The work we take on is varied, you have to be flexible in this economy and not say no just because you don't want to do it. This was one of those times. I didn't want to do the trench grate but I had to include it in my scope of work as part of the job.
The engineer spec'd a cast in place concrete trench with Neenah grates on top. This would have been a very labor intensive project the way it was designed. My pipe supplier suggested an alternate and we got it approved through the engineer of record.
It's a prefab'd trench grate where you dig your ditch, set the finish elevation and hang the prefab units from the form work. It went together pretty slick and I saved money on the labor end, not the material end but we were able to compete it quicker so it was a win.
The 2x4's that span the trench are bolted into the holes that hold the grates down. The grates are stacked not the pallet in the upper right hand of the pic.
If I do this again, I'll forgo the plywood forms and make a "L" bracket out of 2x6's or 2x8's to hang the forms on and let the trench cast the sides.
Poured out, I am not a concrete finisher.
We wrapped the prefab units with plastic and painters tape to keep the concrete off the grate rails.