钢-混凝土组合结构抗震性能研究进展

State of Art and Future Insights of the Seismic Performance of Steel-Concrete Composite Structures

钢-混凝土组合结构因具有抗弯刚度大、承载力高、延性好和施工便捷等优点,适应国家新型城镇化建设重大需要,在城市人口密集区域和抗震设防高烈度区域应用广泛。在提高工程结构抗震设防标准的背景下,研究钢-混凝土组合结构的抗震性能,进一步提升其抗震韧性,建立具有更高韧性的钢-混凝土组合结构抗震设计方法对促进建筑结构实现“双碳”战略目标具有重要意义。为此,归纳总结了钢-混凝土组合结构抗震性能的研究进展,包括钢-混凝土组合梁、钢管混凝土柱及钢管混凝土柱-组合梁节点的滞回性能试验研究,以及钢-混凝土组合结构体系的拟静力、拟动力及振动台试验研究,讨论并比较了各种抗震分析模型及其方法,提出了当前研究存在的一些问题和尚需深入研究的方向。基于现有研究成果总结得到:1)组合梁主要依靠钢梁耗能,可采取增大钢梁截面尺寸的措施提高耗能能力。钢管混凝土柱主要依靠钢管和混凝土耗能,可采取拉筋增强约束措施直接约束混凝土,使其由脆性向塑性转变从而提高框架柱的耗能能力。与其他类型组合节点相比,刚性连接组合节点具有更好的耗能能力。2)罕遇地震下框架结构以梁耗能为主,而在超罕遇地震下仍以梁作为主要耗能部件将使工程成本大幅增加。由于超罕遇地震发生概率极低,若采取适当的增强约束措施使柱也具备耗能能力并参与耗能,则可在适当增加工程建设成本的同时使结构具有抵抗超罕遇地震的能力,此时组合结构抗震设计理念可由罕遇地震时的“强柱弱梁,梁耗能为主”向超罕遇地震时的“梁柱共同耗能”推进。3)基于平截面假定的杆系纤维模型计算软件通常适用于弹性和弹塑性小变形阶段分析,而当组合结构处于塑性大变形阶段时,结构杆件便不再符合平截面假设。对强震下组合结构体系的动力响应仿真模拟需要克服弹塑性小变形阶段的假定条件,采用适用于塑性大变形阶段结构分析的混凝土三轴弹塑性本构模型及相应的体-壳元模型是一种有效的途径。4)剪力墙结构具有整体性好、侧向刚度大等优点,但传统构造下其抗震能力较弱,可通过提升连梁和墙肢等耗能构件的耗能能力以增强结构整体耗能能力,如采用钢-混凝土组合连梁、型钢混凝土连梁或合理构造钢板连梁,以及型钢-约束混凝土或钢管混凝土墙肢等。5)工程结构在使用阶段面临着诸多灾害考验,传统方法根据不同外荷载进行独立抵抗设计,忽视了多灾害耦合作用机制,使结构综合抗灾性能难以满足使用需求,故建立安全可靠的抗多灾害设计方法和结构体系是结构工程师在防灾减灾领域的一项重大课题。

Steel-concrete composite structures that enhancing the new-type urbanization were widely used in urban and high seismic intensity areas due to their outstanding flexural stiffness,bearing capacity,ductility,and convenience of construction.In the background of upgrading the seismic fortification level of engineering structures and China's"dual carbon"target,studying the seismic performance of steel-concrete composite structures,further improving their seismic toughness,and establishing seismic design methods with higher toughness are of great significance.This review article summarizes the research progress of steel-concrete composite structures in terms of seismic performance,including hysteretic performance test on the steel-concrete composite beams,CFST columns,composite joints,as well as study on quasi-static,quasi-dynamic and shaking table tests of steel-concrete composite structural systems comparing the seismic analysis models and methods.Based on the review of existing studies,some important issues and future insights were proposed.The major fundings are as follows:1)Steel beams are the main energy dissipation components of composite beams,and increasing the cross section of steel beams can improve the energy dissipation capacity of composite beams.CFST columns using the steel tube and core concrete for energy dissipation,and the restraint measure of the column end stirrup-confined can be taken to directly constrain the core concrete,thereby enhancing the energy dissipation capacity of frame columns by making them from brittle to plastic transition.Compared with other types of composite joints,the energy dissipation capacity of rigid connection composite joints is stronger.2)Beams are the major energy dissipation components of frame structures in rarely occurred earthquakes.However,it will significantly increase engineering costs when beams act as the major energy dissipation components in extremely rare earthquakes.As is well known,the probability of extremely rare earthquakes occurring is extremely low.If some strengthened restraint measures are taken,which enable the columns to participate in energy dissipation,the structure can own the ability to resist extremely rare earthquakes while economical.Therefore,the seismic design concept of composite structures can be advanced from"strong columns and weak beams with beam energy dissipation mainly"in rarely occurred earthquakes to"beams and columns energy dissipation together"in extremely rare earthquakes.3)The fiber model based on the assumption of flat cross-section is usually suitable for the stages of elastic and elastic-plastic in small deformation,while this assumption will fail in the stage of large plastic deformation.Simulation of composite structural systems under strong earthquakes should overcome the assumed conditions of small elastoplastic deformation stage and requires using the triaxial elastic-plastic constitutive model of concrete and the corresponding solid&shell element.4)Shear wall structures with advantages of good integrity and high lateral stiffness have weaker seismic resistance.In order to enhance the energy dissipation capacity of shear wall structures,measures such as steel-concrete composite coupling beams,steel reinforced concrete coupling beams,or steel coupling beams,as well as steel reinforced concrete or CFST wall piers can be adopted.5)Engineering structures face various disasters during their use stage.Traditional design methods based on independent various external loads neglects the coupling mechanism of multiple disasters,making it difficult for the structure to meet the usage requirements under multiple disasters.Therefore,establishing safe and reliable multi-disaster design methods and structural systems is a major task for structural engineers in the field of disaster prevention and reduction.