In order to replace the RC deck of steel main girder, reinforcement of steel main girder is needed depending on the construction condition. In such case, the patch plates jointed by high strength bolts are generally adopted. However, structural details, such as the bolt pitch and patch plate length to achieve intended strengthening effect, are not specified. This study investigates the bolt pitch at the edge of patch plate to achieve intended strengthening effect through FE analysis considering the frictional interaction between the patch plate and the web. As a result, it was found that the reinforcing effect was increased, and the patch plate length could be shortened by narrowing the bolt pitch only at the edge of the plate.

In this study, the tensile strength characteristics of welded joints with and without corrosion are experimentally investigated by accelerated corrosion testing of specimens butt-welded with dissimilar materials of stainless steel and carbon steel. First, tensile tests were conducted on the nonexistence or existence of corrosion using butt-welded specimens of stainless steel and carbon steel of equivalent design material strength. The experimental results show that the tensile strength properties of butt-welded specimens of stainless steel and carbon steel are affected by corrosion on the carbon steel side, and that the stress concentration associated with cross-sectional defects is larger than that of specimens without corrosion damage.

This paper deals with electro-slag weld (ESW) joint of built-up box section column with TMCP steel. The objective is to clarify the effect of thickness of column skin-plate on toughness of ESW joint. Charpy impact test was carried out on ESW joints with various thickness of column skin-plate and inner diaphragm. Though charpy absorbed energy of heat affected zone (HAZ) decreases as the column skin-plate becomes thinner, the influence of thickness of column skin-plate is small when the column skin-plate is thin compared to inner diaphragm. The results of charpy impact test and heat transfer analysis showed the relationship between charpy absorbed energy and the cooling rate, and the relationship between the cooling rate and the thickness of the column skin-plate and inner diaphragm. From these relationships, the estimated value of charpy absorbed energy of HAZ was shown.

This paper investigated the influences of various structural configurations like the grip length and drilled hole shape on the stress concentrations of a non-projected and sandglass-shaped bolt comprising a countersunk head bolt and countersunk sleeve nut, which can secure a constant coating thickness and prevent corrosion. Moreover, one appropriate combination of structural configurations was explored with FEA. Obtained numerical results revealed that the nut’s drilled hole shape should be penetrating to mitigate the stress concentrations on the thread parts and fillets.