Experimental Study on Side Pressure LBL under Tangential Eccentric Compression

Abstract

In order to investigate the eccentric compression performance of side pressure laminated bamboo lumber (LBL), 18 LBL column specimens with the slenderness ratio of 36 and cross-section of 77 mm × 77 mm were designed considering different eccentricity, and loaded under tangential eccentric compression. The test results show that the bamboo-strip connections and bamboo joints are the weak zones for the LBL columns under tangential eccentric compression, which determine the failure modes. The ultimate longitudinal and lateral strains for Face C increased with the increase of the eccentricity ratio, while these values for Face A, Face B, and Face D decreased. The discreteness for the ultimate longitudinal strain of the specimens with small eccentricity was relatively large. However, the ultimate lateral strain values for all specimens exhibited obvious discreteness. After the ultimate strength, the load-carrying capacities of the specimens with small eccentricity decreased significantly compared with those of the specimens with large eccentricity. However, the smaller eccentricity resulted in more evident discreteness of the ultimate load values. In addition, the strain was distributed linearly at the cross-section of the columns, which satisfies the plane-section assumption. Furthermore, an equation to predict the eccentricity influencing coefficient on the bearing capacity of laminated bamboo lumber columns was proposed. The predictions gave a good agreement with the test results.

Keywords:  laminated bamboo lumber,  tangential eccentric compression,  eccentricity ratio,  deformation