K- Joists

This engineered steel K-joist will eventually support a metal roofing deck. Most K-joists that you see are level and straight. Below is an example of what typical k-joists look like.

These joists, in the first photo, happen to be curved to fit the shape of the roof. K-joists in general are engineered, and can support heavy loads. They take the place of a stick built wood joist system.

The joists also have other applications other than just support. If you notice, they have a distinct shape within the two main beams, a triangle. This is so that conduit and other material can be run through the beams in the ceilings.

These joists do not necessarily just come in one shape. Engineered joists come in all shapes and sizes. Some of joists have places to set HVAC units, ducts, water supply/returns, and any other material that would need to be run in the ceiling area. Below is an example of HVAC ducts run within the joists. I apologize for the blurriness.

A detail of a K joist looks as such. The top and bottom beam of the joists are called the chord, and the middle area is called the web. - where the triangles take place. This photo is from class lectures.

It is also important to know how the joist is connect to the wall. In this case, the weight of the joist bears on a steel plate that sits on top of the bond beam, which is the top course of CMU that is filled with grout to strengthen it. The photo below shows the attachment of joist to wall.