460Mpa高强度GJ钢基于性能的计算模式研究

High strength steel has been widely used in building steel structures and there are quite a lot of studies about 400 MPa high strength steel. GJ structural steel, which is developed recently, is a new type of high performance steel and the research studies and usage experiences about GJ steel are still limited. In the previous study, the applicant of this proposal found that test set-up rigs might have great influence on the stability resistances of flexural members, which may explain why the recent research studies focus on compressive members rather than flexural members. The applicant will try several types of test set-up rigs and compare the tests results between different test rigs, which may be critical for the experimental study and which can also help to achieve the expectation. This project will conduct research studies about 460 MPa high performance GJ structural steel. Sectioning method will be used to obtain the residual stress distribution modes of Q460GJ steel welded sections. Based on full scale tests, the stability behaivour of H section, box section and cruciform section compressive members under axial and eccentric compressive loads, and the stability behaivour of mono-symmetric and biaxial symmetric H section flexural members will be investigated. After finite element model validation by using experimental results, parametric studies will be adopted, which can help to obtain more data. According to the reliability verification of ISO2394, the 460 MPa GJ structural steel performance-based calculation model will be established. Finally, the design parameter suggestions of GJ steel will be proposed.

建筑钢结构采用高强度钢材趋势已经确立，400Mpa级高强度结构钢研究已积累较多成果。GJ钢性能优异但开发在后，所涉研究刚起步，使用经验不足的状况有待改变。申请者在前期研究中发现试验装置对受弯构件整体稳定承载力有很大影响，这似乎解释了近年来高强钢研究报道集中于受压试验而回避受弯试验的原因。申请者所在课题组设想了几种不同的试验装置，陆续尝试试验作出比较，获得预期结果，有望在试验研究阶段发挥决定性作用。课题拟围绕460Mpa高性能GJ结构钢性能开展工作：采用切条法测试Q460GJ钢中厚板焊接截面残余应力分布规律；基于足尺试验，了解H形、箱形和十字形截面受压（含轴压和压弯）构件及H形（含单、双轴对称）截面受弯构件整体稳定性能；基于试验数据以有限元手段，扩展试验成果；构建460Mpa GJ结构钢基于性能的计算模式，遵循ISO2394作出可靠性论证；最终给出GJ钢的设计参数应用建议。

高强度高性能钢材在国内已有大量使用，我国《钢结构设计标准》已经将Q345GJ钢列入推荐使用材料，但针对400MPa及以上GJ钢的研究还不充分，现有规范、标准关于普通材料构件的计算方法是否适合400MPa及以上GJ钢构件，尚需研究加以验证。.课题组基于对Q460GJ钢焊接构件残余应力的试验研究，揭示了薄板、中厚板Q460GJ钢焊接H型截面、箱型截面残余应力的分布规律；分析了试验方法对受弯构件整体稳定承载力试验结果的影响，提出了两套能准确模拟受弯构件边界条件的支撑和加载方案；通过对跨中无侧向约束和跨中有一个侧向约束单点加载简支梁整体稳定的足尺试验和数值模拟，揭示了Q460GJ钢焊接H型截面受弯构件整体失稳的破坏机理和力学性能；通过对两端铰接轴心受压构件的足尺试验和数值模拟，揭示了Q460GJ钢焊接H型截面、焊接箱型截面轴心受压构件整体失稳的破坏机理和力学性能；通过对不同偏心率的两端铰接偏压构件的足尺试验和数值模拟，揭示了Q460GJ钢焊接H型截面、焊接箱型截面压弯构件整体失稳的破坏机理和力学性能；分析了以上研究结果与国内外主要国家或地区规范计算结果的差距，对这些规范计算Q460GJ钢构件的承载能力的适用性进行评估，并基于我国《钢结构设计标准》及《建筑结构可靠性设计统一标准》，就Q460GJ钢受弯构件、轴心受力构件、压弯构件稳定承载力计算的可靠度进行研究，分别提出了Q460GJ钢抗力分项系数和强度设计值的建议值。.课题组圆满完成了申请书上的各项研究任务，并及时公布课题组的研究成果，期望能丰富高强度高性能钢相关研究成果，为推广使用高强度高性能钢提供基础数据。