The Comparative Study of the Straight-Joint with the Shift-Joint in the Complete Splice of the Plategirder (Report I)

The Field Welding of the Cross Frame Joint

Abstract

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.