X-raying Welded Steel Frame joint

[rodsika]

In other countries, steel frame are welded without x-raying the connections. Is it a requirement in the US that each joint is x-rayed to see perfect welding and is this really necessary? In steel frame building, welding is the most important factor and failure of it would lead to collapse of building in the event of even low intensity seismic activities.

 

[metengr]

You need to review the applicable design code or standard. Typically, codes and standards provide guidance for materials, fabrication, inspection and examination requirements.

 

[stanweld]

Per the AISC and AWS D1.1, each weld joint need not be radiographed.

 

[Duwe6]

Additionaly, Ultrasound - UT - is the method of choice for full-pennetration welds in structural steel under the AWS D1.1 Code. RT - radiography requires a gamma-ray source to easily penetrate structural thicknesses. Gamma RT is difficult in elevated areas not reachable by elevators or stairs, and UT is more revealing of Lack-of-Fusion defects, so I presume that those are the reasons for the historical preference for UT in the USA.

 

[gtaw]

UT has several advantages of radiography, one of which is the health hazards associated with radiography. Another is that radiography requires access to both sides of the joint.

AWS D1.1 only requires volumetric NDT when the connection is subject to certain fatigue categories and the load is tensile.

Many designers and owner require complete joint penetration groove welds loaded in tension to be volumetrically examined for peace of mind and to ensure the contractor is in compliance with the code.

Best regards - Al