Study on Prestressed Laminated Strand Lumber and its Load-Carrying Capacity

Abstract

Owing to some problems in the existent plywood products such as weak shear capacity and weak wear intensity, as while as the large consumption of crude wood resources, prestressed laminated strand lumber (PLSL) is proposed in this paper, in which the multiple integration method and prestressed technology are adopted to obtain a higher strength. More significantly, used wood can be reused as the raw material of PLSL, then the crude wood will be conserved and the cost will be lowered. To study its mechanical properties, the commercial software ANSYS is adopted to establish the finite element models of PLSL. The diameter and spacing of prestressed steel wire, the magnitude of the prestress and the width of the lumber are some factors considered. Based on the nonlinear finite element buckling analysis of these lumbers, some major conclusions are summarized as follows: (1) The improvement of strength is comparatively obvious to use PLSL compared with the traditional plywood products; (2) The ultimate bearing load is rising along with the increase of the diameter of the prestressed steel wire and the width of the lumber; (3) The ultimate bearing load is descending with the increase of the spacing of the prestressed steel wire; (4) The ultimate bearing load is rising along with the increase of the magnitude of the prestress at first, but when the prestress reaches a certain level, the ultimate bearing load starts to descend.