Equivalent Static Wind Loads on Long-Span Roof Structures

Abstract

The loads on buildings and structures caused by the buffeting action of wind have traditionally been analyzed using the gust loading factor (GLF) approach in most codes and standards. In the GLF approach, the equivalent static wind load (ESWL) for structural design is equal to the mean wind force multiplied by the GLF. However, this method fails to provide meaningful guidance in cases with zero mean response. This paper presents a new description of the ESWLs on long-span roof structures based on the load-response-correlation approach, which eliminates the shortcoming of the GLF. The ESWL for a given peak displacement response is expressed in terms of the mean and dynamic components; and the wind loading inputs are determined based on wind tunnel test results of multiple point pressure measurements on rigid structural models. It is noteworthy that in the proposed approach the total dynamic response is directly calculated by the complete quadratic combination approach, in which there is no need to separate the response into the background and resonant components and meanwhile the contributions of multimode response and modal response correlations are taken into consideration. Moreover, unlike existing approaches, it is not required to calculate the correlation of the load and the response, which is difficult to determine by conventional methods. Finally, an extra-long-span roof structure, which is the world's longest spatial lattice structure, is considered to illustrate the determination of the ESWLs by the proposed approach and to demonstrate its effectiveness in the design and analysis of long-span roof structures. It is shown through an example that the proposed approach can be used in conjunction with wind tunnel tests in predicting the response components not directly measured from the model tests and providing the design loads accurately.