Working with bamboo

I am wondering if anyone has worked with split bamboo that appears to be warped. We have a 5" piece that we had cut in half before shipping. It is to be fitted against a wall, one on each side of the bar. Whether the cut is crooked or the pieces are warped, I am not sure, but we want it to lay flat against the wall. For now we are laying them on the floor with weight to try to flatten the edges against the floor. Does anyone know the best method for straightening bamboo?
Thanks,
Deirdre

When you nail it to the wall it will flatten it.

The first time I was at Oceaniac Arts, I was standing next to a huge pile of timber bamboo and a bang shot so loud, I was temped to go home and change my pants, the fellow there explained that when a "chamber" cracks open it often bangs like that. The bigger and older the bigger the boom! I have "relieved" the back side of the bamboo by cutting some shallow grooves length wise, inside. This allows it to flex a bit.

I had a whole car load of 5 and 2 inch bamboo coming back from Hale Tiki and in the cold night air, it was popping the whole way. LOUD and sometimes you could hear stuff flying. And the whole time in Hale Tiki it was popping. I wonder how many weeks it continued?