I use Cinema 4D, so the options might be slightly different, but the process should be the same. As I mentioned, 3D questions are a bit tricky on this site and usually wind up closed. I'm only answering this, because I'm on lunch break and haven't used C4D in ages, so I wanted to make sure I still had the skills.
Start with a cylinder
I then placed the cylinder into a cloner object, using the following settings
Now that you have your grate, it's time to cut the bars to a circular path. I did this by using a Boolean object, with the following settings
The hierarchy within the boole object is important, notice how mine is stacked
The cylinder on the bottom is the one that will "cut" the grate, so set its diameter to whatever you'd like
Add a Torus (use the same pipe diameter as your initial cylinder and ring radius as the cylinder you used for the boolean cutout) and voila!