LRFD and Micropile Design

The DFI / ADSC Joint Micropile Committee has formed a task force to look at how LRFD design approaches should be applied relative to Micropile Design. Currently, the vast majority of micropile designs are performed using Service Load or Allowable Stress Design in accordance with either FHWA or IBC allowable stresses. AASHTO has adopted an LRFD Design Section for micropiles as well as PennDOT. However, it is not clear how the LRFD design approach stacks up relative to current industry practice. Initial experience with the AASHTO LRFD approach would indicate that it is somewhat more conservative than Allowable Stress design and that it lacks a testing methodology that is consistent with LRFD philosophy. The committee welcomes your input on this topic in our effort to make recommendations for the best way to implement LRFD in Micropile Design and Construction.