Memorandum

This memo addresses clearance required between flange splice plates and girder webs.

Field splices for steel plate and box girders shall be detailed to include welding tolerances allowed by the Bridge Welding Code AWS D1.5-2002.

3.5.1.5 Allowable lateral variation between the centerline of web and the centerline of the flange of built-up H or I members at contact surface shall not exceed 6 mm [1/4 in.].

In order to allow for this tolerance, provide a minimum gap between web and splice plate equal to the weld size plus 3/8". This also provides some tolerance for larger than specified weld sizes.

Background

A recent plate girder project had fit-up problems in the field because the web was off the flange centerline by ¼", as allowed by the welding code. Typically, flange bolt holes are drilled in the shop through only the outer splice plates (templates). This does not guarantee that the inner splice plates will fit.

If you have questions, please call Nate Brown at (360) 705-7219.

JK:dsb

RPZ/NSB