MICROPILES

Historic Building Renovation - Lynchburg, Virginia

Track rig mounted down-the-hole hammer used to drill 8" diameter hole for micropiles.

Completed micropiles ready for the concrete cap.

Project required 57 Micropiles ranging in depth from 13'-31'. Micropiles consisted of 6" diameter heavy wall steel pipe embedded 5ft into competent bedrock. A number 8 rebar was placed in the center of the steel pipe and the micropile was pressure grouted with 5000 PSI neat cement grout. A pile load test was conducted with an ultimate load of 150 tons applied to the pile. Total settlement equaled .13". Design capacity of 60 tons was used for the production piles.