Theodore Levin U.S. Courthouse
Owner: US Government
Contractor: The Christman Company
Location: Detroit, MI
The renovation at the Theodore Levin U.S. Courthouse posed many obstacles that were overcome by Hardman Construction’s top notch drilling crew and management team. The primary challenges associated with this project were air quality management, the excavation and removal of 600 cubic yards of dirt and rubble from the basement, working 12 hour midnight shifts, and drilling micropiles with a Klemm 702 hydraulic drill rig with a remote power pack over 150’ from the drilling area.
Having worked in close proximity of the Theodore Levin U.S. Courthouse in the past, Hardman Construction was well aware of the potential hazard of harmful Hydrogen Sulfide (H2S) gas and Methane (CH4) entering the basement of the courthouse. These hazards along with the need to run several pieces of equipment inside the courthouse required a well thought out and properly executed air quality management plan. Thanks to the utilization of proper drilling techniques for the situation, the use of several air monitors, proper safety equipment and tier 4 rated construction equipment, Hardman Construction did not have any issues maintaining quality breathing air in the basement.
Hardman’s scope originally included only 3’ of excavation throughout the drilling area to achieve enough headroom so the Klemm drill rig could operate at full stroke. Once excavation in the basement commenced, it was clear that Hardman was going to have to do much more excavation than what was defined in the scope. After Hardman excavated 7.5’ of dirt, brick, sandstone and granite, good soil was finally exposed and the drilling area was now excavated to bottom of pile cap elevation.
All of the spoils being generated by the excavation were taken to a containment area that was located on Shelby Street where Hardman Construction was provided with 2 lanes next to the courthouse to store equipment, materials, and an area to store spoils until it could be loaded out and taken to a landfill. Coordination between court security, the construction manager, and the trucking company used to haul off spoils was always a challenge due to Hardman’s hours of operation and the requirement that all spoils quantities and type be documented.
After excavation was completed and a ramp was constructed to move the drill rig into the hole, a test pile was installed in a centralized location in the drilling area; a reaction frame was then constructed around it that only measured about 14 feet wide by 20 feet long. The load test design load for the 8-5/8” in diameter by 126.5’ long micropile was 250 kips (125 ton). Since a factor of safety of 2.0 was used, the test load on the micropile was designed to be 500 kips (250 ton). Once the load test was verified, production began in mid-March and lasted through the beginning of May. All 33 production micropiles anywhere from 126.5’ to 131.5’ long and received a full length threaded Williams center bar coupled together in 8 foot pieces. Along with the foundation piling that was installed, Hardman Construction also installed a total of 80 wall feet of micropile lagging earth retention. The primary purpose of the earth retention was to provide access to foundation pile locations that were within a few feet of an electrical duct bank running under the basement floor slab. This created a confidence inspiring drilling environment where Hardman did not have to worry about the duct bank moving or getting wet during the drilling process.
As with any significant construction project undertaking, there were many challenges associated with the job. It required an experienced crew with ample knowledge of both the drilling process and the soil conditions in the Detroit area. These factors coupled with a highly competent and knowledgeable project management team made for a very successful job that satisfied the needs of all involved parties.