About Metal Construction

Referring still to FIGS. 1-3, a salient feature of the present invention is to provide a construction member 10 having a main body 11 which is fabricated from a high yield strength steel sheet, and which has a reduced thickness dimension in relative comparison to the steel sheets which are presently used in the fabrication of prior art construction members. Currently, the thickness dimension of the Metal Construction used to fabricate the prior art construction members have a thickness dimension of about 0.0179 inches and greater, and a yield strength of about 33 ksi. ¡°Yield strength¡± for purpose of this application, is defined in engineering and the material sciences as the stress at which a material begins to plastically (i.e., inelastically, or non-reversibly) deform. It is commonly measured in kilopounds per square inch (ksi) or megapascals (MPa). In the present invention, as the yield strength of the high strength steel sheet increases, the thickness dimension of the high strength steel sheet decreases. In one form of the invention, the high strength steel sheet has a yield strength of greater than about 57 ksi, and in another form of the invention, the yield strength lies in a range of greater than about 57 ksi to less than about 65 ksi. This allows the use of a steel sheet with a thickness dimension that lies in a range of about 0.015 inches to about 0.045 inches. Thus, if a high strength steel sheet with a yield strength of about 65 ksi is employed, the steel sheet may have a thickness of about 0.015 to about 0.030 inches. Further, where a high strength steel sheet with a yield strength of about 57 ksi is used, the steel sheet may have a thickness of about 0.030 to about 0.045 inches. The use of high strength steel sheets with these reduced thickness dimensions for the main body 11 of the construction member 10 has not been utilized heretofore with conventional stud wall applications, especially for non-load bearing walls. Moreover, the teachings of the prior art suggest that such reduced thickness sheet steel construction or framing members should only be used with a layer of solid sheet material in order to provide the requisite strength and rigidity. Thus, the prior art teaches away from the application of high strength steel sheet with reduced thicknesses in conventional stud wall applications, including those in non-load bearing walls, as is possible with the present invention.

The American Society for Testing and Materials (ASTM) published a Standard Specification for Nonstructural Steel Framing Members as Designation: C 645-00 (where ¡°00¡± indicates the year of the Standard¡¯s adoption). The C 645-00 Standard specifies a minimum thickness of 0.0179 inches before application of protective coating. Effective properties for various studs under the Standard, as calculated in accordance with the American Iron and Steel Institute (AISI) specifications, are based on a yield strength, Fy=33 ksi. The ASTM Standard does not make an express allowance for the use of high strength steel sheet, such as described above. Instead, a clear inference exists that high strength steel sheet would not meet the ASTM Standard. Based on the accepted ASTM Standard, it is thus surprising to construct a framing member using high strength steel sheet.

Further, and more surprisingly, the reduced thickness dimension of the high strength steel sheets as described above has not impaired, in any significant fashion, the use of traditional self tapping screws for attachment of wall boards or other construction members to construction member 10 . Additionally,Forging parts from an economic standpoint, the high strength reduced thickness steel sheets have not significantly increased the cost of the resulting product even though the raw material is much greater in cost pound for pound when compared with the steel used heretofore to fabricate the prior art construction member. The observations indicated, above, support a conclusion that the specific material used to fabricate construction members, and the shape, thickness and yield strengths of these materials, has never been optimized with respect to price and performance.