Shosuke Morino

Experimental Study of Scale Effects on the Compressive Behavior of Short Concrete-Filled Steel Tube Columns

The purpose of this research is to clarify the scale effect on the uni-axial compressive behavior of concrete-filled steel tube (CFT) short columns. Three different sizes of CFT short column specimens were tested. Other experimental parameters were the shape of the cross section, the strength of filled concrete and loading methods. Scale effects on the compressive strength of square CFT columns were observed, while those of circular CFT columns were not clearly observed.

PREDICTION OF CONVERGENT-DIVERGENT ACCUMULATION OF DISPLACEMENT AND DYNAMIC RESPONSE OF H-SHAPED STEEL BEAM-COLUMNS SUBJECTED TO HORIZONTAL TWO-DIRECTINAL GROUND MOTION

Shaking table tests of steel cantilever beam-column with H-shaped section were performed under horizontal two-directional and one-directional excitation. All specimens collapsed with the excessive accumulation of displacement u. Even though the specimen was subjected to the uniaxial ground motion, the failure mode was the lateral instability... That divergent and convergent behavior of the response was well predicted by the critical axial force for convergence of the beam-column subjected to two-directional excitation derived from the theory proposed by the author.

Elasto-Plastic Behavior of Laterally-Braced Compression Members

Elasto-plastic analysis was carried out for the behavior of compression members which had initial deflection expressed by a series of sine waves, and were braced at an arbitrary intermediate point other than the center. A parametric study on the bracing efficiency reveals that the ultimate strength could be increased by bracing, but the efficiency changes depending on the type of initial deflection and the position of the brace, and that if the designer expects the strength of a member braced at the center to be equal to the strength of the member of half length with the same initial deflection, the design bracing force may be taken equal to 2% of the ultimate strength, and the required stiffness ratio of the brace may be about 4, but it is very difficult to achieve the ideal buckling strength of a member whose effective length is equal to half the original length.

LATERAL-TORSIONAL BUCKLING OF TRUSSES WITH RECTANGULAR TUBE SECTIONS

Rigidly-jointed truss beam-columns which are composed of rectangular tubes by welding have the high strength of the lateral-torsional buckling, and can be more easily fabricated than trusses composed of circular tubes. However, the web members may cause local deformations in the flat plate elements of rectangular tube chords around the connections, which might reduce the buckling strength. From this point of view, experimental and theoretical investigations have been carried out. The paper presents the results, and then gives a more rational and economical design method instead of conventional methods which neglect the advantages of tubes.