Properties Of Cold-formed Steel Research Articles

Flexural Behavior of Cold-Formed Steel I-section Beam under Temperature

The cold-formed steel is becoming popular in construction industry because of its various advantages and flexibility in use. The cold-formed steel is manufactured and molded in desired shape at room temperature hence there is a need to study the behavior of cold-formed steel at high temperature. Most of the research has been already done on various properties of cold-formed steel at high temperature like ductility, stress strain curve, etc. but the study on flexural strength and maximum deflection is yet to be done. Therefore in this project the properties like ultimate load, flexural strength, maximum deflection and weight change are studied at temperature up to 5500C. I-section beams were subjected to the various temperatures at 1000C, 2500C, 4000C and 5500C. After cooling the flexure tests were performed on beams in Universal Testing Machine. From the experiments it was observed that, the ultimate load and flexural strength reduces as temperature goes on increasing due deterioration in properties of cold-formed steel at high temperature, while the maximum deflection increases and there is no any weight change of cold-formed steel due to increase in temperature.

Determining elastic and shear moduli of cold-formed steel at elevated temperatures using a new sonic resonance method

An understanding of the mechanical properties of cold-formed steel (CFS) at elevated temperatures is critical for the design of CFS structures and analysis of these structures under fire; however, not much literature exists on mechanical properties at elevated temperatures. We report the measurements of elastic and shear moduli for CFS (ASTM-A1003) at elevated temperatures up to 350°C using a novel sonic resonance method. A Bode 100 network analyser was used to excite the CFS samples hanging inside a high-temperature furnace via a simple tweeter-type speaker, and for each the response signal was then detected by a Polytec OFV-5000 Laser Vibrometer Controller (Polytec Inc. Irvine, CA 92618). The resonance frequencies in both flexural and torsional modes are measured by the network analyser as a function of temperature, which allowed us to determine the elastic and the shear moduli. Both the elastic and the shear moduli decrease as the temperature increases. The results reported can be used in the CFS structure design and modelling at elevated temperatures. The new experimental methodology has been validated by a classical coupon test.