Thank you for breaking it down like this. As someone without an engineering background, your explanation (along with some Googling for terms and definitions) really helped me grasp what happened.
You got me wondering:
the whole bridge failed because the impact didn't exceed the impact strength of the bridge's material
When I first read this, it initially threw me off. The cargo ship's impact not exceeding the strength of the bridge sounds like a positive thing, but upon closer reading of your comment, it sounds as if it was the catalyst to the entire bridge collapsing.
So, how do engineers balance these properties of impact strength and tensile strength, especially considering large ships channel through these bridges near their pylons frequently? How much engineering goes into the possibility of large structures hitting their pylons?