Experimental Study of Deformation Characteristic and Application on External Prestressed Wooden Beam

People have widely uesd long- history wooden buildings in the ancient and mordern architecture.But the modulus of elasticity of the wood is smaller as well as the fact that the stiffness of wood is lower. In order to solve the problem of deficiency of the stiffness of large-span wooden beam from the practical engineering, this paper presents the method of external prestressed wooden beam, and the calculation method of deflection of wooden beam through model test of 1:2 scale. In addition to it, the paper also analyzes the factors which affect stiffness of wooden beam. The result shows that stiffness of this kind of wooden beam is greatly improved compared with the common wooden beam in the same cross section. Steel has a predominant tensile characteristics, it is an effective method to reduce undue deflection of large-span wooden beam by external prestress method. This construction techniques has greatly applicational value in the reinforcement and strengthening ancient buildings and modern design and construction of large-span timber structure buildings and bridges.