I also wonder how much damage happened to the lower floor supports by transmitted vibration/pressure while the collapse was far away. We also I think are making the assumption that the floors fell as flat slabs, and that the inside part wasn't leading a bit. No way to tell that I'm aware of. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist