UNITED STATES POSTAL SERVICE STRUCTURAL STABILIZATION AND REHABILITATION
Clarksburg, West Virginia
Since construction of the United States Postal Service sorting facility the building had experienced ongoing differential settlement. As a result, cracks in the drywall, misaligned door frames, and cracks in the occurred within the building. To mitigate the ongoing settlement, a permeation and frac grouting program was specified as the method to stabilize the soil mass and minimize future settlements beneath the facility. Advanced Construction Techniques (ACT) was the Prequalified Grouting Contractor awarded the contract for the work.
ACT designed and fabricated Tube-a-Manchettes (TAM) or sleeve port grout pipes and utilized a custom build hydraulic jacking unit to install the sleeve port grout pipes horizontally underneath the building. The grout pipes were horizontally jacked into place from 4 access shafts located outside the facility. All sleeve-pipe were surveyed using a borehole deviation tool to determine the exact location and profile of each hole.
The access shafts were installed by ACT using a top down reinforced shotcrete construction method in which 5 feet of soil is excavated, steel reinforcement is installed and shotcrete in placed. The soils beneath the postal facility were successfully stabilized using a cementitious grout.
Electronic liquid levels were used to monitor heave/settlement throughout the duration of the work. The grouting program was monitored in real time using electronic flowmeters, electronic pressure transmitters, computers and a custom software program written by ACT. The monitoring allowed changes to the grouting program to take place in real-time. The postal facility remained fully operational without interruption to regular postal operations.