Here's the calc of destroying a skyscraper in the references to common feats: Destroying a SkyscraperEdit Mass of a Skycraper = Around 222500 tons
http://theconstructor.org/practical-guide/rate-analysis-for-reinforced-concrete/6954/
154 % = 28 % Cement
154 % = 42 % Sand (which 85 % of Sand or 35.7% of the RC)
154 % = 84 % Coarse (Granite is a good assumption)
Cement = 40454.55 Tons = 40454550 kg
Silica = 51579.55 Tons = 51579550 kg
Granite = 121363.64 Tons = 121363640 kg
Cement = 40454550/1250 = 32363.64 m^3
Silica = 51579550/2650 = 19463.9811 m^3
Granite = 121363640/2700 = 44949.4963 m^3
Fragmentation:
Low End: Using Reinforced Concrete Shear Strength:
(32363640000+19463981100+44949496300) cm^3*28 J/cc 2.7097592872e12 Joules, or 647.648013 Tons, Multi-City Block level+
High End: Using Each Material Shear Strength:
Cement = 6*32363640000 = 194181840000 J
Silica = 70*19463981100 = 1362478677000 J
Granite = 103.42*44949496300 = 4.64867691e12 J
Total Energy = 6.20533743e12 Joules, or 1.48311124 Kilotons, Small Town level
Another method:
381×129.2×57 mts = 2805836.4 m^3
90 % hollowness = 280583640000 cm^3
Fragmentation: Low End: Using Reinforced Concrete Shear Strength: 280583640000 cm^3×28 J/cm^3 = 7.85634192e12 joules or 1.87771078 Kilotons Small Town level
High End: Using Each Material Shear Strength:
Percentages of material:
154 % = 28 % Cement
154 % = 42 % Sand (which 85 % of Sand or 35.7% of the RC)
154 % = 84 % Coarse (Granite is a good assumption)
Volume:
Cement = (280583640000×28)/154 = 51015207300 cm^3
Silica = (280583640000 cm^3×35.7)/154 = 65044389300 cm^3
Granite = (280583640000 cm^3×84)/154 = 153045622000 cm^3
Frag:
Cement = 6 J/cm^3*51015207300 cm^3 = 306091243800 joules
Silica = 70 J/cm^3*65044389300 cm^3 = 4.55310725e12 joules
Granite = 103.42 J/cm^3*153045622000 cm^3 = 1.58279782e13 joules
Total Energy = 306091243800+4.55310725e12+1.58279782e13 Joules = 4.9443539 Kilotons, Small Town level+