3.5fabrication and erection requirements for fatigue

Longitudinal steel backing, if used, shall be continuous. If splicing of steel backing is required for long joints, the splice shall be made with a complete-joint-penetration (CJP) groove weld, ground flush to permit a tight fit. If fillet welds are used to attach left-in-place longitudinal backing, they shall be continuous.

In transverse CJP groove welded T- and corner-joints, a reinforcing fillet weld, not less than ¼ in. (6 mm) in size, shall be added at reentrant corners.

The surface roughness of thermally cut edges subjected to cyclic stress ranges, that include tension, shall not exceed 1,000 μin. (25 μm), where Surface Texture, Surface Roughness, Waviness, and Lay (ASME B46.1) is the reference standard.

User Note: AWS Surface Roughness Guide for Oxygen Cutting (AWS C4.1-77) sample 3 may be used to evaluate compliance with this requirement.

Reentrant corners at cuts, copes, and weld access holes shall form a radius not less than the prescribed radius in Table A-3.1.

For transverse butt joints in regions of tensile stress, weld tabs shall be used to provide for cascading the weld termination outside the finished joint. End dams shall not be used. Weld tabs shall be removed and the end of the weld finished flush with the edge of the member.

Fillet welds subjected to cyclic loading normal to the outstanding legs of angles, or on the outer edges of end plates, shall have end returns around the corner for a dis- tance not less than two times the weld size; the end return distance shall not exceed four times the weld size.