Well, if they can do it once, they probably could do it another time, but on the other hand, I don't see how Russia is fixing that bridge in a manner it would matter.
That bridge is out, and will be out for a long time, losing a chunk like that you can't just lay across it, you will need to replace that slab completely, and that job would have taken months in peace time, not when you are under missile or IED threat.
You can't bring down a whole section of a bridge with a tiny explosion and trunk loaded with grenade. A bridge was build with concrete, that can take a lot of blast. The way that bridge come down, judging by the photo is the section of that slab got completely removed from the brace that joint the 2 sections together, meaning that explosion had lifted the bridge up, rock it away and make the entire slab come back down not "re-sitting" back into the brace. It took a very big blast to move an entrie concrete slab like that. It's not some small explosion.