Here are a few tips for anyone who wants to go to Viaduct Petrobras based on my lack of judgment when I went there. It’s a few years ago now but I hope it’ll be helpful anyway.
Don’t go there alone. Just. Don’t. It’s pretty much in the middle of nowhere and I had no service on my phone. If you want to get up on top of the bridge you have to climb a ladder that is loose and if you fall no one will hear you scream. If you survive the fall that is.
Make sure to have a proper car. I don’t mean your ordinary Prius or Ferrari but a 4x4 with low gears. The gravel road leading to the bridge is not the best and it’s sometimes steep.
Stay hydrated. I went there in the middle of the Brazilian summer and did not bring enough water. I don’t want to think of all the parasites I caught when I drank water from a stream I found. Bring your own water and avoid that.
I hope it helps!