There's a lot to unpack when it comes to the question of whether PVC is strong enough for dip bars. For one, PVC is a type of plastic, which means that its strength can vary depending on the manufacturing process and quality control measures used during production. Additionally, the specific grade or type of PVC can also affect its overall strength.
With that said, in general, PVC is considered to be a fairly strong material. It's often used in construction and DIY projects because it's durable and can withstand a fair amount of wear and tear. In terms of dip bars specifically, PVC would likely be able to support the weight of an average person without issue. However, if you're particularly heavy or plan on using the dip bars for intense workouts, you might want to consider a different material such as steel or aluminum.