Panel Shear Performance of Bearing Wall Made of Diagonal Plywood
Susumu KAWAMURA, Hiroshi OHATA and Koji MURATA
Abstract:It is known that the shear performance of plywood depends on the grain direction of veneer sheets, and if veneer sheets are oriented 45 degree against the lateral sides, it indicates highest shear performance. Authors produced experimentally the diagonal plywood, which were laminated parallelogram veneers oriented diagonally against the lateral sides. The in-plane shear performance of the bearing wall, which joined diagonal plywood to the frame with the nail spaced 50mm to 150mm apart, was evaluated by racking test. When the nail space was shortened, load at yield point increased, but maximum load of diagonal plywood was almost equal to standard plywood. The comparable result was also obtained from the lateral nail resistance test. In conjunction with this, shear strain distribution of panel was measured by digital image correlation (DIC), and approximate shear modulus of panel could be calculated from load-strain curve. Shear strain of diagonal plywood was lower than that of standard plywood. The bearing wall using diagonal plywood indicated large initial stiffness. As a result, it was concluded that bearing wall using diagonal plywood indicates higher reference shear strength. In order to increase the shear strength that is added to diagonal plywood, it is effective if the interval of nail is to some extent shorter than 150 mm, which is the specification of wall index 2.5 of bearing wall using standard plywood. Shear modulus of full-sized diagonal plywood was about 4 times as much as that of standard plywood. Key Words:Bearing wall, Racking test, Diagonal plywood, Digital image correlation, Shear modulus, Nail space