Development of High Rigidity Joint and its Application to Wooden Frame Structure

According to the act for promotion of use of wood in public buildings, small-scale constructions are desired to be built of wooden materials. In addition, considering the act about long life quality housing, future wood constructions should have easy-renovation system. In those social situations, it could be said that wooden frame structure has an advantage in the room re-arrangement like steel constructions. Therefore several moment resisting joints developed for heavy timber structures have been improved and put to practical usages in recent detached houses and small-scale constructions. In practical structural design, the horizontal stiffness of wooden portal frame structure tends to be insufficient when it is designed with general-produced medium-sized glulams. One of the reasons is that most mechanical joints have low rigidity. According to the annual meeting reports of Japanese Architecture Institute for the past ten years [1], the studies on moment resisting joints of which cross section sizes of the beam were ranged from 120 x 300 to 150 x 450 mm, reported that the rigidity of mechanical joints were less than 2000 kN㺃m/rad, on the other hand, that of several glued joints achieved more than 5000 kN㺃 m/rad. Then requirements for rigidity and strength of joint were simulated by an imaginary three-story wooden structure consisting of 6 m span portal frame at 2 m interval in the first floor. In the case that the member of the cross section of more than 120 x 360 mm is used for column and beam, the mechanica