Informative 2011 FEMA Report on Nuclear Devices in Washington DC
This is a very extensive (120 page) report on the potential effects of and government response to a ground-based nuclear blast in the Capital.
https://www.hsdl.org/?view&did=702738 (It's a PDF)
The actual report is 50 pages, with several appendices that detail sheltering, building materials, decontamination, and timelines. Appendix C Has some good info on where to shelter within a given structure for maximum protection from nuclear effects (blast, radiation, fallout, etc).
I think many members here would find this information interesting and hopefully beneficial in the unlikely event of a nearby nuclear detonation.