Steel-Banded Joint Mean?
A steel-banded joint is a joint formed with an external steel band or collar located at the connection of two pipe ends. Usually used with butt joined steel pipes, steel bands fit snuggly around the pipe joint to provide leak protection and resistance to longitudinal disjointing.
A steel band is also known as a coupler.
Trenchlesspedia Explains Steel-Banded Joint
Steel-banded joints are located on the external wall of the pipe joint and can be used with or without a gasket. Visually, these joints appear as sleeves between coupling pipes and may be smooth or corrugated to provide an interlock between the band and the pipe.
Bands without gaskets provide sufficient soil tightness for dry applications. Gaskets and other elements such as rods and lugs can be added to steel banded joints to provide water-tightness for applications such as culverts and water/wastewater piping.