Light Wood steel Hybrid Diaphragm’s Performance on Transferring Horizontal Loads

Abstract:

Studying the diaphragm’s in plane stiffness and its capacity on transferring horizontal loads in elastic phase, the detail of pseudo static experiment was described about a one story two span timber steel hybrid structure with light wood steel diaphragm under concentrated horizontal force. In addition, for quantifying the influence of in plane stiffness on horizontal load distribution, horizontal load transfer ability factor β was defined and the relationship of it with α discussed, which was the ratio of diaphragm’s in plane stiffness to vertical resist element’s anti resistance stiffness. Moreover, rigid diaphragm was classified according to their value. The result shows that in the case of it lays only SPF (Spruce Pine Fir) dimension lumber upon and the vertical resisting element containing barely steel frame, the diaphragm is already capable of distributing horizontal load well and α in the range of 0.5~1.0 and β about 64.0%; When α increases over 3.0 and β rises to around 90.0%, structural spatial cooperation is perfect and the diaphragm is converted to be rigid after paving cement mortar coat on it; Ultimately the diaphragm is no longer be rigid as α reduces within 1.0~2.0 and β drops to 78.0% if the light frame shear walls are installed in the vertical steel frame.