I would like to destroy a Dyson Sphere so it leaves big junks of scrap metall with no habitable zones left. But still with enough struckture to hold Building sized blocks.

The Destruction shouldn´t be man made.

To The Sphere:
From the sun to the outer layers 


 1. Habitable Zone: cities, agricultural farms, places
 2. Support Zone: Electrics, water supply first structure level
 3. Main structure : the other structure levels where everything is build on.
 4. Spaceports and Cargo System: An infrastructure on the outside where Spaceships can be dock and a network of "Trains" transport Cargo
 5. Shield pylons: For shielding the whole Thing against little meteoroids and ships. 

I've described the hull of the sphere about 200 - 500 meters thick.

What could made such an impact on the Sphere?
How would the Destruction went on after the Initial "blow" hit the sphere?