加载方式对钢管混凝土轴压长柱和中长柱受力性能影响的试验研究

Experimental Research on Influence of Loading Method on Behavior of CFST Long Columns and Mid-long Columns under Axial Loads

进行4种加载方式对钢管混凝土轴压长柱和中长柱试件受力性能影响的试验研究,并与轴压短柱试验进行对比和分析。结果表明,加载方式对长柱中截面应力的影响较小,但对刚度影响较大,从而影响稳定极限承载力,其中初应力对长柱的极限承载力降低的影响比短柱明显,而与之相反,对于荷载仅施加于钢管之上的长柱,其极限承载力反而大于同样加载的短柱。随着长细比的增大,加载方式对试件套箍作用的影响有减小的趋势,且受力性能的差异也逐渐缩小。加载方式对钢管混凝土中长柱受力性能的影响介于短柱与长柱之间,但与短柱更接近。最后,讨论不同加载方式作用下长柱和中长柱的极限承载力计算方法。

Experimental research on influence of four types of loading methods on behaviors of CFST long columns and mid-long columns subjected to axial loads is carried out. The comparison between stubs and long columns is presented. Analyses results indicate that the loading methods influence the cross-section stresses of long columns slightly and the stiffness and stability limit load-carrying capacity significantly. The effects of initial stresses on load-carrying capacity of long columns are serious than for short columns. When loading is applied only on steel tubes, the load-carrying capacity of the long columns is larger than that of the short columns. With the increasing of the slenderness ratio, the influence of the loading method on the hooping effect and mechanical behavior of the members are decreased. The influence of the loading method on mid-long columns lies between long columns and stub columns, and it appears more close to latter ones. Finally, the estimating method of the load-carrying capacity of CFST long and mid-long columns under different modes of axial loading is discussed.