Comparative study on the gust load factor in the load codes and standards of five countries

A comparison was made between the loading code for building structure of several countries: the Chinese code (GB50009-2001), USA code (ASCE7-98), Japanese code (RLB-AIJ1993), Canadian code (NBC1990), and Australian code (AS1170.2). In the first section, the gust load factor (GLF) method proposed by Davenport and used in major international codes and standards was summarized. In the second section, a comparison was made among several main parameters affecting GLF, including the mean wind speed (pressure) profile, turbulence intensity, and wind speed spectrum. (ASCE7-98), (RLB-AIJ2004), (NBC1990), and (AS1170.2) considered GLF as a constant, equal to the ″displacement gust response coefficient″; the gust response coefficient in Chinese codes and standards referred to a quantity changing with height, equal to the ″inertial force gust response coefficient″. The result shows that since USA codes and standards (ASCE7) select an average interval of 3s and other countries' codes and standards select longer average intervals, the American gust load factor is smaller than in other countries. Australian codes and standards (AS1170.2) consider similar second order fluctuating wind pressure. Canadian codes and standards (NBC) have larger turbulence intensity than other countries', making their wind spectral coefficient larger, and their background factor and resonance factor smaller than other countries. Japanese codes and standards (RLB-AIJ) have the smallest turbulence intensity, which leads to the biggest size reduction factor and the smallest gust load factor.