WIND-TUNNEL TESTS TO DETERMINE THE WIND FORCES ON ROOF BLOCKS FOR EXISTING BUILDINGS

A series of wind tunnel tests were conducted on the behaviour of roof blocks in strong wind. Roof blocks were 450 mm X 450 mm X 50 mm square plates developed for improving heat insulation of roofs of existing apartment houses. Models (1:50) of five-storey buildings of rectangular plan and 1:50 miniature roof blocks made of aluminium were used. Wind speeds at which roof blocks were blown off were investigated. The following results were obtained. (1) Wind speeds at which one or more roof blocks are first blown off with internal volumes under roof blocks are lower than those without internal volumes. (2) Wind directions congruent-to 45-degrees-C are most critical. (3) Maximum wind force coefficients corresponding to the minimum wind speeds for roof block blow-off at a wind direction of 45-degrees are 1.2-1.8 and 0.8-0.9 with and without internal volumes, respectively. (4) Interlocking systems which connect the roof blocks are effective in raising the wind resistance.