In the previous paper, it was reported that shear fatigue fracture of welded beams was realized by experiment. The fracture occurred all in the fillet weld and an definite pure shear fatigue strength was able to accurately be clarified. But it was quite questionable, at that time, that any definite shear fatigue fracture would also occure irrespective to normal stress in combined shear and normal stress state such as γ /σ 1. In this paper, the fatigue fracture mode as fatigue strength of welded beams were investigated about the case where normal stress (σ) was larger than shear stress (γ), and it was the main pu-rpose to define a general stress criterion for fatigue fracture of welded beams. After experiment, it was concluded that the fracture due to combined effect of flexural shear and normal stresses could be certified to occure in such a welded structure, and furthermore some stress criterion might be suggested.
In this study, the corrosion resistance of type D 308 L and D 316 L weld metals was evaluated by test in boiling solution of 65% nitric acid. The experimental results are as follows. (1) Chromium is beneficial to decrease corrosion rate. Manganese and Nickel have no effect. (2) The fully austenitic weld metal has a stronger corrosion resistance than the partially ferritic weld metal as welded condition, but adverse in weld metals with sensitizing heat treatment. (3) Weld metals aged at temperature of 650 to 750°C have remarkably high rates of corrosion attack. (4) In the partially ferritic weld metal, chromium carbide (Cr 23 C 6) precipitates in the grain boundary and interior of ferrite-phase ane the carbide precipitation in the austenitic grain boundary is extremely reduced, so the corrosion resistance is improved.
There are two types in complete splice of plate girder. One type is the splice (joints of both flanges and web) at the same cross section (the straight joint). Another is joints of flanges shift some distances from it of web (the shift joint). The shift joint has been used to apply to the field weld joint of I-beam bridge. As the welding technique has been progressing, the joint strength of the good field welding has become to be never inferior to the steel plate strength in recent days, the straight joint should be adopted and welding works should be rationalized. These two types of joints were compared by welding specimens. By specimens' data, we confirmed that in case of the straight joint was adopted, defects would never take place, and the straight was adopted on the cross frame (members which connect between girders of bridge) of "Ayakawaohashi". Details of field joints and how to weld were decided by the data.Principal points in the results of this weld works are as follows: 1) Results of measurement were good and no visible deformation remained at every cross frame joints. 2) The radiograph inspection performed by sampling procedure. Disqualified parts were found only in two passages and these defects were found in early stage of this works. Welding procedures were immediately improved. It had been successful for the purpose of quality control to adopt this sampling produre. 3) Root openinge of flange and web of this works were equal but it of web should have been larger (1 mm) than flanges. 4) Numbers of labour engaged in chipping grinding (included compressor operating) to finish weld reinforoecment amounted to 13, 3% of total numbers of labour. To rationalize weld works, it ought to be remained. 5) Service plates for setting up were fit on webs, but these plates should be fit outsides of flange.