500 pound bomb, what does that mean?

[snfaulkner]

What if we hired some janitors to place strategic thermite straps to the load bearing columns to be set off in a controlled way when the a bomb hits?

[Foggy]

Thank You! This helps me to understand what the reporters are talking about.

[Ravenman]

@Chronos

There really isn’t any single bomb sized appropriately for a large building target. The largest conventional bombs will destroy only a portion of a building (making them larger will mostly just destroy that portion more thoroughly), while the smallest atomic bombs will destroy much more than one building.

And my course of study in weaponeering consists of chats with actual experts in this field, so I don’t know how to level a particular building. But from looking at many pictures of buildings that have been bombed, I’m always amazed at how some seem to get obliterated while others remain standing… without walls and stuff. Where a marble building would fall on that scale of leveled/just uninhabitable and unsafe, I have no idea. But I agree with this post.

[Melbourne]

@J-P_L

Usually when they talk about the weight of bombs, I believe they are comparing to that weight of TNT (dynamite), no that it gives much information to you or me.

TNT is not dynamite. TNT was a military explosive. Dynamite was a civilian explosive. On that basis, I’d say that TNT is even harder to detonate that dynamite, and probably has a higher detonation speed, and was probably used mostly as a component of a mixed explosive.

[Tim_T-Bonham.net]

I believe the 500 pounds refers to the total weight of the bomb.

I recall a diagram in the book Danger UXB! based on the BBC television series that showed the range of German bombs & their weight, along with the nicknames given to them. I couldn’t find that actual diagram, but here are a couple of other ones.
American WWII bombs
German WWII bombs

[HurricaneDitka]

@Chronos

There really isn’t any single bomb sized appropriately for a large building target. The largest conventional bombs will destroy only a portion of a building (making them larger will mostly just destroy that portion more thoroughly), while the smallest atomic bombs will destroy much more than one building.

I haven’t been to SF City Hall, and don’t really have a good sense of how large of a building it is, but our largest conventional bombs are MASSIVE. I can’t imagine we don’t have something that would be an appropriate size.

The GBU-57A/B Massive Ordnance Penetrator (MOP) is a U.S. Air Force, precision-guided, 30,000-pound (14,000 kg) “bunker buster” bomb.

The GBU-43/B Massive Ordnance Air Blast (MOAB pronounced /ˈmoʊ.æb/, commonly known as the Mother of All Bombs) is a large-yield bomb, developed for the United States military by Albert L. Weimorts, Jr. of the Air Force Research Laboratory. At the time of development, it was touted as the most powerful non-nuclear weapon in the American arsenal. … The MOAB is not a penetrator weapon and is primarily an air burst ordnance intended for soft to medium surface targets covering extended areas and targets in a contained environment such as a deep canyon or within a cave system. … The MOAB, in contrast, has a light 2,900 lb aluminum casing surrounding 18,700 lbs of explosive Composition H-6 material.

The BLU-82B/C-130 weapon system, known under program “Commando Vault” and nicknamed “Daisy Cutter” in Vietnam and in Afghanistan for its ability to flatten a section of forest into a helicopter landing zone, is an American 15,000-pound (6,800 kg) conventional bomb, delivered from either a C-130 or an MC-130 transport aircraft. … The BLU-82 uses ammonium nitrate and aluminum (cf. ammonal).[3] The warhead contains 12,600 pounds (5,700 kg) of low-cost GSX slurry (ammonium nitrate, aluminum powder and polystyrene).

The GBU-28 is a 5,000-pound (2,268 kg) laser-guided “bunker busting” bomb produced originally by the Watervliet Arsenal, Watervliet, New York. … The initial batch of GBU-28s was built from modified 8 inch/203 mm artillery barrels (principally from deactivated M110 howitzers), but later examples are purpose-built with the BLU-113 bomb body made by National Forge of Irvine, Pennsylvania. They weigh 4,700 pounds (2132 kg) and contain 630 pounds (286 kg) of high explosive. The GBU-28 C/B version uses the 4450 pound BLU-122 bomb body, which contains AFX-757 explosive in a 3500-pound casing machined from a single piece of ES-1 Eglin steel alloy.

The Mark 84 or BLU-117 is an American general-purpose bomb, it is also the largest of the Mark 80 series of weapons. Entering service during the Vietnam War, it became a commonly used US heavy unguided bomb (due to the amount of high-explosive content packed inside) to be dropped. … The Mark 84 has a nominal weight of 2,000 lb (907.2 kg), but its actual weight varies depending on its fin, fuze options, and retardation configuration, from 1,972 to 2,083 lb (894.5 to 944.8 kg). It is a streamlined steel casing filled with 945 lb (428.6 kg) of Tritonal high explosive. The Mark 84 is capable of forming a crater 50 feet (15.2 m) wide and 36 ft (11.0 m) deep. It can penetrate up to 15 inches (381.0 mm) of metal or 11 ft (3.4 m) of concrete, depending on the height from which it is dropped, and causes lethal fragmentation to a radius of 400 yards (365.8 m).

We’ve got 30,000-lbs bombs, 20,000-lbs bombs, 15,000-lbs bombs, 5,000-lbs bombs and 2,000-lbs bombs. Something in there’s got to be the right size, or at least close enough.