The buckling collapse of single layer reticulated cylindrical roofs is investigated under uniform snow loading. Practical configurations for roofs are analyzed considering various span length, aspect ratio of planform, and member slenderness. The collapse strength calculated on the basis of the material and geometrical nonlinearities are compared with the elastic linear buckling loads, firstly. Then the member buckling stress of cylindrical roofs are represented as a function of generalized slenderness against a key member for overall strength of roof, which is often used, as an equivalent slenderness, for buckling design of beam-columns in frames. Finally, it is discussed by comparison with numerical results in frequency histogram and the buckling strength estimated from such an equivalent column slenderness that the prediction of buckling collapse loads, only according to linear buckling analysis, may be evaluated its possibility.

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The purpose of this study is to clear the mechanism of spreading of the styles and materials concerning newly built detached houses in Japan.
1) The spreading of outside materals is mainly influenced by climate, and the spreading of inside materals is mainly influenced by urbanization. Outside materials have larger regional differences than inside materials.
2) Recently, "northern style" is forming from Hokkaido to Tohoku district, and "modern style" is forming in Tokyo, Osaka and their neighbor district. As a result, the spreading of "traditional style" is declining by the two styles.
3) Newly built detached houses in Tohoku district are greatly influenced by the styles in Hokkaido and Tokyo, but they have regional differences.

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Long-term evaluation of the sliding performance of coated steel roofing and a technique for maintenance of roofs designed to facilitate on going disposal of snow by sliding are examined. Properties of coated steel roofing change with time due to chemical deterioration caused by ultraviolet rays and mechanical deterioration caused by sliding snow. With polymercoated steel roofing there is a period of about 18 years after initial deterioration during which sliding performance remains constant. Furthermore, changes of sliding performance with time of this type of roofing can be evaluated based on adfreezing strength and coefficient of friction at the interface between the snow and roofing material. Hence, it is effective to evaluate the sliding performance which corresponds to the deterioration curve over time. In addition, it is necessary to plan the maintenance of the sliding function of the roof in consideration of the deterioration curve.
From the above-stated facts, it is necessary to consider the influence of the environmental deterioration factor corresponding to the deterioration mechanism of the material to estimate the service life of the roofing material. A basic concept of the material design technique which can be applied to the sloped roof was clarified by this research.

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