Water leak diagnosis of tiled roofs under vibration and scattering by wind tunnel experiment
This paper describes a water leak test of roof tiles. The 100 roof tiles were set up on 10 lines and 10 rows on the pitched roof in the downstream of the flow from the wind tunnel. The flow velocity was increased gradually from the low velocity to the high velocity, and the effects of the wind on the roof tiles were investigated by the water leak test. The situation of the water leak test was filmed by video camera. Two accelerometers were simultaneously used. The roof tiles which showed significant vibration at any velocity were found in a series of experiments and the accelerometers were attached to the two neighboring roof tiles on the model roof. The water leak phenomena in the experiment by using the artificial rainfall apparatus are discussed in this paper. Some mechanisms with relatively large amplitudes at low-frequency vibrations, which caused water leak phenomena were made clear.
Researches on Vibration and Scattering of Roof Tiles by Wind Tunnel Test (Effect of Vibration on Scattering of Roof Tiles):(Effect of Vibration on Scattering of Roof Tiles)
This study has investigated the characteristics and source of the vibrating and scattering behavior of roof tiles with the aim of providing a better insight to the mechanism. 100 roof tiles were set up in 10 lines and 10 rows on a pitched roof in the downstream of the flow from a wind tunnel. These experiments were followed by series of tests where the slope angle of the roof tiles was changed. The vibrations of the roof tiles were simultaneously measured by the two accelerometers, and the motions of the vibration and scattering were observed by the high-speed video camera. The frequency response function and coherence function of roof tile were measured by an impact hammer test under no flow condition. Just before scattering of the roof tiles, both vibrations of a higher frequency mode and vibrations of lower frequency mode appeared simultaneously in the roof tiles. The values of the higher frequencies were corresponding to the values of resonant frequencies of the roof tiles. It was thought that the scattering of roof tiles was influenced by the vibration of the lower frequency mode. The frequencies of the vibration were measured by a high-speed video camera system. The values of the lower frequencies were 10Hz∼20Hz. The mechanism of the scattering of the roof tiles could be understood by means of the information from the accelerations and the images of roof tiles.
Principles of wind loading on tiled roofs and their application in the British standard BS5534
Abstract The paper shows how the presence of an impermeable backing to an air-permeable cladding reduces the wind load on the cladding. It describes the important mechanisms of wind loading for some such cases, particularly tiles over underlay, and the approximations necessary to formulate the calculation procedures of BS5534. The discussion includes the extension of the principles to roofs without underlay and wall cladding systems.