Geotechnical Design Services Inc.
Featured Project:
The Utah State Capitol
Base Isolation and Restoration Project
This project requires the use of nearly 3,000 micro-piles to support the entire structure at different times. Some will permanently support the center dome (designed as a composite soil/pile mat) and many others will temporarily carry the "forest of columns" in the basement while those columns are cut and base isolators are placed in the foundations. Still others will support shallow excavations within and around the basement area.
Performance requirments are very demanding, allowing no more than 3/8-inch overall differential settlement for the entire building. Installation is no less difficult, requiring most of the micro-piles to be installed in low-headroom (ten feet or less) areas. Micro-pile placement will be completed by June of '05. Load transfer operations will commence late this spring.
Full scale load test in the basement. Three micro-piles in a single cap, loaded to 600 kips were still within service limits, despite a layer of medium stiff clay in the top ten feet
Checking the grout mass around
the shoring piles (they exceeded our design specs). These piles are
being installed to support the
existing rotunda foundations while
excavations are made to grade for the installation of the final micro-pile
mats for permanent support of the
rotunda.
The "forest of columns". A driller's nightmare!!
Freshly placed micro-piles for load-transfer from the existing columns. This will be done to install base isolators within each of the existing columns. Titan hollow-bar
anchors were chosen for the entire
project, as shown here.
