重组竹中长柱双向偏心受压性能试验研究

EXPERIMENTAL RESEARCH ON MIDDLE-LONG PSB COLUMN UNDER BIAXIAL ECCENTRIC LOAD

研究了重组竹中长柱的双向偏心受压性能。分别从构件的长细比、偏心角和偏心距三个方面进行了试验研究,总结了偏心受压柱的破坏模式,并分析了构件跨中的截面应变及荷载-位移的发展变化。结果表明：构件极限承载力随长细比增大显著降低;在偏心荷载作用下,偏心距较小的柱,柱中受压区边缘局部纤维首先发生压屈变形,压应变达到材料极限压应变,造成试件失效;偏心距较大的柱,柱中受拉区边缘拉应变达到材料极限拉应变,发生纵向纤维拉断,随着位移持续增大,最终出现明显的纵向裂缝,造成试件破坏;斜偏心距一定时,承载力随偏心角的变化不明显,在偏心角相同的情况下,试件极限承载力随偏心距增大而降低。

The performance of middle-long parallel strand bamboo（ PSB） column under biaxial eccentric compression was investigated. The slenderness ratio,eccentric angle and eccentricity of members were taken into consideration.The failure modes,load-lateral displacement curves and the strains development at mid-span cross-section of these columns were studied. The results showed that the ultimate bearing capacity of the columns decreased significantly with the increasing of slenderness ratio. For the columns loaded under small eccentric compression,the fibers at the surface of compressive zone occurred buckling and deformation,when the compressive strains reached the ultimate compressive strain of the material,resulting in the failure of the specimen. For the columns loaded under large eccentric compression,the fibers at the surface of tensile zone occurred fracture when its strains reached the ultimate tensile strain. If the eccentricities of applied loads were constant,there was no significant change in ultimate bearing capacity when the eccentric angles of applied loads were varying. And when the eccentric angles of applied loads were the same,the ultimate bearing capacity of columns and the eccentircities were anti-correlation.