A pergola is a flat top structure that can act an arbor to support plants. Sometimes used as shade or for decoration. I decided to build one out of steel as I like the narrow lines and like to weld. I am pretty well over that now... It took a bit longer than I anticipated....
I noticed several of the pics have brands showing. These are not intended as recommendation of any particular brand or source.
Step 1: Design, Materials, Tools
I settled on the design in the picture. It was design #5 of 5.. The dimensions of the top are 10' x 10' as steel comes in 20' lengths, and the area I was going to place the pergola called for about that size. Height was still a variable, so I ordered enough steel for eight 10' legs (2 per corner). I also decided to do the whole thing with 1"x2" box.
I went with .065 inch steel as I didn't really need lots of strength, and it cost 1/2 as much( as 1/8th), but it was more difficult to weld and is a bit more fragile and prone to burn through when welding in the breeze outside. The final structure is very strong - easily supports me.
Step 2: The Top
This is the assembly of the top flat design of the pergola - squares inside squares. Assembly of this section was the easy part as I could work at ground level.
Step 3: Place and Level
This was definitely the biggest structureI had tried to weld. The upper pattern flat part was easy, but I decided i could not pre-attach the legs then move it without fear of tumbling disaster. My solution was to build a temporary wood scaffold to hold the top both level and in position, then attach the legs in place. Not sure it was the best solution, but it did work.
Step 4: Legging
Attach the legs, make sure they are vertical, and anchor them.
Step 5: Finishing the structure and welds
I decided to add little cross braces - looks and strength. Then cleaned up all my welds on the tops of legs.