In the previous study, it has been clarified that stop-holes drilled at tips of crack initiated at welded toe between steel deck plate and vertical stiffener promote crack initiation between stop-holes at the upper side of deck plate. In this study, to prevent the crack initiation at the upper side of deck plate, crack initiated at weld toe of deck plate is closed by ICR treatment. Furthermore, the prevention effect on crack initiation between stop-holes at the upper side of the deck plate was clarified by bending fatigue tests and FE analysis.

From The 2011 off the Pacific coast of Tohoku Earthquake damage of RC concrete building with steel roof, a new damage has surfaced. Therefore, we were subjected to elastic-plastic response analysis of this building. Then, a new seismic retrofitting method have been proposed. As a result, when the sectional area of the roof brace is increased, the reinforcing effect is not changed even just the outer peripheral. At that time, the cross-sectional area is required about twice. In order to reduce damage to the roof joint, knee brace reinforcement is effective. This reinforcing method can reduce or omit the anchor bolts.

The purpose of this paper is to propose a seismic reinforce method for wooden house such that the 1st floor of a wooden house with insufficient seismic performance is connected by means of oil dampers to steel columns, and to disclose basic properties of seismic reinforcement effect of the method in cooperation with reinforcement of 2nd story in general method. Design procedure of the proposed seismic reinforcement method is presented and validity of the procedure is shown through design examples.

Enough studies have not been conducted up to now about the characteristic of bearings of skew bridges during earthquake. In this paper, we have conducted the monotonic loading test of the bearings by acting force in various directions, in order to evaluate non-linear property of the bearings in the respective directions. As a result, it was found out that the strength of bearings could be evaluated by the shear capacity regardless of directions. Moreover, we have conducted dynamic analyses of the steel railway bridges with different skew angles. As a result, it was found out that the bearings of the bridges with skew angles were easily damaged and the bearing at the obtuse corner was firstly damaged.

It is an urgent issue to formulate a design method for concrete filled steel tubular structures against the long duration earthquake. This report shows the results of the study and research about the cyclic rotation capacity of the square concrete filled steel tubular columns against the long period ground motion. The experimental results by previous studies and this committee are introduced and the outlines of the fatigue properties of square CFT columns subjected to the axial force and cyclic lateral loading with constant deformation are given.