Extraordinary earthquakes which have been predicted in recent reports may induce the dissatisfactory of seismic demand and collapse of various existing high-rise buildings caused by the strength deterioration of structural components which is not fully considered in the past research. Various weak-beam planar-models of existing high-rise steel and concrete filled steel tube (CFT) frame buildings with different stories (20F, 30F and 40F) are designed, in which, the effects of strength deterioration after the local buckling of steel and CFT components in high-rise buildings are quantitatively considered to investigate the seismic capacity of high-rise steel and CFT buildings subjected to various high-level ground motions. Results show that the amplified effects of member deterioration on the seismic responses and hysteretic energy were captured in both steel and CFT building models. However, high-rise CFT building models demonstrate better capacity than S building models to avoid the local or global collapse, when the ground motions level is extraordinary. Assessment on the collapse resistant capacity of such tall buildings by incremental dynamic analysis clearly demonstrated the significant effect of local strength deterioration on the global seismic resistant capacity of high-rise building.

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The authors have developed a buckling-restrained brace providing stable hysteretic characteristic even under high-strain condition. However, deformation about strong-axis of a core plate may adversely affect the behavior of beams, columns or connections. In this paper, the tendencies of the deformation about strong-axis of a core plate are studied as a parameter by the difference of the core plate slenderness ratios. The number of the buckling modes is calculated using the formula that has been proposed from the past study. And, the influence of the buckling modes about strong-axis on the performance evaluation is considered.

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In this paper, high-strength bolted cover plate element is used for emergency fatigue crack repair with a drilled stop-hole. For using the high-strength bolted cover plate element, it can improve the cross section and the stress distribution, so it both delaying crack reinitiating and reinforcing lost cross section from crack are possible. This is a basic study, aims at finding the influence of the high-strength bolted cover plate element arrangement for deferring fatigue crack growth more effectively. Three types of specimens are determined by the arrangement on main plate, which has a same artificial fatigue crack. Base on fatigue test result, we will discuss the influence of the arrangement for deferring fatigue crack growth, and give advice for how to use high-strength bolted cover plate element to repair crack more effectively.

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As a method of finishing weld toes for improving the fatigue strength, a bar grinder is usually employed. It is known that fatigue strength of steel members depends on stress concentration and surface roughness at the fatigue crack originating point. One of controlling factors on the stress concentration at the finished weld toes is a radius of curvature. In this study, for the purpose of investigating the effects of the curvature radius and surface roughness on the fatigue strength of out-of plane gusset welded joints with finished weld toes, fatigue tests have been performed on model specimens.

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In general, shear walls with corrugated thin steel sheets in residential cold-formed steel framing have undesirable lateral deformation capacity as a result of the buckling of the corrugated sheets or pull-out of the screws used to connect the corrugated sheets to the cold-formed steel members. The purpose of the present study is to provide corrugated shear walls with a large deformation capacity by designing "bearing-failure critical" screw joints. The validity of this design was experimentally investigated using a series of in-plane cyclic racking shear tests of the corrugated sheet shear walls. The tests showed that the local bearingfailures provide a shear wall with a stable and ductile behavior.

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