Unhindered by critics who called the $114m project ‘a bridge to nowhere’, a gigantic throughway allowing animals to cross a busy freeway is close to completion
Easier to build a bridge over a freeway that already exists than to divert the freeway into a tunnel, I guess. Tunnels also require solid bedrock for structural integrity, which for all I know, this region may not have. And there may be additional risks in California with the frequency of earthquakes. But I’m not an expert, just assuming that they already weighed options and had reasons to settle on this approach.
Tunnels are even more unbelievably prohibitively expensive than this. Which makes sense, because typically one of the cheapest and most reliable ways to build a tunnel is actually pretty much the same thing they’re doing to build this bridge: cut and cover. You dig a trench where you want the tunnel to be with conventional excavation, put the road and tunnel in, then cover it back up with material over top. Here they just get to skip most of the initial excavation step, and go straight to “cover”.
Easier to build a bridge over a freeway that already exists than to divert the freeway into a tunnel, I guess. Tunnels also require solid bedrock for structural integrity, which for all I know, this region may not have. And there may be additional risks in California with the frequency of earthquakes. But I’m not an expert, just assuming that they already weighed options and had reasons to settle on this approach.
Tunnels are even more unbelievably prohibitively expensive than this. Which makes sense, because typically one of the cheapest and most reliable ways to build a tunnel is actually pretty much the same thing they’re doing to build this bridge: cut and cover. You dig a trench where you want the tunnel to be with conventional excavation, put the road and tunnel in, then cover it back up with material over top. Here they just get to skip most of the initial excavation step, and go straight to “cover”.
Tunnels are a more costly than bridges, especially if you can’t just cut and cover.
That highly depends of the terrain and whats on top of it. Urban tunnels are much more expensive indeed.