IS 875 : Part 3 : 2015 : Design Loads (Other than Earthquake) for Buildings and Structures - Code of Practice Part 3 Wind Loads

Reaffirmed 2020

1 SCOPE

1.1 This standard (Part 3) specifies wind forces and their effects (static and dynamic) that should be taken into account when designing buildings, structures and components thereof.

1.2 Wind speeds vary randomly both in time and space and hence assessment of wind loads and response predictions are very important in the design of several buildings and structures. A large majority of structures met with in practice do not however, suffer wind induced oscillations and generally do not require to be examined for the dynamic effects of wind. For such normal, short and heavy structures, estimation of loads using static wind analysis has proved to be satisfactory. The details of this method involving important wind characteristics such as the basic wind speeds, terrain categories, modification factors, wind pressure and force coefficients, etc, are given in 6 and 7.

1.3 Nevertheless, there are various types of structures or their components such as some tall buildings, chimneys, latticed towers, cooling towers, transmission towers, guyed masts, communication towers, long span bridges, partially or completely solid faced antenna dish, etc, which require investigation of wind induced oscillations. The influence of dynamic velocity fluctuations on the along wind loads (drag loads) for these structures shall be determined using Gust Factor Method, included in 10. A method for calculation of across wind response of tall buildings and towers is included in 10.3.