Question about assessment for liquefaction based on SPT from Fig 1813 in IBC. What percentage of points would have to fall beyond the threshold to consider that there is potential for liquefaction?
My situation:
- On our site we have two borings, within the range of the water table to the 50ft. extent of the chart we have 18 data points of which only 1 falls over the line. Our geotech generally feels that this data point can be discarded but is looking into it more.
- The neighboring site is a recent build and we have their borings as well. They have about 60 data points in the relevant range, of which 5 fall just over the line. The goetch on that job has classified it as potentially liquefiable and had them do compaction grouting.
Based on both sites it looks like somewhere between 5% to 10% could cross the threshold.
(Note that this is in an area of generally low seismicity)
The geotech will be making the call - I'd just like to be more informed about what is correct/standard.
My situation:
- On our site we have two borings, within the range of the water table to the 50ft. extent of the chart we have 18 data points of which only 1 falls over the line. Our geotech generally feels that this data point can be discarded but is looking into it more.
- The neighboring site is a recent build and we have their borings as well. They have about 60 data points in the relevant range, of which 5 fall just over the line. The goetch on that job has classified it as potentially liquefiable and had them do compaction grouting.
Based on both sites it looks like somewhere between 5% to 10% could cross the threshold.
(Note that this is in an area of generally low seismicity)
The geotech will be making the call - I'd just like to be more informed about what is correct/standard.