机构地区:[1]重庆大学土木工程学院,重庆400045 [2]湖南大学土木工程学院,长沙410082
出 处:《钢结构(中英文)》2024年第1期1-28,共28页Steel Construction(Chinese & English)
基 金:国家自然科学基金项目(52378133,51890902);重庆市自然科学基金项目(CSTB2023NSCQ-MSX0758)。
摘 要:钢管混凝土柱承载力高、抗震性能优越、造价适中,是超高层结构和大型重载结构常用的竖向承重柱形式。方钢管混凝土柱与圆钢管混凝土柱相比,其截面相对开展,具有抗弯刚度大、抗弯承载力高、节点构造简单、加工施工方便、便于建筑空间布置与装修等优点,因此其在实际工程中应用广泛。然而,研究表明方钢管混凝土的组合效应较弱,需在其钢管内采取加劲措施以提升钢管与混凝土之间的组合作用;同时通常还需在方钢管内焊接剪力连接件提高钢管与混凝土界面的纵向剪力传递能力。已有加劲形式可归纳总结为点约束、横向封闭式约束及开放式纵向线约束。在方钢管的两邻边设置斜拉加劲肋(简称斜拉肋),是近年来新发展起来的高效加劲形式,斜拉肋可实现纵横向连续封闭式约束,同时具有剪力连接件功能。系统总结了斜拉肋加劲钢管混凝土构件、节点及体系的力学性能及设计方法。在构件层面,对柱的轴压、偏压和抗震性能进行了研究,建议了斜拉肋合理构造形式、钢管宽厚比限值、斜拉肋与钢管的厚度匹配关系及轴压比限值,提出了计算斜拉肋加劲钢管混凝土柱截面压弯承载力的修正塑性应力分布方法,揭示了超短柱的受剪机理并建立了抗剪模型及剪力–剪切变形关系。在节点层面,对斜拉肋加劲钢管混凝土柱–钢筋混凝土梁节点的轴压及抗震性能进行了研究,明确了节点轴压及受剪机理,建议了节点区合理构造以达到“强节点、弱构件”的要求,提出了考虑轴压比及柱受压区高度影响的修正黏结滑移计算公式,该公式可准确预测节点区梁筋的滑移行为。在体系层面,对斜拉肋加劲钢管混凝土柱–钢筋混凝土梁框架进行了静力弹塑性分析、增量动力分析(IDA)及地震易损性分析,明确了体系的屈服机制及抗倒塌机制。研究结果表明,斜拉加劲肋集Concrete-filled steel tubular(CFST)columns have high strength,favorable seismic performance,reasonable cost,and are widely used as the main structural types in high-rise buildings and heavily-loaded structures.In comparison to circular CFST columns,square CFST columns have the advantages of relatively wide section,large flexural stiffness,high flexural capacity,simple joint details,convenient manufacturing and construction,convenient layout of building space,and easy decoration,and thus are widely used in practical engineering.However,the previous research indicated that the composite action between a rectangular steel tube and the in-filled concrete is relatively weak and can be improved by setting stiffening schemes.Meanwhile,shear connectors are usually welded to the steel tube to improve the interfacial longitudinal shear transfer capacity.The existing stiffening forms are summarized as point-open,point-closed and line-open confinement.The diagonal stiffener,welded on two adjacent sides of a steel tube is referred to as the diagonal rib;it is a new efficient stiffener developed recently and can also be used as the shear connector.This paper systematically summarizes the mechanical behavior and design methods of members,joints,and frames of concrete-filled steel tube stiffened by diagonal ribs.At the level of members,the concentric compression,eccentric compression and seismic behavior of columns were analyzed;the details of diagonal ribs,width-to-thickness ratio limits,thickness matching relationship between the diagonal rib and steel tube,and axial load ratio limits were recommended;the modified plastic stress distribution method was proposed to calculate the strength of columns under combined compression and bending;the shear mechanism of ultra-short columns was figured out,and the shear model and shear force versus shear deformation relationships were proposed.At the level of joint,the axial compression and seismic behavior of CFST column to RC beam joints were studied;the axial compression and shear mecha
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