Development of Wind Loading Maps for Sri Lanka for use with Different Wind Loading Codes

Abstract

It was more than 39 years ago that Sri Lanka last established a wind loading map after the severe cyclone that struck the country in 1978. It is strongly believed that statistical methods had not been used in developing this wind loading map. Hence, the map can either overestimate or underestimate the wind speeds at least in some regions of the country. Therefore, an updated map which suits the changing climate patterns experienced in the country has become a necessity. In Sri Lanka, different wind codes are being used when designing structures to withstand wind actions. Moreover, there is no wind loading map that is suitable for use with Eurocode 1. This paper presents the development of wind loading maps for Sri Lanka using wind data obtained from 24 weather stations. The data used were the monthly maximum 3-minute average wind speeds, and monthly instantaneous maximum wind speeds, recorded over a period of about 35 and 5 years respectively. An extreme value distribution called Gringorten method was used to predict the extreme wind speeds. Maps demarcating 3-second gust and 10-minute average basic wind speeds for Sri Lanka were developed for different return periods.