500N, not that I am aware of. However I had seen a training film of the 60s that showed the stength of the Victorian terrace houses and shops and their potential for surviving levels of nuclear blast.
The main strength of the shop was the iron columns supporting the upper floors. The strength of the house lay in the bedroom floor construction. In both cases the frint could be blown out but the building would hold together. Obviously this only applied to blast and not to a direct hit.