Our friends at Deep Excavation posted about an interesting micropile case study in Northern Baltimore County for a bridge replacement project. The project consisted of 38 Micro Piles; 7†OD X 38 ft. deep including a 7 ft. rock socket, installed on a 3/1 batter, load tested to 272,000 lbs. What caught my attention is the down the hole hammer system used for installing the micropiles. The system uses a ring bit to install the casing and allow the drill string to continue beneath the bedrock elevation to construct the rock sockets. [Source: Read more about this micropile project and see additional photos at Deep Excavation. Image: Deep Excavation]
