My hoop houses are just temporary fixes--covering seeds til they germinate, keeping bugs off seedlings, protecting from frost, keeping the chickens or other large pests away from the crops and protecting late crops from frost. I cover them with row cover, netting or plastic sheeting depending on which of the above I'm trying to accomplish. Once the job is finished I take everything down and store until needed. Most of the pvc pipe has been around for 5 years or longer--the row covering lasts about 3 if I'm careful, plastic and netting a bit longer. I build each hoop with one 10-foot length of 1/2" pvc per hoop as giving one the best flexibility in forming a good sized hoop without having it break and two 2.5' pieces to give enough height to allow one to work under it without getting a stiff neck/back.
I start with two 1/2" inch slip joints
and two 1/2" ground spikes
These are attached to the ends of the two 2.5' pieces of 1/2" pvc.
Before I connect these to the 10' piece of pvc, I slip one cross, slip-type joint for 3/4" pvc above the joint.
This will slide up the 10' piece and be used to connect two hoops together.
I then spike the ends of the hoop at 4 to 5 feet apart for a house high enough to work under--this will cover 3 rows of seeding--or 10-feet apart if I intend to cover hilled plantings like squash, cucumbers, pumpkins or potatoes(sweet or Irish). I join two or more hoops with 5-foot pieces of 3/4" pipe. You can use longer pieces but it sags and gets in the way. I suppose, since clamps can be purchased for 1" pipe, you could use this rather than the 3/4".
To steady the system I either duct tape or tie one side of the hoop to a vertical post in the ground--one at each end of the system is enough but use more if it is especially windy.
You can attach as many hoops in a series as you need.
The material is attached to the hoops and horizontal pieces using clamps sold for this purpose. I have found that these are not always reliable since they tend to lose their shape after a season or two but using a 1/2" sheet metal screw through them into the pipe will anchor them and the covering material very well.
BTW, the hoops shown are covered with netting to keep rabbits away from fall seeded lettuce, chard, carrots and spinach. I will cover them with plastic before frost and expect the veggies to be harvested up to Thanksgiving--after that it is too little light for them to grown any way and the ground will probably freeze.