Research Of Truss Plate Connected Wood Trusses In Light Wood Construction

The floor and roof framing systems of the wood frame construction are the lightframe wood trusses system, in which there is used by metal plate connection. The metalplate connected wood trusses can be prefabricated in advance ,manufactured in batches andsave labors, lessen construction time, but is efficient and performance of joint is steadily,manufacturing is simple. It is worthy of our research in our country.It introduces materials,manufacturing, design, storage, installation and bracing of the metal plate connected woodtrusses, and analyzes factors which are affected on resistances of truss plate.The four truss plate's mechanical properties are established through testing of platejoints. To ultimate resistance of teeth, the factors are angle between load and wood grain,angle between load and major axis of plate, loading time, moisture content of wood,whether wood is handled by fire retardant treatment, end and edge instance and installationmethods and so on. In these factors, the effect of angle between load and wood grain isevident, but the effect of angle between load and major axis of plate is smaller. In addition,the selected fire retardant treatment should be not to corrosive to truss plate. The majorfactors which are affected on tensile resistances of truss plate are angle between load andprimary axis of plate and the length of extended plate and whether there are blocking injoints with extended plate. For example, if there are blocking in joint, the tensile resistanceof the extended plate with blocking is 23% of that of plate. The factors which are affectedon shear resistances of truss plate are angle between load and major axis of plate, trussquality and its size. When angle between load and major axis of plate is 60°and120°,shear resistances of truss plate can reduce by 55.5%.In some situations, the plates fail bywithdrawal of the teeth near the shear line after bucking of the plate. The paper advise thatthe conversion factor be 0.8 when we calculate the resistance of plate by gross area method.