9. Understanding Wind Codes and Standards: Fundamentals Behind Their Provisions

This chapter is a collection of notes describing the progress made in the last few decades on the assessment of wind loads on buildings through various codes of practice. This is necessary to understand the current code provisions for estimating wind-induced pressures on buildings, which in turn can help improve these provisions. Background studies carried out for the development of standard wind provisions almost exclusively used boundary layer wind tunnel experiments, with very limited attempts to capitalize on computational approaches. Topics presented in this chapter include: wind structure; wind speed models; wind pressure provisions for gable roof buildings with intermediate roof angles; pressure coefficients for hipped roofs; and internal pressures. It was generally observed that the current codes must incorporate the effects of upstream terrain roughness, different roof shapes and other architectural features. Advancements in Computational Wind Engineering (CFD and ANN approaches) have been discussed. Recent innovative approaches, such as wind load paths and Database-Assisted Design (DAD) using time histories of wind pressure coefficients for specific building geometries are expected to be used for the provisions of future codes of practice.