Knit one, purlin two.

We’re learning a whole new vocabulary as the building rises….
A “column” is a primary, vertical beam.
A “girder” is a support beam.
A “girt” is a horizontal structure in a wall.
A “joist” is a horizontal structure that supports a ceiling, roof, or floor.
And a “purlin” is a horizontal structure in a roof.

A wall girt.

Installing a roof girder.

Close-up of roof girder installation. You can't have a fear of heights in this work!

Floor joists placed for later installation.

Mezzanine floor joists installed. The heavier beams are those below the life support system rooms.

And finally, the roof purlins!

Installing the purlins. You REALLY can't have a fear of heights! These guys are amazing. The ropes above the purlins are for safety, and all crew members wear harnesses.

Many thanks to Mike Turcotte and his crew at H & S Construction for their patience in answering my structural steel questions.  “What’s that beam called, and what’s it for?….”  Wikipedia is to thank for concise definitions.  Any errors in this post are mine!