Transient elevated temperature tests on cold-formed steel channels with uniform heating, in Experiments on cold-formed steel lipped channels in compression at elevated temperatures

These experiments investigate the elevated temperature response of cold-formed steel lipped channels (studs) in compression. The tested studs were 600S200-54 lipped channel sections, 18 in. and 48 in. long. The studs were tested in an MTS universal testing machine and under heating from a custom-built electrical heating system. In the transient tests, the studs were first loaded in displacement control mode to achieve an axial compressive load of either 85% or 40% of the capacity. Then, the studs were heated by the electrical heating system, under constant load. The load level was maintained constant during the transient test using a force-controlled mode in the MTS machine. The six-zone electrical heating system was controlled to heat the studs at a constant heating rate and with a uniform temperature distribution, until failure. Steel temperature was measured with thermocouples. Temperature data was obtained from both the six-zone feedback heating system and manual recordings from additional thermocouple readers. The load and displacement data were obtained via the LabVIEW program. Critical temperatures, heating rates, and critical heating time are also reported. The data can be used to evaluate the fire performance of cold-formed steel members.

本实验针对冷弯型钢卷边槽型受压柱（cold-formed steel lipped channels (studs)）的受压高温响应展开研究。本次试验的试件为600S200-54型卷边槽型截面柱，长度分别为18英寸与48英寸。试验依托MTS万能试验机（MTS universal testing machine）开展，并搭配定制电加热系统实现高温加载。在瞬态试验中，首先通过位移控制模式对试件施加轴向压力，荷载分别为试件极限承载力的85%或40%；随后在维持荷载恒定的前提下，启动电加热系统对试件进行升温，试验全程通过MTS试验机的力控模式保持荷载水平稳定。该六分区电加热系统可按照设定的恒定升温速率实现均匀温度场加热，直至试件发生破坏。钢材温度通过热电偶（thermocouples）采集，温度数据可同时来自六分区反馈加热系统的输出，以及额外配备的热电偶读数器的手动记录结果。荷载与位移数据通过LabVIEW程序采集获取。本数据集同时记录了临界温度、升温速率与临界加热时长等关键参数，可用于评估冷弯型钢构件的抗火性能。