How to weld to vintage structural steels

Structural steel has been used in buildings since the early 1900s. Many of these buildings are still in existence, particularly in New York, Philadelphia, and Chicago, and are now being repurposed, requiring rehabilitation and/or extension of the original structure. Often, these modifications require welding to the original structural members, which can present challenges regarding the weldability of these vintage steels. This article discusses the issues with welding to vintage structures, the steps involved in conducting a weldability assessment, and some recent project examples.