FTC BLOG COMMENTARY
Specification of Minimum Pile Hammer Energy
Specification of Minimum Pile Hammer Energy
We often see minimum hammer energy ratings listed in plans for piling projects. Unfortunately, it appears that most of these energy requirements were not made on the basis of WEAP (wave equation) analysis. Often the specified hammer energies are vastly lower than those needed to meet constructability requirements or to develop sufficient pile movement to fully mobilize the geotechnical resistance of a pile subject to dynamic testing (PDA).
Thermal Integrity Profiling (T.I.P.) Limitations
Due to heavy promotion by the manufacturer and other parties T.I.P. testing requirements are growing for drilled shaft projects throughout the United States. T.I.P. involves collecting temperature data generated by the heat of hydration from the curing cement in the drilled shaft concrete in attempt to identify potential anomalies in the drilled shaft installation. Such data collection is performed by using embedded wires or by using probes within temporarily dewatered CSL access tubes typically within 12 to 72 hours following concrete placement (time window depends primarily upon the shaft diameter).
Pile Requirements Review
We have seen an increasing number of piling projects that have had a host of easily avoidable piling problems. The majority of these issues were created by project designers and the owners prior to project documents being issued for bid. Such issues appear mostly to have been caused by incorrectly implementing LRFD requirements (wrong geotechnical resistance factor, pile capacity requirements that exceed the allowable structural capacity of the pile, inappropriate pile installation verification methods, etc.).