This game is a mess.
The physic are mostly wrong, especially when it comes to statics and dynamic of complex structures. The materials behave wrong, so there is no buckling of long thin steel, instead you see steel cables break from tension first.
Sometimes if you span a cable between two bearings (no load) it changes the behavior of your design (although this is mathematically not possible). Even better: when applying wind force on the described cable it broke! (This sounds like a bad joke but you can try it yourself)
The guy that made the algorythm has no no idea about structual calculations and/or the game designer didn't have common sense in noticing that there are GAMEBREAKING bugs in the simulation.
When you have to build suspension bridges, the experience is the worst (refer to the cable above), as they in general behave unbelieveable random and unrealistc - many levels you can just finish with try-retry and error and not with your knowledge about structual engineering.
At the same point this brings the only challenge you have, as the levels are boring and uninspired.
It happens regulary that your bridge collapses in one test and then you delete a part, rebuild the same part and suddenly it works. This brings us to the only good point of the game. Bridge collapse spectacular- what happens often randomly.
Ultimatly the unprecise (especially if you want to delete something) slow controls (icons spread over the whole screen) what makes retrying more frustrating than it should be.
I tried to give this game a chance, because i actually work as civil engineer - but i really got disappointed by the fake realism.