The utilization of cold-shaped steel individuals in structure development started during the 1850s in both the US and England. During the 1930s, acknowledgment of cold-framed steel as a development material was as yet restricted in light of the fact that there was no sufficient structure standard and constrained data on material use in construction regulations. One of the principal reported employments of cold-framed steel as a structure material is the Virginia Baptist Hospital,built around 1925 in Lynchburg, Virginia. the floor framework was encircled with back track to back chilly shaped steel lipped channels.
冷弯型钢在结构发展中的应用始于19世纪50年代的美国和英国。在20世纪30年代，由于没有足够的结构标准和建筑法规中关于材料使用的限制性数据，冷框钢作为开发材料还受到限制。弗吉尼亚浸信会医院是冷框钢作为建筑材料的主要应用之一，建于1925年左右，位于弗吉尼亚州林奇堡(Lynchburg)。地板由背对背的冷型钢组成。（维基百科）
Design standards for hot-rolled steel were adopted in 1930s, but were not applicable to cold–formed sections because of their relatively thin steel walls which were susceptible to buckling. Cold-formed steel members maintain a constant thickness around their cross-section, whereas hot-rolled shapes typically exhibit tapering or fillets. Cold-formed steel allowed for shapes which differed greatly from the classical hot-rolled shapes. The material was easily workable; it could be deformed into many possible shapes. Even a small change in the geometry created significant changes in the strength characteristics of the section. It was necessary to establish some minimum requirements and laws to control the buckling and strength characteristics. Also it was observed that the thin walls underwent local buckling under small loads in some sections and that these elements were then capable of carrying higher loads even after local buckling of the members.
热轧钢的设计标准于20世纪30年代开始采用，但由于冷弯型钢管壁较薄，易发生屈曲，因此不适用于冷弯型钢。冷弯型钢在其横截面周围保持恒定的厚度，而热轧型钢通常表现出渐缩或圆角。冷弯型钢的形状与传统的热轧型钢有很大的不同。这种材料很容易加工;它可以变形成许多可能的形状。即使是几何形状上的一个小变化也会对截面的强度特性产生显著的影响。为了控制屈曲和强度特性，有必要建立一些最低要求和规律。此外，还观察到薄壁在小荷载作用下局部发生屈曲，这些构件在局部屈曲后仍能承受较大的荷载。（维基百科）
In the United States, the first edition of the Specification for the Design of Light Gage Steel Structural Members was published by the American Iron and Steel Institute (AISI) in 1946 (AISI, 1946).The first Allowable Stress Design (ASD) Specification was based on the research work sponsored by AISI at Cornell University under the direction of late Professor George Winter since 1939.As a result of this work, George Winter is now considered the grandfather of cold-formed steel design. The ASD Specification was subsequently revised in 1956, 1960, 1962, 1968, 1980, and 1986 to reflect the technical developments and the results of continued research at Cornell and other universities .In 1991, AISI published the first edition of the Load and Resistance Factor Design Specification developed at University of Missouri of Rolla and Washington University under the directions of Wei-Wen Yu and Theodore V. Galambos.Both ASD and LRFD Specifications were combined into a single specification in 1996 (AISI, 1996).
在美国，轻钢结构构件设计规范的第一版由美国钢铁协会(AISI)于1946年出版(AISI, 1946)。第一个允许应力设计(ASD)规范是基于AISI在康奈尔大学赞助的研究工作，在已故教授乔治温特的指导下，自1939年以来。由于这项工作，George Winter现在被认为是冷弯型钢设计的鼻祖。ASD规范随后在1956年、1960年、1962年、1968年、1980年和1986年进行了修订，以反映康奈尔大学和其他大学的技术发展和继续研究的结果。1991年，AISI在Yu Wei-Wen和Theodore V. Galambos (AISI, 1991)的指导下，出版了由罗拉密苏里大学和华盛顿大学开发的第一版荷载和阻力因子设计规范。ASD和LRFD规范在1996年被合并为一个单一的规范(AISI, 1996)。（维基百科）
In the early 1990s, as the residential construction industry ex-panded and lumber prices escalated, the steel industry recognized a new potential market for cold-formed steel applications. A Resi-dential Advisory Group was formed in 1991 to explore the ave-nues for penetrating this potential market.
上世纪90年代初，随着住宅建筑行业砂石和木材价格的上涨，钢铁行业认识到了冷弯型钢应用的一个新的潜在市场。1991年成立了一个规模咨询小组，探索进入这一潜在市场的途径。（美国钢铁协会）
通过上面的介绍，可以得知，虽然冷弯成型工艺早在上世界30年代已经出现，但是在美国，大规模系统性的转而应用到住宅类市场，是从上世界90年代开始的，而契机是砂石和木材的涨价。
目前在世界范围内，冷弯薄壁型钢结构已经能够和传统的2*4木结构分庭抗礼，占据轻型骨架结构的低层独立住宅市场的半壁江山。
虽然国内最早一批冷弯薄壁型钢建筑从业者的参与时间基本和美国同步，但是不幸的是，他们介入的时间节点砂石还没有涨价，因此基本都没挣到钱，能活下来的都是少数，不知道目前这波行情赶上没有？
从建筑的安全性角度，这个结构体系就三个力学方面的特点：一是经济截面，二是蒙皮效应，三是螺钉连接。
作为重中之重的节点连接，借用重庆大学周绪红院士的两页PPT。
建筑业是建立在法律、法规、规范、标准等一系列强制性框架之下的生产活动，每个选择都应该有依据，作为重中之重的节点连接，螺钉虽小，责任重大。
ganggouren
