• Experience of the specialty contractor
• Capability of the equipment
• Accurate representation of the subsurface conditions
• Proper load test and evaluation of in-situ soil friction capacity

Drilled micropiles over 50 tons capacity must undergo a pile load test. Below 50 tons, pile load tests can be waived by the engineer. Typically, drilled micropiles are tested to twice their design capacity, and the settlement at the top of the pile is measured.

Generally accepted engineering practice states that the maximum settlement of the pile shall not exceed its elastic compression, plus 0.15’, plus 1% of the pile diameter, with the net settlement less than 0.5’.

The Commonwealth of Massachusetts Building Code discusses these procedure in more detail.