Seismic retrofit with common wall

[jpspiret]

I own the end-unit of a 6-unit townhouse complex and am interested in a seismic retrofit (mainly reinforcing the cripple walls and upgrading the foundation anchor bolts). However, I share a wall with my neighbor and am concerned that my house would be bearing the brunt of the energy if he doesn't similarly stiffen his property. At the very least, I would think that there would be an increased risk of our properties separating at the common wall in the event of an earthquake. While it sounds appealing that my unit would be the only one standing, I can imagine all sorts of problems in that scenario, such as the loss of structural integrity if the common wall is missing, or if my neighbor's house bangs against mine for the duration of the earthquake.

I'm not a structural engineer, so I would appreciate any advice.

By the way; the houses were built in 1981. The mudsills are bolted to the foundation but there are no washers or bearing plates, the cripple walls are not reinforced, and the first floor is not secured to the cripple wall.

 

[vandede427]

2003 International Existing Building Code

Chapter A3: Prescriptive Provisions For Seismic Strengthening of Cripple Walls and Sill Plate Anchorage of Light, Wood-Frame Residential Buildings