Bridge Constructor Playground

Both "Big Spender" and "Monumental Structure" can be completed at the same time.

On any level, just build an overcomplicated bridge with expensive (Steel + Pillar) elements.

I can confirm there is no requirement to change the bridge on each attempt or leave the simulation screen.
Quickest way to do this is to pick Level 2 on Island 1 (Tutoria). Make two wooden bridge segments and start the simulation. Wait for the trucks/cars to enter the water, then repeat the simulation another 24 times.