长期荷载作用下钢-竹组合箱形柱蠕变特性

RESEARCH ON CREEP PROPERTY OF STEEL-BAMBOO COMPOSITE BOX COLUMN UNDER LONG-TERM LOAD

为研究钢-竹组合箱形柱的蠕变性能,设计制作了8根组合柱试件,以荷载水平、截面尺寸以及有无螺钉为参数,对其实施了长期加载试验,观测了组合柱在长期荷载作用下的变形发展,得到了蠕变-时间关系曲线以及蠕变系数,在此基础上通过确定组合柱蠕变与竹材蠕变间的关系提出了钢-竹组合箱形柱蠕变模型,并将蠕变计算值与试验值进行了对比分析。结果表明：钢-竹组合箱形柱的蠕变发展先快后慢,约在加载90 d后逐渐趋于稳定,长期持荷水平对蠕变的影响显著,截面尺寸有一定影响,而螺钉对蠕变大小基本没有影响;组合柱的蠕变系数为0.160-0.190,蠕变与试件初始变形相比处于较低水平;组合柱蠕变计算值与试验值在中后期表现出较高的吻合度,说明建立的蠕变模型可适用于预测钢-竹组合柱的蠕变发展和进行蠕变对构件力学性能的影响分析。

Eight steel-bamboo composite box columns were designed based on the load level,cross-section dimension and the presence or absence of screws to study the creep property. The specimens were tested to observe the deformation and development of the composite column under long-term load and the creep-time curve and creep coefficients of the composite column were obtained. Moreover,the paper proposed the creep model of steel-bamboo composite box column,and compared the calculated creep values with the test values. The results showed that the creep of steel-bamboo composite box column developed first and then slowly,about 90 days after loading gradually stabilized,the effect of long-term load on creep was significant,and the cross-section dimensions had a certain effect,while the screw had little effect on creep. The creep coefficients were 0. 160 - 0. 190,creep was at a lower level than the initial deformation of the specimen; the calculated creep values of the composite column and the experimental values showed a good agreement in middle and later period,which showed that the creep model established in the paper could be applied to predict the creep development of steel-bamboo composite columns and analyze the influence of creep on the mechanical properties.