Pull Out Test

Some of the superimposed steel structure is fixed to the welded base plates that are held by the holding down bolts . In the best case , these holding down bolts are cast in with anchorage ( e.g. fish-tail end ) and embedded into concrete . However in some cases , particularly for pre-cast concrete units , these holding down bolts are sometimes screwed into the cast-in sockets that are already embedded inside the concrete . In order to ensure these cast-in sockets can withstand the uplift force when the steel structure is imposed on , prior Pull Out Tests may be required randomly or at a sampling rate by the supervisor on site . The process of the test is to use a hydraulic jack with a dial gauge to indicate the uplift force to pull out the holding down bolt which is screwed into the testing socket until the applied force exceeds the specification requirement without signs of failure .