On the basis of a planetary transmission, a novel hydrodynamic speed controlled transmission system for wind turbines with large capacity is presented. The new drive train consists of wind rotors, planet accelerators, hydro-mechanical and synchronous generators. The dynamic mathematical model of the drive train is established. The digital simulation of speed regulation characteristics for hydrodynamic speed controlled system is studied by using Matlab/Simulink. The simulation results show that continuously variable transmission and fixed speed control can be achieved, and the drive train works well in stability and dynamic performances. They can increase the power yield from the wind, smooth the electric power output, and alleviate the load peak in the new drive train .     

龙卷风作用及核电站结构极端风荷载相关问题研究综述

在结构荷载规范中一般均不考虑龙卷风荷载,但对于某些设防要求极高的重要工程设施,如核电站,则需要考虑可能的龙卷风荷载作用。从龙卷风风场理论模型的研究发展入手,对直接风压荷载的确定、风致飞射物间接作用以及特种工程结构核电站抗龙卷风设计的研究现状进行了归纳总结,指出了龙卷风直接风压计算中考虑轴吸力作用、风场平移运动及风致扭转作用的必要性以及飞射物冲击作用应区别弹体相对刚度及端部形态对作用效果的影响。     

Dynamic Responses of the High Slender Structure Under Non-Gaussian Model of Wind Load

With reference to the effect of the quadratic component of turbulent-wind fluctuation, the statistical moments of wind load up to the 4~(th) order are derived and the spectrum densities are given based on the Fourier transformation. By means of the Gram-Charlier series, the first-order probability densities of the structure responses are then constituted with the former 4~(th) order central moments of responses. Under the independent hypothesis of the structural displacement and its derivative, whose applicability is verified by the correlation between the two signals, the joint probability density function is developed and a numerical scheme for the analysis of the dynamic behaviors of the high-slender structure under wind excitation is obtained. Parametric analysis on dynamic responses and reliability under both Gaussian and non-Gaussian models of wind load are then investigated.     

Calculation of environmental cost in the structural optimization of super tall buildings

Chinese mainland has seen a rapid construction speed of super tall buildings in recent years. Due to its huge quantity material and energy assumption, the super tall buildings exert great impact on the environment. An innovative new life cycle model is proposed for assess and optimize the life cycle environmental cost of super tall buildings. The new life cycle model has two features. Firstly the space distribution of the building materials is considered besides the time dimension, and secondly the single life cycle concept is extended to multiple life cycles to investigate the carbon footprint from the perspective of more than one life cycle. A benchmark super tall building is established to illustrate the application of the proposed new life cycle model. According to the case study results, a remarkable difference would be made in carbon emissions if the life cycle environmental cost based structural optimization method could be applied.     

Implementation of Green Building Design Strategies Needs Whole Process Control and Supervision

Whether the intention of green building design can be realized in buildings needs to be verified in practice.This study firstly investigates the basic climate conditions including the monthly average temperatures,humidity,wind directions,and wind speeds in Sydney,Australia,based on which it introduces some passive design features such as natural ventilation,thermal mass,natural lighting and shading control of an educational and office building in the University of New South Wales.Then,it reviews some problems identified from the post-occupancy stage of the building and discusses the strategies to solve the problems.Finally,it suggests that to implement the design intentions and ensure the expected performance of green buildings,attentions should be paid to supervise and direct implementation of the green design strategies and techniques in the whole process(from preliminary design,working drawing design,construction,to the occupancy stage) of building practice.     

Multiple Load Flow Solutions in Electric Power Systems Based on Genetic Algorithm

Methods for satisfying the power balance requirement and the voltage magnitude costraint are developed and incorporated into the genetic algorithm method to form a constrained genetic algorithm for solving the load flow problem.The robustness of the load flow algorithm is enhanced by the dynamic population.the technique for accelerating the convergence of the optimisation process and the network node sequencing procedure described in the paper.The efficiency and feasibility of the developed CGALF algorithm have been tested using KK 11 node system under light load and heavy load conditions.     

Seismic Analysis and Performance Assessment of 3-D FEM of a Factory Building

A whole 3D finite element model of a Large Steel Structural Factory Building is established. Then dynamic characteristics and dynamic responses are calculated by importing the seismic excitation in different three directions to evaluate its earthquake resistance. Compared with the Code for Seismic Design of Buildings, the results show that this factory building meets the requests of seismic fortification intensity 7. All the work is helpful for engineers to design similar buildings.     

PROBABILISTIC EVALUATION FOR STEEL FRAME COLUMNS OF TALL BUILDINGS

Based on properties of parameters and test data of dom-estic steel,this paper analyses the reliability and partial coefficient forresistance of steel frame columns of tall builings.The result may serveas a scientific basis.It is not only for domestic steel instead of importedsteel in building tall steel structures,but also for compiling concerendstandards.     

南方建筑非透明围护结构热工与节能设计

如何兼顾冬夏两季建筑供暖空调负荷和能耗,保证室内热环境质量,确定最适宜的热工特性,是长期困扰中国南方建筑围护结构热工与节能设计的难点。通过对夏热冬冷和夏热冬暖地区建筑在采暖、空调与自然通风条件下动态热过程的分析,研究了这一地区围护结构热特性与能耗的制约关系,以及对室内热环境与建筑热稳定性的作用机理。在兼顾冬季保温与夏季隔热的情况下,将建筑全年能耗作为控制目标,从室内热环境质量、节能效果、围护结构的安全性、可靠性、经济性和实用性等角度评价目前所采用的围护结构节能技术存在的问题,提出一种适宜南方气候的建筑围护结构热特性指标及构造形式。     

Natural outcrossing in common buckwheat

Common buckwheat is an obligate cross pollinating crop because of its sporophytic self-incompatibility system. Therefore a study to assess the extent of natural outcrossing was undertaken for two years at Morden and Portage la Prairie, Manitoba using the semi-dwarf character, which is due to a homozygous genotype with regard to a single recessive gene, as a marker. The semi-dwarf genotype was grown in 100 m rows running in four directions at 90 ° from a central 36 m² plot of a normal, tall variety. At maturity, seed samples were taken from the semi-dwarf population at designated intervals. At least 200 F₁ seeds from each sample were grown in the greenhouse to the 3-4 leaf stage and the proportion of tall plants was used to determine the percentage of outcrossing. Approximately 50% outcrossing occurred where the semi-dwarf plants were immediately next to the normal plants and then the proportion decreased with increasing distance. Although outcrossing occurred throughout the distance tested, there were no significant differences from 12 m onward from the pollen source. Lack of directional influence in outcrossing and a sharp reduction in the proportion of tall plants within a 3 m distance from the pollen source suggested that wind was not a major factor in dispersing the buckwheat pollen over long distances. Although a substantial cross pollination was limited to a few metres from the pollen source, nearly 1% outcrossing occurred even at 100 m. Since the distance in this experiment was limited to 100 m from the pollen source, the present results do not allow us to recommend the minimum isolation distance required to meet certain standards for buckwheat seed production. This revised version was published online in July 2006 with corrections to the Cover Date.     

Analysis on Effect of Traffic Loads on Landslide Stability

In the design of landslide control engineering,the effect of traffic loads has not been taken into account.The authors simplified the traffic loads as mobile dead loads and traffic dynamic load.The mobile dead load ranges from 2.34 to 6.41 kPa.The impact coefficient was chosen to denote the traffic dynamic load and ranges from 0.1 to 0.4.Using several stability analysis methods widely accepted by engineers,combining two analysis samples,by the contrast of stability tests with and without consideration of the mobile dead load or the traffic dynamic load,the authors found that when the traffic load is not taken into account,the stability coefficient of shallow layer landslide(<8m) is overrated by 4.3-11 percent or 5.8-12.1 percent in comparison with the case when the mobile dead load or traffic dynamic is taken into account respectively,that is,the influence of mobile dead loads and traffic dynamic load is cannot be neglected.In case of medium deep layer landslide or the road is passing through the anti sliding section,the influence of the traffic load is a little and can be neglected.     

Performance simulation of high-power wind turbine under the action of wind and wave

In order to research the offshore wind turbine which operates in harsh environment with transient and variable working conditions, the system is simulated and analyzed by simulation technology. The aerodynamic load of wind turbine is calculated by applying GDW theory and wave load is calculated by applying Airy wave theory. The drive chain is programmed in Matlab/ simulink and the flexible multi-body model of the wind turbine is built in Adams. The combined simulation of the wind turbine is carried out. The results of a 5 MW offshore wind turbine show that the method has excellent ability to simulate the performance almost the same as software Bladed result.