Advanced seismic force resisting systems for cold-formed steel framed building structures

冷弯薄壁型钢框架建筑是一种复杂的结构体系，在地震作用下经历着生命周期中最苛刻的要求。AISI S400中介绍的当前CFS横向系统旨在用于1至3层的建筑。鉴于城市中心的人口不断增加，有必要发展更高和更大的建筑，以更好地优化我们城市的土地利用；即，中心采用高达8层的中层建筑为框架。在设计水平的地震中，对这种建筑物施加的力和变形要求需要开发一种横向框架系统，以改进现有的CFS系统的能力。麦吉尔的初步研究表明，由CFS构件和面板构成的中心护套框架体系的剪切荷载远远超过AISI S400设计的剪力荷载，延性得到了显著改善。五年研究计划的目标是：(I)开发用于中层建筑的CFS中心剪力墙体系，(Ii)扩展NBCC中列出的CFS水平地震体系(R值和高度限制)，以及(Iii)提供这些体系的设计和施工指南，以纳入AISI设计标准。方法：通过实验室试验，表征框架/护套连接的响应、框架的作用、弦杆对组合荷载的响应，以及非结构构件对抗剪和刚度的影响。完成基于有限元的剪力墙及其弦柱配置的参数研究，以扩大特征信息数据库。建立了中心围护结构的解析设计方法。使用OpenSees模型对建筑物进行动力分析，能够表示剪力墙的高强度和延性、横隔板的灵活性、非结构构件和承重墙的附加强度和刚度以及弦柱的非线性响应，以验证分析设计方法并量化所有墙体构件的贡献。通过对不同位置的建筑物模型和适用的尺度地震动套件的动力分析，开发了倾覆/抬升的设计方法，并提出了地震R值。使用脆弱性曲线来量化失败的概率。HQP：博士1人，硕士4人，研究生5人，实验室技术员5人。这一创新性研究将推动CFS框架中高层建筑抗震设计学科的发展。CFS框架结构抗震设计和分析的规范和标准将会更新。CFS框架结构在地震中倒塌的可能性将会提高，建筑物业主和居住者的安全也将得到改善。加拿大以外的学术研究项目将可以获得这些研究成果，并将其纳入全球可比设计指南中。

Cold-formed steel (CFS) framed buildings are complex systems that under earthquake ground motion excitation experience the most severe demands of their life cycle. The current CFS lateral systems described in AISI S400 are intended for use in 1 to 3 storey buildings. Given the continually increasing population in urban centres, there exists a need to develop taller & larger buildings to better optimize land use in our cities; that is, CFS framed mid-rise buildings extending up to 8 storeys in height. The force and deformation demands placed on such buildings in a design level earthquake require the development of a lateral framing system that improves upon the capability of existing CFS systems. Preliminary studies at McGill have demonstrated the potential of a centre-sheathed framing system constructed of CFS members & panels to carry shear loads far in excess of what is possible using designs from AISI S400, with substantially improved ductility.   The objectives of the 5 year research program are: (i) Develop a CFS centre-sheathed shear wall system for use in mid-rise building construction, (ii) Expand on the CFS lateral seismic systems (R-values & height limits) listed in the NBCC, and (iii) Provide guidelines covering the design & construction of these systems for inclusion in the AISI design standards.   Methodology: Characterize through laboratory testing the response of framing / sheathing connections, frame action, response of chord members to combined loading, and the impact of non-structural components on shear resistance and stiffness. Complete a FE based parametric study of the shear walls and their chord stud configurations to broaden the database of characterization information. Establish an analytical design method for the centre-sheathed walls. Institute dynamic analyses of buildings using OpenSees models, capable of representing the high strength & ductility of the shear walls, the flexibility of the diaphragms, the added strength & stiffness of the non-structural components & bearing walls & the non-linear response of the chord studs, to verify the analytical design approach and to quantify the contribution of all wall components. Develop a design method for overturning / uplift and propose seismic R-values through dynamic analyses of building models for various locations and applicable suites of scaled ground motions. Use fragility curves to quantify the probability of failure. HQP: 1 PhD, 4 Master's, 5 Ugrad students & lab technicians.   This innovative research will advance the discipline of CFS framed mid-rise building seismic design. Codes & standards will be updated for the seismic design and analysis of CFS framed structures. The likelihood of collapse of CFS framed structures during a seismic event will be improved, as will the safety of building owners & occupants. Academic research programs beyond Canada will have access to these research findings that can be incorporated in comparable design guides worldwide.