Advancing the seismic performance of cold-formed steel framed building structures

易于制造，高强度重量比，尺寸精度，无限的可回收性和可重复使用性等属性，导致冷弯型钢（CFS）框架多层住宅和商业建筑的建设增加。CFS框架建筑是一种复杂的结构体系，在地震作用下，其寿命周期中的要求最为苛刻。改进的设计程序将直接提高建筑物居住者和业主的生命安全。新的北美设计标准，以解决横向负载的CFS结构的要求正在制定中。然而，现有的研究，人们可以根据新的横向荷载设计标准是有限的测试单层剪切和支撑墙下的静态或反向循环位移为基础的加载，约。20个剪力墙和支撑墙的动态试验，以及少数CFS框架隔板试验。虽然信息丰富，但现有的研究尚未纳入建筑物对地面运动的整体响应的影响，这取决于横隔板、屋顶和楼板横隔板与垂直墙的互连性以及非结构部件的存在。为了达到创新、高效和弹性建筑的下一阶段，工程师经常发现自己要对完整的3D结构系统进行建模。鉴于CFS建筑工程师目前的知识水平，他们必须对楼板和屋顶横隔、横隔和墙壁之间的连接沿着其他结构和非结构部件的建筑模型进行大量简化。简化导致i）效率低下，因为忽略了横隔板和横隔板与墙界面的影响; ii）不准确，因为横隔板传递到墙的力被近似和简化，并且横隔板本身产生的力没有得到很好的理解; iii）由于忽略了非结构部件，因此振动周期估计不正确（石膏包覆内墙和包覆外墙）通常具有与结构CFS墙相同的刚度;以及iv）过度设计，因为忽略的非结构部件具有与结构CFS墙相似的抗剪性。综上所述，这些导致v）对完整的3D CFS抗震力抵抗系统的不完全理解。研究计划的长期目标是为CFS框架系统开发经过验证的抗震设计方法。拟议研究的具体5年短期目标是：i）提供典型楼板横隔和墙力与变形滞回响应的特征，包括和不包括非结构部件; ii）设计一个数值模型，用于评估建筑物在动态地震荷载下的反应，以研究建筑物中主要结构部件（包括墙壁）的影响，隔膜（地板和屋顶），墙壁之间的连接，隔膜和非结构部件; iii）使用该数值模型进行评估，以识别和量化建筑物（横隔板/墙）对地面运动的反应; iv）建议指导方针，以准确解决CFS框架结构实际工程设计中横隔板和非结构部件的影响;以及v）在相关设计标准中包括推荐的CFS抗震设计程序; AISI S400、CSA S136和国家建筑规范。鉴于CFS的设计标准打算在整个北美使用，因此必须将与加拿大工程师有关的问题纳入设计文件;这需要加拿大各大学参与设计标准的制定。

Ease of fabrication, high strength-to-weight ratio, dimensional accuracy, infinite recyclability & reusability, among other attributes, have led to the increase in construction of cold-formed steel (CFS) framed multi-storey residential and commercial buildings. CFS framed buildings are complex systems that under earthquake excitations experience the most severe demands of their life cycle. Improved design procedures will lead to a direct enhancement of life safety for building occupants & owners. New North American design standards to address the lateral loading demands on CFS structures are being developed. However, much of the existing research on which one can base the new lateral loading design standards is limited to tests of single-storey shear & braced walls under static or reversed cyclic displacement-based loading, approx. 20 dynamic tests of shear & braced walls, and a handful of CFS framed diaphragm tests. While informative, this existing research has not incorporated the influence of a building's overall response to ground motions, which is dependent on; the diaphragms, the interconnectivity of the roof & floor diaphragms with the vertical walls and the presence of non-structural components. To reach the next phase of innovative, efficient and resilient buildings engineers often find themselves modeling the full 3D structural system. Given the current state of knowledge of CFS buildings engineers are left in the situation where they must make gross simplifications in the building models for the floor & roof diaphragms, connections between the diaphragms & walls, along with other structural & non-structural components. Simplifications that lead to i) inefficiencies, because the influence of the diaphragm & diaphragm-to-wall interface is ignored; ii) inaccuracies because the forces transmitted by the diaphragm to the walls are approximated & simplified, and the forces that develop in the diaphragms themselves are not well understood; iii) incorrect period of vibration estimates because the ignored non-structural components (gypsum sheathed interior walls & clad exterior walls) often have equivalent stiffness to the structural CFS walls; and iv) over-design because the ignored non-structural components have similar shear resistance to the structural CFS walls. Taken together these lead to v) an incomplete understanding of the full 3D CFS seismic force resisting system. The long term objective of the research program is to develop proven seismic design methods for CFS framing systems The specific 5 year short term objectives of the proposed research are: i) provide characterization of typical floor diaphragm & wall force vs. deformation hysteretic response with & without non-structural components; ii) devise a numerical model, appropriate for building response evaluation under dynamic seismic loading, to investigate the influence of the main structural components in a building including the walls, the diaphragms (floors and roofs), the connections between walls, diaphragms & non-structural components; iii) carry out evaluations using this numerical model to identify & quantify building (diaphragm/wall) response to ground motions; iv) recommend guidelines as how to accurately address the influence of diaphragms & non-structural components in the practical engineering design of CFS framed structures; and v) include the recommended CFS seismic design procedures in the relevant design standards; AISI S400, CSA S136 & the National Building Code. Given that the design standards for CFS are intended for use throughout North America it is imperative that issues relevant to Canadian engineers be incorporated within the design documents; this requires the participation of Canadian universities in design standards development.