EFFECT OF RIDGE AND PROTRUDING GABLE WALL ON WIND LOADINGS ON LOW-RISE BUILDINGS' ROOF

In order to study the effects of ridge and protruding gable wall on the wind loading on low-rise buildings' roof, the rigid model pressure measurement tests of typical rural dwellings with four types of roofs were conducted in TJ-2 wind tunnel laboratory in Tongji University. The roofs at interest are roofs with flush gable wall and with/without ridge respectively, and roofs with protruding gable wall and with/without ridge respectively. The following results were obtained. Firstly, the existence of ridge increases the mean and rms (root-mean-squared) pressure on the windward side, so the roof lift is decreased to some extent. Furthermore, the effects get more obvious with the increasing of the ridge height for the roof with flush gable wall. However, the ridge decreases the rms pressure on the roof corners, hence, reduces the worst negative peak pressure over the whole roof. Secondly, the existence of protruding gable wall plays an important role to decrease the mean and rms negative pressure (suction) on the roof gable ends and corners, consequently, reduces the worst negative peak pressure over the whole roof greatly. However, the varying of the protruding gable wall height affects the roof pressures slightly. Finally, the existence of both the ridge and protruding gable wall is most effective in decreasing the local negative peak pressure over the roof. Such roof also diminishes the roof lift. Therefore, the conclusion is drawn that the roof with both the ridge and protruding gable wall is the most favorable roof for the wind resistance of low-rise buildings.