How can large bridges, with spans on the order of 1 km, be made resistant to earthquakes?
I'm no expert on quakes, but there are at least two kinds of shaking: lateral and vertical. The vertical shaking in particular really worries me. I don't know how any kind of shock absorbtion can be built into a massive, tall structure like a building or bridge tower.
(I was originally going to ask about suspension bridges, but then I read that suspension bridges are not great for heavy trains. The background of this question lies in my exploring the idea of a Bering Bridge (from Alaska to Siberia, crossing the Bering Strait), which would be primarily a train bridge. And it would need to handle freight trains, the heaviest of all sometimes exceeding 100 tons per car.)
So I will just ask the question about large bridges in general.
I think the largest quake in Alaska was a 9.4 Richter Scale in 1964, hitting Fairbanks. (I don't know how to convert to Moment-Magnitude scale). Is it possible to build large bridges that won't collapse from that? Ideally, we want the bridge to not collapse during a quake even if it's under full load.
P.S. I know it's not cost effective to build such a bridge. For one thing, far east Siberia has no rail network (or much civilization in general). There was a tunnel project proposed which I think they said was cheaper than a bridge, which I couldn't understand because digging through tough rock seems a lot harder than driving a pile in 50-m deep water. The tunnel project was suspended IIRC, no surprise.
Anyway, I'm just exploring if such a bridge is technically possible and can be quake-resistant. If you need something closer to reality, I suppose we can look at the Golden Gate Bridge in San Francisco. I saw here they were working to make it safe in quakes up to 8.3, but it didn't go into the details. And keep in mind the Golden Gate Bridge does not handle freight trains.
Anyway, is it possible to quake-proof or seriously resist quakes in large bridges loaded with a freight train? The bridge would not necessarily have to remain completely undamaged. I just don't want it to snap and drop the train in the ocean.
Is this possible?