Construction vibrations

[BigHarvey]

As a court expert I have a case where I believe damages have been caused by construction vibrations (rock removal or micropile drilling with DTH hammer at 6 m from structure). I am looking for data about vibrations (PPV) caused by thes two construction activities. I attach a picture of the most damaged colums (sandstone with UCS of less than 25 MPa). I don't see any other explanation since loads have not changed, damages are less consequent with distance, stone is porous and weather is mild (and columns are from 1890 !). Your dataa and advice is appreciated !

 

[ANE91]

The US Mining Industry published the premiere documents on vibration damage. All other studies since somehow either try to redefine damage thresholds (e.g., museums) or restate/reframe the conclusions of the mining publications to suit the interests of the publishing authority. The bottom line is that you need an absurd amount of vibration to cause concrete to crack in such a way that the crack is visible only under 10x viewing magnification. Humans are excellent conductors of vibrations (we're full of water), so you cannot rely on accounts of "what it felt like to be in the building at the time."

The documents you're looking for are RI-8507 and RI-8896. Be careful — just because you can't explain it, doesn't mean that vibrations must be the cause. Why would vibrations crack this column but not the window behind it? You need to ask about anything that got knocked off the shelves, like plates and such. You need to look at what was happening 7m away from the structure, 8m away, 10m away, etc. If you have doubts, then have the contractor use the equipment in an open field somewhere while you are set up with a geophone to measure the PPV.