Number of optical monitoring targets

[milkshakelake]

Is there a reference for how many optical monitoring targets are needed on a building? This isn't for a specific case, just general. But an example would be if I'm drilling soldier piles (that cause vibration) next to a 4 story building owned by a neighbor, so I need to know how many targets to put on that 4 story.

 

[MTNClimber]

One at each column is a good start. From there, I would add one for each point of interest or sensitive feature.

 

[milkshakelake]

Makes sense, thanks. I sometimes see companies doing 3-4 per building. I think doing it at every column might be overkill unless it's on a different elevation at each one.