高强钢双肢连接受压杆塔构件稳定机理及设计理论研究

The application of high strength steel can reduce structure weight, reduce cost, save energy, and achieve good economic and social benefits. With the latest development of pole and tower structures in our country and foreign countries, adopting the method of combining numerical simulation, experimental study and theoretical analysis, this project has deeply investigated the compression stability of the high strength pole and tower compression members with two legs connection. Created the numerical model which can accurately simulate the end restraint and the initial imperfection of the member, studied the influence of steel grade, member section type, slenderness, the width-to-thickness ratio, the initial geometrical imperfection and residual stress distribution pattern etc on the compression buckling behaviour of the high strength pole and tower compression members with two legs connection. Based on the research work of this project including material characteristic tests, residual stress distribution measurement tests, short columns compression tests,sub-structure tests and members axial compression tests, focused on the impact of the problems, which were the researches of the residual stress distribution of high strength steel cross-section, the relationship between steel grade and the plate width-to-thickness ratio or the critical slenderness ratio, and the correlation influence between plate local buckling and the overall instability of compression member, the quantitative relationship and calculation equations of the design method between local buckling and the overall buckling loading capacity of the high strength pole and tower compression members with two legs connection have been proposed. The research achievements of this project are significantly helpful and valuable to clarify the instability mechanism which steel strength affected the stability of members under axial compression, to reveal the quantitative correlation relationship between plate local buckling and the overall instability of compression member, to supplement the current design method and theory of pole and tower structures, to enlarge the engineering applications of high strength steel, and to achieve the development goal of energy conservation and the reduction of emissions.

使用高强钢能减轻结构自重、降低造价、节约能源，具有良好的经济和社会效益。本项目结合国内外杆塔结构的最新发展，采用数值模拟、试验研究和理论分析相结合的方法，深入研究高强钢双肢连接杆塔构件受压稳定性能。利用能够准确模拟构件端部约束条件和初始缺陷的数值模型，研究钢材强度、截面形式、长细比、板件宽厚比、几何初始缺陷及截面残余应力模式等因素的影响。结合高强钢截面残余应力测量试验、短柱受压试验、子结构试验和构件轴心受压试验，着重研究高强钢截面残余应力分布、钢材强度与板件宽厚比和临界长细比关系、板件局部屈曲与构件整体失稳影响等问题，提出高强钢双肢连接杆塔构件局部屈曲、整体稳定承载能力及其相关性失稳的设计方法。项目成果为阐明钢材强度影响轴心受压构件的失稳机制、揭示高强钢轴心受压构件整体失稳与板件局部失稳的相关性定量关系、完善现行杆塔结构设计理论、推广高强度钢材的工程应用和实现我国节能减排目标具有重要意义。

长期以来，我国钢结构规范用钢仅局限于Q420强度等级以下的钢材，虽然我国已试建了一些高强钢杆塔结构工程，但对此类结构中使用高强度钢材的铁塔主材，其受压稳定性能的试验研究和理论分析仍然不足，而且也尚无专用设计此类高强钢构件的设计方法。本课题采用数值模拟、试验研究和理论分析相结合的方法，对具有初弯曲、初偏心和初始残余应力等缺陷的高强钢轴心受压构件的稳定机理进行研究。调查分析高强钢杆塔结构设计特点和存在的问题；基于有限元法对轴心受压高强钢构件受力性能进行三维非线性仿真研究；及对具有初始缺陷的轴心受压高强钢构件稳定性能进行试验研究，深入分析影响高强钢构件受力性能的端部约束条件、失稳模态、长细比与板件宽厚比关系及截面残余应力分布等影响因素，着重探索高强度钢材的本构关系、截面残余应力模型，以及高强钢轴心受压构件稳定系数柱子曲线模型、宽厚比限值条件和临界长细比界限等问题，并在理论分析的基础上提出实用设计方法。项目研究成果为阐明钢材强度影响轴心受压构件的失稳机制，揭示高强度钢材轴心受压构件整体失稳与板件局部屈曲的相关稳定机理具有重要的意义，可为研究高强度钢材的受力性能、完善高强度钢材的设计理论和推广使用高强度钢材的工程应用提供理论依据。