STUDY OF SHORT-TERM FLEXURAL BEHAVIOR FOR GLUE-BAMBOO AND LUMBER BEAMS UNDER DIFFERENT PRE-STRESSED STATES

Abstract

After a new kind of steel-lumber composite member, named as pre-stress glue-bamboo and lumber beam, was proposed by project team, the bending test was conducted on 12 groups of pre-stress glue-bamboo and lumber beams and 4 groups of ordinary glue-bamboo and lumber beams, and from the ways of failure mode, ultimate load, load-deflection curves and load-strain curves, the influence of pre-stressing tendons number and pre-stress value on glue-bamboo and lumber beams were researched. The result showed that: under the same pre-stress value, with the increase of pre-stressing tendons number, the beam ultimate load and stiffness increased. Under the same pre-stressing tendons number, with the increase of pre-stress value, the beam ultimate load increased, and the stiffness of pre-stressed beams was better than ordinary beams, while the change was small. Compared with ordinary beams, under the same section size, the bearing capacity of pre-stress beams was 1.76~5.66 times of ordinary beams. With the same bearing capacity, pre-stress could save bamboo-lumber composites 13.28%~51.98%, and reduce cost 1.95%~39.61%. Finally, the bearing capacity calculation formula for this kind of member was proposed and verified, which provide a reference for practical engineering.