My neighbor's house is completely surrounded by bamboo. She planted it 30 years ago and it quickly got out of control. She now spends a considerable amount of her time during the growing season struggling to keep it in check.
As a result, I have an endless supply of bamboo at my disposal and it is tough stuff. I have used it for everything from garden stakes to lantern posts to even new shovel handles. There is no reason why you can't use it to make a bimini provided you find an effective way of assembling it. For my own part I would drill holes crosswise through the ends and use stainless bolts to connect parts
. That would also allow you to fold it, depending on the design. One thing though, you're going to want to seal the bamboo after it has dried out, if it's not already dried when you get it. Otherwise it will deteriorate relatively quickly.