【摘要】 施工初应力作用于内配型钢钢管混凝土柱时,钢管或钢管与型钢发生任何细微的变形或应力分布不均匀都会影响其受力性能和稳定性。因此,采用ABAQUS有限元分析软件建立施工初应力分别仅作用于钢管以及同时作用于钢管和型钢这两种典型工况下的模型,研究初应力系数β和长细比λ对荷载-变形曲线、各部件承担荷载以及对承载力影响系数k_p的影响,并进行参数分析。结果表明:上述两种作用工况下,各部件开始共同工作的时间相较于不考虑初始荷载构件的有所延迟;上述两种工况构件仅钢材先受力,当初应力系数增大时,对短柱(压缩破坏)的承载力无明显影响,但对长柱(失稳破坏)的承载力影响较大,当β=0.9时,相较于不考虑初始荷载作用构件,k_p减小13.3%。钢材先受力,当初应力系数增大,对应的初始应力及初始应变增大,使得构件提前进入弹塑性工作阶段;两种作用工况对构件初始弹性刚度有较大的影响;但对承载力及延性并无明显影响;相较而言,初始荷载的影响对长柱更加显著;在施工过程中建议初应力系数不宜超过0.5,以确保结构在长期服役阶段具有更优良的受力性能。更多还原

【Abstract】 When construction preload is applied to steel-reinforced concrete-filled steel tubular(SRCFST) columns,even slight deformations or uneven stress distributions in the steel tube or between the steel tube and the steel section can affect the structural performance and stability.Therefore,numerical models were established using the ABAQUS software to simulate two typical preload cases,where the preload was applied only to the steel tube or simultaneously to both the steel tube and the steel section.The effects of preload factor(β) and slenderness ratio(λ) on the loaddeformation curve,load distribution among components,and the load-bearing influence factor(k_p) were investigated through parametric analysis.The results indicate that the different loading cases delay the initiation of composite action of each components.In both cases,only the steel components initially carry the load.As the preload ratio increases,the bearing capacity of short columns(compression failure) is not significantly affected,while that of long columns(buckling failure) is significantly influenced.When β=0.9,k_p decreases by 13.3% compared with the case without preload.The steel is initially loaded,and as the preload factor increases,the corresponding initial stress and strain also increase,causing the member to enter the elastoplastic stage earlier.Although the two preload cases have a significant impact on the initial elastic stiffness,the bearing capacity and ductility are not significantly influenced.In comparison,the effect of the preload is more pronounced in slender columns.Therefore,it is recommended that the preload factor during construction should not exceed 0.5 to ensure better structural performance during long-term service.更多还原