钢管混凝土平缀管格构柱极限承载力试验研究

Experimental study on ultimate load-carrying capacities of concrete filled steel tubular battened columns

进行24根缀板式钢管混凝土格构柱轴心受压和偏心受压试验。试验参数为长细比、偏心率、柱肢间距和缀管间距。对试件的受力全过程、破坏特性与极限承载力进行分析,讨论了缀管的受力特性和缀管构造对试件极限承载力的影响。试验结果表明,钢管混凝土平缀管格构柱中缀管以受弯为主、应变较大,缀条式格构柱中缀管以受轴力为主、应变较小;柱肢间距和缀管间距对试件承载能力有较大的影响;随着长细比增加,试件破坏特性从局部压屈变为整体破坏;长细比和偏心率两个参数对缀板式钢管混凝土格构柱极限承载力的影响基本上是独立的,可以采用分项系数相乘来考虑二者的共同影响;稳定系数与偏心率折减系数可以采用与缀条式格构柱相同的方法计算,但其剪切变形对极限承载力的影响要大于缀条式格构柱;给出了应用图表法的换算长细比计算方法。

Tests of 24 concrete-filled steel tubular （CFST） battened columns were carried out. The experimental parameters were column slendemess, load eccentricity, chord spacing and batten spacing. The whole load-carrying process, failure modes and ultimate load-carrying capacities of the specimens were analyzed in this paper. The mechanical behaviors of batten members and their effects on ultimate load-carrying capacities of the specimens were discussed in detail. Test results show that, bending moment is dominate force in battens of the specimens unlike axial force in lacing bars in the laced column, and strains of battens are much larger than those of lacing bars. Chord spacing and batten spacing of batten column affect load-carrying capacity obviously. With the increase of slendemess the column behavior shifts towards slender column from stub column. Eccentricity and slenderness are parameters affecting the load-carrying capacities of CFST battened column independently which can be used as subentry-parameter multiplication formula for the corresponding effect both. The stability coefficient and eccentricity reduction coefficient of CFST battened column are adopted by the same method of laced column, but the effect on load-carrying capacities for deformation in shear is greater than the latter. A calculation method for equivalent slenderness ratio by a graphical method is presented.