looks nice! good work...
to make the bridge destroyable you could just use fuinc_breakable!
But I dont think that would look realistic.
there is another way to make it look better, but of course its more complicated.
so, the map doesnt look as if it was made by a noop mapper...did you work with entities like func_wall_toggle or func_breakable before?
so you could do it like that:
first you build the normal bridge with the func_breakable brush in the middle: (from above)
and then you make the parts of the broken bridge that are still in the air func_wall_toggle.
In the "target on break" field of the func_breakable you declare the name of the func_wall_toggle.
At last you have tu turn on "start invisible" in the flags of the func_wall_toggle!
Of course you have to set up the strength, so the bridge wont blow up when you fire a lil ki blast at it!
Thats it, this should work!
ps.: but then you should delete the parts of the bridge on the ground.
its not like that at all .. its not like its with a func_train or something so you don't actually see it falling it more less gets broken ( into bits ) and then the 'dammaged' parts are shown at the smame time already below
only looks bad if the finall blow is a small beam or ki blast .. http://users.pandora.be/Goes/map
i uploaded 3 newer 'finall' pics and the .bsp file itself
everything used should be defaulth files ( textures / sound )