I would say the damage is about the same, The ship knocked down a pier and all spans connected to the pier went down. The difference is, on the baltimore bridge is that the spans are a lot longer. But all other spans(the ones nearly out of frame) are still standing.

Parts of the Francis Scott Key Bridge not connected to the hit pylon went down too. The beam structure above the road that supports the whole thing collapsed and took down other spans.

And that structure probably existed because the bridge has fewer longer spans, probably since the seabed below the bridge is deeper (and needs to be deeper to support container ships passing below).

The Öresundsbron (connecting Sweden and Denmark) features both short segments but also with an overhand section in the middle for larger ships to pass through. (1) The great belt bridge (inside Denmark) is slightly higher but has the same kind of profile, one of the largest cruise ships barely making it under it is shown passing in the video below (2).

I think the simple truth is that we're vulnerable to these kinds of accidents unless we build far far sturdier bridges, but at these scales to allow passage of ships of these sizes the cost would just make many bridge projects prohibitably expensive.

1: https://www.norden.org/sites/default/files/styles/content_si...

2: https://www.youtube.com/watch?app=desktop&v=j1Cs0C8LkeU

The Øresundsbron is a bridge and a tunnel, and although it's not required most ships choose to cross over the tunnel rather than under the bridge.

I was curious about Zealand's other connection, the Great Belt Fixed Link:

> The West Bridge has been struck by sea traffic twice. While the link was still under construction on 14 September 1993, the ferry M/F Romsø drifted off course in bad weather and hit the West Bridge. At 19:17 on 3 March 2005, the 3,500-ton freighter MV Karen Danielsen crashed into the West Bridge 800 metres from Funen. All traffic across the bridge was halted, effectively cutting Denmark in two. The bridge was re-opened shortly after midnight, after the freighter was pulled free and inspectors had found no structural damage to the bridge.

> The East Bridge has so far been in the clear, although on 16 May 2001, the bridge was closed for 10 minutes as the Cambodian 27,000-ton bulk carrier Bella was heading straight for one of the anchorage structures. The ship was deflected by a swift response from the navy.

In Danish [2], but it looks like there's someone always monitoring the sea traffic, and able to close the bridge at very short notice — I assume with the red flashing lights which are used to close motorways in emergencies.

> The eastern end through the Great Belt is international water, and therefore even the largest ships must be able to sail under the bridge. The 254 meter high pylons are therefore dimensioned so that they should be able to withstand the approach of tankers of 250,000 tonnes dead weight (DWT) at a speed of 10 knots. Artificial islands protect the anchor blocks as well as the three outermost piers on the Zealand side and the two outermost ones on the Sprogø side.

[1] https://en.wikipedia.org/wiki/Great_Belt_Bridge

[2] https://web.archive.org/web/20090116051425/http://ing.dk/art...

Öresundsbron is claimed to be designed to be resistant against ships hitting it. They have placed artificial underwater reefs around the pylons. The pylons themselves can also take quite a beating.

The twin towers were designed to take a hit from an airliner and survive[0]. Sometimes even the best design fails when reality crashes into it.

[0] They expected fuel leaking to cause a devastating fire, but not that the fire would weaken the structure enough to cause the cascade failure that brought the towers down. https://archive.seattletimes.com/archive/?date=19930227&slug...

Sure, precautions might not work as well as intended.

But my comment was in regards to having to build a really expensive bridge to make it crash resistant. I pointed out that you can instead build a cheap flimsy bridge and put the protection in the water around the pylons.

My impression is that the Baltimore bridge had no such extra protection (?) In that case, it's not really "the best design", right?

They survived for roughly an hour after the airliners hit. That hour let roughly 40,000 people make it out.

The towers failed, in the end, but withstanding the initial hit mattered a lot.

That's great, but the topic is engineering things to survive serious damage, period. Not just long enough for people to escape before it succumbs. A failed structure is still a failed structure with all the socioeconomic trouble that entails.

You're mixing up two different things.

If the design requirement for the twin towers was "be fire resistant enough to let most people out of the building", then I'd say they met that requirement, right?

If the design requirement for a bridge is "continue operating at normal capacity", then that is a very different requirement.

"Failed" isn't the binary you're trying to make it.

Yes, the towers failed to survive serious damage. But the 40,000 more deaths would have been "socioeconomic trouble", in spades. Even by your own chosen measure, the survival for an hour was a partial success.

Maybe it's the extra momentum that took it over the edge, which if it were built in the 70s probably were designed with static loading in mind without the benefit of dynamical simulation?

Yes the entire truss section dropped. However the bridge is quite a few times longer than it's trussed section. and none of those spans dropped.

Hobart learned its lesson. You can't drive over the bridge when heavy ships sail under it.

I fell down reading about all the ships that have hit bridges, and this is probably the most practical solution for a lot of scenarios.

Yes, but Hobart is tiny so this rarely happens and relatively few people are impacted when it does.

Seems like a fair few people are going to be impacted permanently in Baltimore because of this.

"Permanently" what? the harbor will be cleared, probably sooner than later, and there will be a new bridge/tunnel built in a few years. Like that's not permanent.

The deceased and their community.

Wikipedia is missing the iconic photo of the two cars hanging over the edge of the Tasman bridge.

> "the only thing that stopped the car from tipping over the edge was the casing of the automatic transmission, which grinded and gripped into the surface of the bridge."

https://www.carsguide.com.au/oversteer/this-hq-monaros-auto-...