螺旋筋增强外包型钢混凝土柱偏压性能

Eccentric compression behavior of spiral stirrup confined steel lattice reinforced columns

为了研究螺旋筋增强外包型钢混凝土柱的偏压受力性能,设计并制作了22个试件(其中螺旋筋增强外包型钢混凝土柱试件19个和外包型钢混凝土柱对比试件3个)并进行偏心受压静力加载试验,观察试件的破坏过程,剖析失效机理,获取了其荷载-挠度曲线、荷载-应变曲线、截面应变分布和刚度退化曲线,并分析了箍筋间距、偏心距、径长比(D/a,D为螺旋筋约束直径,a为柱截面边长)、长径比、缀板间距、角钢配钢率和纵筋直径等参数对其承载力和抗弯刚度的影响。研究结果表明:相比外包型钢混凝土柱,螺旋筋增强外包型钢混凝土柱在破坏时混凝土的压溃剥落程度更小,荷载-挠度曲线下降段更为平缓;截面内型钢的环向应变呈线性分布,螺旋箍筋的应变呈非均匀分布;螺旋筋增强外包型钢混凝土柱的偏压承载力和抗弯刚度相比外包型钢混凝土柱分别提高了4%~25%和13%~39%;偏压承载力及抗弯刚度均随着箍筋间距、缀板间距、偏心距和长径比的减小而提高,随径长比的减小而降低;刚度退化速率随着螺旋箍筋间距、缀板间距和径长比的增大而提高。

To investigate the eccentric compression performance of spiral stirrup confined steel lattice reinforced concrete(SSCSLRC) columns, 22 specimens, including 19 SSCSLRC columns and three steel lattice reinforced concrete columns, were designed and tested under eccentric loading. The failure process and mechanism of specimens were revealed. The load-lateral deflection curves, load-strain curves, strain distribution of cross-section, and stiffness degradation curves were obtained. The load-carrying capacity and flexural stiffness were studied using parameter analysis of spiral stirrup spacing, eccentricity, the ratio of diameter and steel edge, ratio of height and cross-section length, steel batten spacing, steel ratio, and reinforcement ratio. The results show that compared to steel lattice reinforced concrete columns, the crashing of concrete of SSCSLRC column is smaller, and the descending branch of the load-lateral deflection curves is smoother. In the cross-section, the transverse strain of steel is linear, and the transverse strain of spiral stirrup is inhomogeneous. The load-carrying capacity and flexural stiffness of SSCSLRC columns increase by 4%-25% and 13%-39%, respectively, compared with those of steel lattice reinforced concrete columns. The load-carrying capacity and flexural stiffness all increase as the spiral spacing, steel batten spacing, eccentricity, ratio of height and cross-section length decrease and decrease as the ratio of diameter and steel edge decreases. The rate of stiffness degradation increases with the increase of spiral spacing, steel batten spacing, and the ratio of diameter and steel edge.