4.1.7.14.Wind Tunnel Procedure

(1) Except as provided in Sentences (2) and (3), wind tunnel tests on scale models to determine wind loads on buildings shall be conducted in accordance with ASCE/SEI 49, “Wind Tunnel Testing for Buildings and Other Structures.” (2) Where an adjacent building provides substantial sheltering effect, the wind loads for the main structural system shall be no lower than 80% of the loads determined from tests referred to in Sentence (1) with the effect of the sheltering building removed as applied to (a) the base shear force for buildings with ratio of height to minimum effective width, as described in Sentence 4.1.7.2.(2), less than or equal to 1.0, or (b) the base moment for buildings with a ratio of height to minimum effective width greater than 1.0. (3) For the design of cladding and secondary structural members, the exterior wind loads determined from the wind tunnel tests shall be no less onerous than those determined by analysis in accordance with Article 4.1.7.3. using the following assumptions: (a) Cg = 2.5 and Cp = ±0.72, where the building's height is greater than 20 m or greater than its minimum effective width, and (b) CgCp = 80% of the values for zones w and r provided in Article 4.1.7.6., where the building's height is less than or equal to 20 m and no greater than its minimum effective width.