トルシア形高力ボルトを用いた摩擦接合により一体化した鋼木複合断面軸力材の曲げ特性

Abstract

Although timber structures are advantageous for their cost and fabrication, there is a difficulty in obtaining large members and assuring strength in joints. Composite section members with steel plates sandwiched with timber sections can overcome these disadvantages; however, an effective method is required for their connection. In this research, a simple shear (friction type) connection using torshear-type bolts is developed and the connection properties are experimentally examined. Also, the buckling strength of the composite members is analytically evaluated using the obtained test data. Furthermore, relaxation of the bolt tension due to drying shrinkage and creep in timber was examined for 180 days. The initial shear stiffness of the connection (tested one day after bolting) is 50-75kN/mm, while the first peak strength is greater than 20kN. The relaxation of the stiffness is limited (the initial shear stiffness is 57-86kN/mm, and the first peak strength is 29-43kN); however, the tension in bolts and the peak strength are degraded to 20% and 40%, respectively. Analytical evaluation reveals that the connection failure does not control the buckling strength of the composite members.