Comparative Study On Wind Tunnel Experiment And The Wind Load Value Of Super High-rise Building Based On Many National Wind Load Standards

With the continuous advance of the urbanization in China and the advance of science and technology in building structure, the number of high-rise buildings in China has rapid growth in the past thirty years. As for super high-rise buildings, especially flexible constructions that are high, large, slender and long, wind loads have been one of the decisive design loads, and the wind effect of architectural structure has been one of the most important factors which can control the structure safety, comfort and economy. The one and only effective way to solve this problem is to conduct the study of wind effect of high-rise buildings.After decades of development, wind engineering has formed a relatively perfect system, summing up to be four main research methods as follows:theoretical analysis, wind tunnel test, field measurement, numerical simulation. Wind tunnel test is that the actual buildings and actual wind environment of atmospheric boundary layer can be simulated in laboratory room. As a research method, wind tunnel test is widely used at present. As a practical wind tunnel test, high frequency force balance technique can acquire dynamic aerodynamic force and then calculate structure dynamic responses.With the development of the research in wind tunnel test, almost of all countries have formulated special wind load codes in view of wind force proofing design. Based on pre-existing load code, issued and carried out in October of2012, the newly wind load code of our country (GB50009-2012) summarizes design experiences in recent years and consults many related contents of foreign load codes and international standard.This paper firstly compared our national wind load code with foreign developed country’s codes and then analyzed the conclusion; after that, based on a specific super high-rise building, this paper compared calculating data according many wind load codes with wind tunnel test data and acquired conclusions. The main contents can be summarized as follows:(1) According to our national newly wind load code (GB50009-2012), American wind load code (ASCE7-05), American wind load code (ASCE7-10), Japanese wind load code (AIJ2004), and ISO wind load code, this paper introduced and compared all definitions and formulas of basic wind speed, wind pressure, wind speed profile, exposure coefficient (ground roughness category), shape coefficient of building, wind fluttering factor, equivalent wind load of along-wind and cross-wind, and accelerated speed.(2) Based on specific super high-rise building and according to above-mentioned three national wind load codes and ISO wind load codes, this paper calculated all kinds of parameters, then compared and analyzed these calculated results.(3) This paper introduced HFFB (high frequency force balance technique) that is widely used as a practical wind tunnel test; then based on specific super high-rise building and according to wind tunnel test, this paper acquired wind tunnel test value. Then this paper compared and analyzed total bending moment at the bottom and acceleration magnitude on the top according to different national wind load codes based on specific super high-rise building.According to above-mentioned (2) and (3), some conclusions can be acquired as follows:(1)Compared with other three different wind load codes, the basic wind pressure, ground roughness category, shape coefficient of building and wind fluttering factor of Chinese wind load code is reasonable.(2)Compared with pre-existing load code the value of peak factor of our national load code is higher, but is still28%lower than American, Japanese and ISO wind load codes. This consequence may lead to the smaller values of wind-induced response (equivalent wind load, acceleration).(3)Our national newly wind load code gives out equivalent wind load computational formulas of super high-rise buildings with circular or rectangular section in the direction of crosswise and rotation; what’s more, our national newly wind load code considers the effect of depth-with ratio and landform and gives out correction factor of cutting-angle and re-entrant angle. As a result, our national newly wind load has a larger expansion.(4)With regard to the value of dimensional generalized wind load power spectrum in cross-wind load formula, our nation newly wind load code list it by graphical representation, which may produces deviation considering super flexible high-rise building that is sensitive to wind load. Cross-wind equivalent wind load should be further improved in the process when theoretical equations are integrated with practice of design.In the end, based on summarizing research conclusions, this paper came up with some aspect of this topic yield to be researched.