INTRODUCTION Under the general title of "Performance of Steel-Framed Buildings and Structural Members Braced with Light-Gage Steel Diaphragms", sponsored at Cornell University by the American Iron and Steel Institute, an investigation has been proceeding in two separate but closely interrelated phases, referred to as: Subproject A - Performance of Steel-Framed Buildings Braced with Light-Gage Steel Diaphragms Subproject B - Performance of Beams and Columns Continuously-Braced with Diaphragms. The investigation now referred to as Subproject B was sponsored by the American Institute of Steel Construction from June, 1961 to June, 1963 after which A.I.S.I. assumed sponsorship with the cooperation of A.I.S.C. The summary report covering the first two years' investigation is "The Performance of Beams and Columns Continuously-Braced with Diaphragms", Third Progress Report by Fisher and Pincus, Report No.313, Department of Structural Engineering, School of Civil Engineering, Cornell University, September 1963, hereafter referred to as the Third Progress Report. Investigations to date have covered two general areas: (a) the general characteristics of shear diaphragms, with special reference to shear rigidity, and (b) the performance of diaphragm-braced columns. While a small number of additional double-column tests remain to be performed, Subproject B is essentially at the point of completion of column studies and the initiation of tests on diaphragm-braced beams. Unexpected difficulties in staffing and materials supply have resulted in some unavoidable delays, but there is considerable reason to expect that the beam studies can be substantially completed by the end of the present contract period, May 1965. This present report, to be known as the Fourth Progress Report. covers investigations for the period approximately October 1, 1963 to August 15, 1964. During this reporting period, work has progressed in three related areas: (1) improvement of understanding of diaphragm behavior, (2) inelastic behavior of diaphragm-braced columns, and (3) plans for tests on diaphragm-braced beams. Each of these will be discussed in detail in the following sections of the report. Effective shear modulus of corrugated diaphragms, as determined under Subproject B by means of double-beam assemblies (see Third Progress Report), has been correlated experimentally and, with partial success, theoretically with the shear modulus as determined under Subproject A by means of rectangular frame tests. Practically identical experimental results are obtained by both kinds of tests for small size diaphragms. In addition, the results for the large diaphragms of Subproject A have been correlated also with the small diaphragm results to a substantial degree. Cooperation between the two subprojects, therefore, has provided considerably more generality and certainty of diaphragm behavior than heretofore available. An empirical expression for the shear modulus of standard (and similar) corrugated sheets has been developed. To this end, four additional double-beam shear tests have been performed. Two additional double-column tests have been performed and a better empirical expression for prediction of failure loads of diaphragm-braced columns in the inelastic range has been developed. Planning for the projected diaphragm-braced beam phase of the program is well under way, including studies of suitable beam sections, range of beam slenderness, and details of the test setup.
Civil, Architectural and Environmental Engineering
American Iron and Steel Institute
Wei-Wen Yu Center for Cold-Formed Steel Structures
01 Aug 1964
Technical Report Number
Report No. 316
Fisher, Gordon P. and Errera, S. J., "The performance of beams and columns continuously-braced with diaphragms" (1964). CCFSS Library (1939 - present). 124.