Foundations & tunnels construction

Supporting a dome in diverse soil conditions

When soil falls on bedrock, domes don’t require deep foundation systems. But because that’s the ideal rather than the norm, our engineers have become masters at creating deep foundation systems, whether than means driving steel or concrete piles down to bedrock or crafting an out-of-the-box system that doesn’t utilize pilings.

But the first step is geotechnical analysis. By examining and analyzing the desired location of the dome, engineers establish solutions that work with existing site conditions, including remediating and replacing soil as needed and compacting the ground. Once construction begins, builders prepare the site according to design assumptions, and if variations occur between the design and actual conditions, our design-build team develops alternate solutions. These steps avoid or minimize costly site-remediation work.

Once the ground is prepared, the optimal foundation system is determined, and alternative solutions often eliminate the need for deep (and expensive) foundations.

The unique and critical ring beam

With dome construction, a ring beam is added at ground level to form the foundation for the dome’s concrete and rebar. This ring beam provides exceptional rigidity that supports the load uniformly, even over irregular subsurface conditions, and provides high tolerance for settlement. At this point, all construction materials and equipment are moved inside the ring, allowing construction to continue monsoon or heat wave notwithstanding. Tunnels too are formed as needed for the material-handling processes of the dome.

Tunnels for reclaim

Depending on the configuration of the dome, the amount of material stored there, and how much product will be reclaimed an hour, the appropriate number of tunnels will be installed. Tunnels construction is determined early and is integrated into the dome’s foundation. A tunnel constructed in ground means more storage capacity within the dome, so these systems are often below grade; when water tables are unusually high, an above-grade tunnel will be constructed, though our team utilizes many strategies for working tunnels into wet soils.