木質材料 Ｔｗｏ‐Ｒａｉｌ Ｓｈｅａｒ法およびＥｄｇｅｗｉｓｅ Ｓｈｅａｒ法による木質パネルの面内せん断性能評価

Abstract

Importance of the shear properties of wood-based panels has been increasing due to trends toward building code performance standardization of the building code in Japan. Shear-through-thickness properties of the panel materials, which are not defined in either the JIS and the JAS standards, were evaluated by the two-rail shear (TRS) and the edgewise shear (EWS) methods. Shear strength (τ) and modulus of rigidity (G) were determined for three types of panels used as structural materials in housing; particleboard (PB), softwood plywood (PW), and oriented strand board (OSB). Comparisons were made between the panels and between the two test methods. The results obtained were summarized as follows:From the samples tested, OSB had the highest shear properties (τ and G) and PW had the lowest, while PW had the highest bending properties. High shear properties in OSB could be due to its degree of strand alignment and the layer structure. Wire-strain gauge was used for measuring strain in the both methods; eight gauges were used for one test piece of the TRS and six for the EWS test. It was shown that G could be obtained in the EWS test. Although τs obtained from the TRS method were larger than those from EWS method for all panel types, Gs from the TRS method were almost comparable to those from the EWS. Linear relationships were found between shear properties from the TRS method and those from the EWS method. These results suggested the possibility of employing the EWS test as an alternative method for TRS.