I found a section of drain missing and did not want to spend the $80+ for some new channel. So instead I designed and printed 7 sections to make up the ~1500mm of missing channel.
The photo is of a prototype testing for fitment, but gives you a rough idea of how it works.
I found I needed to install the channel together with the top grate in order to make it fit properly and it was rather tricky to get right, but once in-place with some glue it will hold up and can easily take the weight of a person standing/jumping on the grate. No idea if it would support a car, but it seems pretty strong.