Insane that the pylons wasn't protected by artificial islands.
What would these artificial islands be made of? Sand, gravel, concrete rubble? This is a river, the constant current of the water erodes anything that resists it by staying in place. Piling up enough material to resist erosion and create a meaningful obstacle to 70000 tonnes in motion, that would significantly narrow and make shallow the navigable waterway. The only way to do this is to build giant underwater concrete towers -- basically the structures pylons typically rest on, the piers. Look up the process required to build these, it's quite an undertaking. They are engineered to withstand the pressure of ice floes every spring, they're not flimsy by any measure.
You can get a good look at the aftermath here: https://www.youtube.com/watch?v=WssFXRzRVLU
I'll be interesting to see how they choose to rebuild it.
"The new bridge is protected by 36 dolphins: four large dolphins protecting the two main pylons supporting the cable-stayed main span plus 32 smaller dolphins protecting bridge piers for 1⁄4 mi (1⁄2 km) to either side of the main span"
"The new bridge is protected by 36 dolphins: four large dolphins protecting the two main pylons supporting the cable-stayed main span plus 32 smaller dolphins protecting bridge piers for 1⁄4 mi (1⁄2 km) to either side of the main span"
For something a bit more sturdy, look at the main pylons of the Jacques Cartier bridge in Montreal [1] - these are meant to withstand annual ice rush, hundreds of tons of ice floe moving with the current of the river.
Interestingly, while the Saint Lawrence is a very active shipping channel, most shipping near the city moves through the seaway canal [2], which has solid earthen berms reinforced with concrete wherever it crosses a bridge span [3], [4] making it next to impossible for this type of accident to occur.
If memory serves right, the seaway was built to avoid the strong currents and wild rapids of the river; there are a set of locks [5] upriver, and the engineering around bridge crossings [6] seems consistent as you trace its path
1: https://www.google.com/maps/@45.5198582,-73.5385996,94a,35y,...
2: https://www.google.com/maps/@45.5237446,-73.5262812,90a,35y,...
3: https://www.google.com/maps/@45.4986758,-73.5188312,123a,35y...
4: https://www.google.com/maps/@45.4717554,-73.5051917,148a,35y...
5: https://www.google.com/maps/@45.4080264,-73.5557603,298a,35y...
6: https://www.google.com/maps/@45.4082771,-73.6528304,266a,35y...
source: https://www.youtube.com/watch?v=CwgOHpZlxvc You can clearly see there are channel barriers, its just the ship came in at an angle.