Minimum throat weld thickness of tabs for longitudinal earthquake bracing?

• A. 1/8 in
• B. Equal to the pipe wall thickness
• C. 1/4 in
• D. 3/16 in

Answer: (B)

In longitudinal earthquake bracing for standpipes, the weld that attaches the tab to the pipe must be able to transfer the seismic load without becoming the weak point. The throat weld thickness is specified to be equal to the pipe wall thickness so the weld’s capacity matches the pipe’s strength. If the weld were thinner, it could shear off before the pipe and brace share the load; if it were thicker, it wouldn’t provide any additional practical benefit beyond the pipe’s own capacity. Matching the pipe wall thickness ensures adequate transfer of forces while keeping fabrication simple and consistent.