We can classify beams on their configuration:
Single Beams
If the structure consists of ONLY ONE long slender member to support loads, then it is a single beam. This type is the most common one, like structural girders and plank bridges, to name a few.
Depending on the configuration of supports, multiple variations of single beams exist.
Compound Beams
When a beam consists of two or more single beams, then it is a compound beam. We connect simple beams using internal connections such as hinges. A foldable balance beam used by gymnasts is one good example of a compound beam.
We must take care when positioning internal connections for compound beams. The beam should still be externally and internally stable when applied with external loads.
Summary
There are generally two types of beams: (1) single or (2) compound.
If the structure consists of only one long slender member to support loads, it is a single beam.
When a beam consists of two or more single beams connected by internal connections, it is a compound beam.
