How can existing buildings be strengthened to resist earthquakes?
Firstly, it helps to understand how buildings can be designed to resist earthquakes. A good starting point is to read : http://www.reidsteel.com/information/earthquake_resistant_building.htm. Secondly, we need to look at the typical weaknesses in many existing buildings: 1. The buildings have no structural framing; the upper floors and roof are simply built on to masonry walls. This is difficult, because some sort of framing is vital; once these walls shake a bit, the entire strength is lost and the building will collapse or pancake. The solution here can only be to strengthen each room with a 12-member cubic frame (on 4 sides round the floor, up the 4 corners of the walls, and around the 4 sides of the roof). Such frames would have to have substantial moment resistance all three ways in all 8 corners. And every room would need the treatment, especially on the lower floors. The frames should be tied in to walls, ceilings or roofs, floors as well as possible, with through bolts, or chem
