Techniques for Testing Structural Subassemblages with Braced and Unbraced Columns. Design of Laterally Unsupported Columns

摘要

Techniques and setups for testing full-size non-sway structural subassemblages with laterally braced and unbraced columns are described. The height of the sub-assemblages varied from approximately 20 to 33 feet and the width 20 to 37 feet. The columns were subjected to axial forces applied by a universal testing machine and also bending moments transmitted from the adjoining beams. These beams were loaded by two quarter-point loads through the use of gravity load simulators. Depending on the locations of the beams, the columns in the subassemblage were bent either in single curvature or in double curvature. In-plane deflections of the columns were recorded electronically while the out-of-plane deformations of the unbraced columns were recorded by means of depth gages. Electrical resistance gages were mounted on the beams and columns in a unique arrangement so as to allow various types of strains to be analyzed separately. These strains are: normal strain due to axial force, normal strain due to strong axis bending, normal strain due to weak axis bending, normal strain due to warping of section and St. Venant shearing strain. Experimental behavior and sample test results are also described. (Author)