圆锥形中空夹层钢管混凝土纯弯构件受力性能研究

Research on the Mechanical Properties of Tapered Concrete-Filled Double Skin Steel Tubular Members Subjected to Pure Bending Load

为了研究大空心率的圆锥形中空夹层钢管混凝土纯弯构件的受力性能,对已有的试验数据进行数值模拟,采用经验证的建模方法建立了圆锥形中空夹层钢管混凝土纯弯构件力学模型。分析了典型构件受力全过程的弯矩-挠度关系曲线、荷载分配、破坏模态等力学行为;并研究了锥度、空心率和剪跨比对构件变形曲线的影响,同时分析了空心率、锥度、外钢管径厚比、内外钢管强度和混凝土强度等参数对构件承载力的影响;最后建议了该类构件抗弯承载力的计算方法。结果表明:该类构件具有良好的抗弯承载力及塑性性能,构件的弯矩-挠度关系曲线可分成弹性、弹塑性、塑性三个阶段;随着锥度的增大,构件破坏位置逐渐向最小截面靠近;空心率对构件的变形曲线影响不大;锥度、空心率、外钢管强度、内钢管强度对构件承载力的影响较为显著,而混凝土强度对其影响较小;建议的抗弯承载力计算方法与数值模拟结果吻合较好。

In order to analyze the pure bending behavior of tapered concrete-filled double skin steel tubular members with larger hollow ratio, the existing experimental data were simulated, and the validated model was used to build a mechanical model for tapered concrete-filled double skin steel tubular members.The bending moment-deflection curve, load distribution, failure mode and other mechanical behaviors of the whole process were analyzed, respectively.In addition, the influence of taper, hollow ratio and shear span ratio to the deflection curve of the member were analyzed.The effects of hollow ratio, taper, diameter-to-thickness ratio of outer steel tube, inner and outer steel tube strength and concrete strength to the bearing capacity were analyzed, simultaneously.Finally, the calculation method for bending capacity was proposed.The results show that the member has good bending capacity and plasticity, and the bending moment-deflection curve of the member can be divided into elastic stage, elastic-plastic stage and plastic stage.With the increase of taper, the failure position of the member gradually approaches the minimum section.The hollow ratio has minimal effect on the deflection curve.The taper, hollow ratio, strength of outer steel tube, and strength of the inner steel tube have a significant influence on the bearing capacity, while the concrete has less impact on it.The proposed method for calculating bending capacity is in a good agreement with the numerical simulation results.