When we were chosen to underpin the structural slab of the secure computer room in the Michigan
State Secondary Complex, we were given a list of tight restrictions beyond normal budget and
timeline requirements.
First, we needed to work inside the building. This meant bringing our excavator inside and working in a tight space while avoiding the electrical infrastructure and fire suppression lines.
Second, the computer room was operational while we were working, and computer service absolutely could not be interrupted. We faced a potential fine of $200k
per occurrence.
With these restrictions in place, we got to work. We installed 19 retrofit construction helical piles around the slab. The HP288 helical piles were installed using the E42 mini-excavator equipped with an rs7 drive head. The average depth of installation was 18’ and 6,800 ft-lbs of torque in order to achieve the specified design capacity. After installation, the piles were fitted with the retrofit bracket system, pressurized to secure the slab in place, and locked off to provide a stable, deep foundation solution in order for excavation to take place on the negative side of the piles.
After finishing the pile installation, excavation was completed for the underground utilities and flowable fill was put back in its place. Once flowable fill installation was completed, the retrofit bracket and top plate of the pile was extracted from the pile system and returned to Ayers for a partial refund as a method of value engineering. The helical lead and extensions were left in place and abandoned as construction is now complete. Despite the tight quarters and requirements of the project, we finished ahead of schedule and without any interruption to computer service
