波纹钢管混凝土工作机理及静动力性能研究

Concrete-filled tubular (CFT) structures are exposed to increasingly complex environments with ever-broadening applications. Anticorrosion maintenance is generally difficult and expensive for established structures exposed to the air. Due to the superior corrosion resistance and the high lateral stiffness of the corrugated steel pipe (CSP), concrete-filled corrugated steel tube (CFCST) is proposed which has similar working mechanism with the tube confined concrete columns. Such innovative composite member has many advantages including free of maintenance, high load-bearing capacity, excellent ductility, strong interfacial bonding strength between CSP and concrete, and ease of construction, etc., and hence has a promising future in the structural applications. However, the available related research work is limited, the confinement effect and the static and seismic performance of the composite member has not been well understood. Besides, neither the non-uniform confinement effects induced by moment nor the reduction of confinement effects induced by shear stress was considered in the available stress-strain model for circular tube confined concrete columns when subjected to eccentric, torsional, shear or reciprocating loading. In this context, this project will conduct extensive experimental and numerical study on CFCSTs to investigate their static and seismic behaviors. Particular attention will be drawn on the mechanism of the confinement effects. The model equations to predict the stress-strain responses of the steel tube and the concrete core for CFCSTs will be proposed respectively accounting for the influence of the corrugation parameters and the combined axial, flexural, shear and torsional loads on the confinement effects. Designing approaches will be established for the prediction of the static and seismic resistances of such columns. The research outcome of this project will establish the foundation for the development of CFCSTs.

随着钢管混凝土应用领域日益拓宽，其所处工作环境日渐复杂，对于直接外露的建筑物与构筑物中的钢管混凝土，面临着维护成本高、操作危险性大等突出问题。申请人基于镀锌波纹钢管耐腐蚀性强、侧向刚度大等特点，提出了波纹钢管混凝土这种新型组合构件，其力学性能与钢管约束混凝土相近，并具有服役期内可免维护、承载力高、延性好、界面粘结性能好、施工方便等优点，应用前景广阔。波纹钢管混凝土的研究工作尚处起步阶段，其约束机理、静动力性能亟待研究，同时，现有钢管约束混凝土中钢管和混凝土纵向应力-应变关系均未考虑弯矩引起的纵向应力不均匀性，以及剪力或扭矩引起剪应力对约束效应的削弱作用。本项目将对波纹钢管混凝土柱静力性能与抗震性能进行深入研究，重点揭示波纹钢管对核心混凝土的约束机理，建立可考虑波纹参数及多种荷载耦合作用对约束效应影响的核心混凝土纵向应力-应变关系表达式，建立波纹钢管混凝土成套设计方法，为其应用推广奠定基础。

波纹钢管混凝土作为一种新型组合构件，可有效解决传统钢管混凝土的外管腐蚀问题，且保持了钢管混凝土特有的力学性能优势和施工便捷性，具有广阔的应用前景。目前，针对其基本力学性能的研究尚处起步阶段。为此，项目针对波纹钢管混凝土柱的基本静力和抗震性能开展了系统研究：完成了波纹钢管混凝土柱的轴压、偏压试验和有限元模拟，明晰了轴压和偏压荷载作用下波纹钢管对核心混凝土的非均匀约束机理，提出了等效侧向约束应力的简化计算方法，构建了波纹钢管混凝土轴压、偏压构件的截面承载力和构件稳定承载力计算公式；完成了纯弯、纯剪、纯扭单一荷载作用下和压、弯、剪、扭多种荷载耦合作用下波纹钢管混凝土柱的力学性能试验和有限元分析，提出了波纹钢管混凝土柱的纯弯、纯剪和纯扭承载力计算公式以及其弯-剪、压-扭、压-弯、弯-扭、压-弯-扭耦合作用时的承载力相关方程；完成了波纹钢管混凝土柱的压-弯滞回试验和精细化有限元分析，构建了波纹钢管混凝土柱的压-弯滞回恢复力模型。项目揭示了波纹钢管对核心混凝土的约束机理，建立了波纹钢管混凝土柱成套的设计方法，为其应用推广奠定了基础。