Ben Kato

Rotation capacity of H-section members as determined by local buckling

Abstract Inelastic rotation capacities of H-shaped steel members subject to various types of loading are investigated. By combining the simplified moment versus rotation relationship with the statistical critical stress of stub-columns, the rotation capacities are predicted and they are compared with test results. The width-to-thickness ratio limitation of flange and web are presented in a form of interaction according to the ductility requirements.

Effects of joint-panel shear deformation on frames

Abstract The strength and shear deformation of joint-panels of beam-to-column connections of steel rigid frames subjected to horizontal loading are discussed. The effect of strength and deformation characteristics of joint-panels on the load-carrying capacity and ductility of the rigid frame is assessed in elastic and inelastic regions.

Standardized mathematical expression for stress-strain relations of structural steel under monotonic and uniaxial tension loading

SummaryTension tests on 36 specimens of steel plates produced in Japan are carried out according to the testing method proposed by RILEM TC 83. The stress-strain curves obtained from the tests are mathematically expressed by determining the material constants included in a modified Menegotto-Pinto model. These results give standardized stress-strain relations with respect to SS41 and SM50A steels generally used in Japan as structural steels for building structures. These kinds of data are expected to be accumulated by many countries and should be then compared internationally to establish a more reasonable stress-strain relationship usable for structural analyses.

Statistical features of mechanical properties of current Japanese steels

As part of the work of RILEM T/C83-CUS, a statistical survey on mechanical properties of recent Japanese steels was performed on the basis of mill sheet data collected from six major mill makers of Japan. As a major result, wide scatter bands of yield point strength were found; this caused higher yield ratios of supplied steels than those based on the specified lower limits of yield strength and tensile strength. A high yield ratio is not preferable for ductility design of steel yield strength and tensile strength. A high yield ratio is not preferable for ductility design of steel structures. Thus, the upper limit of yield strength or yield ratio should be specified for such design use.

The equilibrium of short strain-hardening steel columns

Abstract The post buckling behavior of short, centrally loaded, structural steel columns subjected to monotonically increasing axial deformation is predicted analytically using a simplified Shanley model and the numerical results obtained are compared with experimental data. Because of the presence of the plastic flow and strain-hardening regions in the stress-strain relation, this behavior is very complex. It is shown that columns having slenderness ratios less than a certain critical value can, after buckling laterally a limited amount, actually return to their straight position prior to buckling to complete failure.

Design rules for connections in Japan

Design rules for structural joints and connections in Japan are outlined. They are specified for both serviceability limit states and ultimate limit states. A commentary on their application is given.

SHEAR STRENGTHS OF CONCRETE FILLED STEEL BOX ELEMENTS

This study evaluated the ultimate strengths as well as the effect of the ultimate composite actions of concrete-filled steel composites under combined bending, shear, and axial forces. Efficiency against bending of these composites is due to the flange action of the peripheral steel plates. Such efficiency can be expected against shear that the steel periphery and in-filled concrete interact as if they were diagonal tension and compression members in truss frameworks, respectively.

Study of Welded Defects by Ultrasonic Spectrum Analyser

Generally there are 5 sorts of internal defects of weld, namely blow-hole, slag-inclusion, lack of fusion, incomplete penetration and crack; but under existing circumstances, it is difficult to classify these defects by ultrasonic echo-pulse testing. For the purpose of studying to classify welded defects by ultrasonic spectrum analysis, at the outset, we attempted to distinguish crack from the other defects. We searched for each associated ultrasonic spectrum connected with NDI-STB-A2-4 mmφ hole, NDI-STB-Al (I.I.W. type)-1.5 mmΦ hole, incomplete penetration, crack and fractured surface by calculation and ultrasonic spectrum analyser.As the associated ultrasonic spectrum of crack has great roughness as compared with those of the other defects, crack can be distinguished from the other defects by associated ultrasonic spectrum.

Low Cycle Bending Fatigue Test of Steel Plates with and without Welded Joint

This paper reports the result of low cycle fatigue test. The laod of this test was given by pure bending shown in Fig. 4, and the amplitude of moment was constant. The specimens consist of two kinds. One is butt-welded in centre part of the plate as shown in Fig. 2, and the other is base metal. Variations of steel classfication are four: SM41, SM50, SM50Y, and SM53.The results of this test are summarized in Table 3. It was ascertained by this test that fatigue life in low cycle fatigue range is influenced by tensile strength more than by yield stress of coupon test, and that fatigue strength of welded specimens is as high as that of base metal if welding is good.The trait of crack propagation was distinguished in two types.(a) propagation in weld metal zone(b) propagation in heat-affected zoneIt was observed in this test that (b) type was more preralent than (a) type.