Abstract: A pile bearing capacity determination system which allows the pile driver operator to determine the bearing capacity of a pile while it is being driven without interrupting the driving operation to perform a dead load test. Force sensors are cast in the pile at the head, toe and mid-portion and also an acceleration sensor is cast in the head of the pile. An ultra-fast sensor produces a detailed profile of the force exerted by each hammer blow on the pile. The hammer force at which the pile breaks loose from surrounding soil and begins to move during a hammer blow correlates quite well with bearing capacity of the pile determined by dead load tests. Points on the acceleration curve help verify transition points on the force profile. The force and acceleration curves are indicated simultaneously on an oscilloscope and plotter.