Effect of Cyclonic Importance Factor on Industrial and Post Cyclonic Importance Steel Roof Truss

Considering the probability of cyclonic wind speeds are often exceeding the regional basic wind speeds in the coastal region, revised IS 875 Part 3:2015 presents the K4 factor (Cyclonic Importance factor) for increasing the design wind speed (Vz) with numerical values 1 .15 and 1.30 for Industrial structure and post-cyclone importance structures respectively (Such as school, Hospital, Communication tower etc.). Considering the randomness in the direction of wind – wind direction factor Kd, Considering area of structure - area averaging factor Ka, and combination of pressure and suction combination factor introduce in IS 875 part 3: 2015. This paper attempts to explore the impact of the k4, Kd, Ka, Kc factors on A-type steel trusses for 12 and 18 meter span with roof slopes 1 in 3, 1 in 4 and 1 in 5 for various building permeability conditions . The permeability conditions consist normal, medium and high building openings. The trusses have been modelled in STAAD. pro software. The results were generated for both industrial and Post cyclone importance structures. Comparisons were carried out for IS 875-1987 wind code and 2015 wind code with k4 factor including Kd, Ka and Kc factor.