90-Tonne Silo Re-Levelled Following Differential Settlement

A 90-tonne stainless steel silo supported on a circular concrete ring plinth had developed a visible lean due to differential settlement beneath one side of the foundation. Surveying recorded the lowest perimeter point at approximately 36 mm below the reference level.

Investigations identified soft ground, subsurface voids and groundwater migration beneath the bunded concrete slab and silo base. The treatment area was further complicated by structural beams, deeper foundation elements, process pipework, pump equipment and live electrical services located close to the foundation.

The client required a controlled solution that could straighten the silo, fill the underlying voids, improve ground bearing capacity and reduce the potential for further settlement without dismantling the structure or undertaking extensive excavation and foundation reconstruction.

Small-diameter injection holes were drilled through the concrete slab around the circular ring plinth, with injection rods installed at depths ranging from approximately 1.5 metres to 3.5 metres. Treatment commenced at the lowest surveyed points and progressed through deeper and perimeter injection stages to improve support beneath and around the foundation.

Approximately 836 kilograms of Teretek® material was injected in controlled volumes. As the resin expanded, it filled voids, densified weaker ground and generated the lift required to correct the silo’s alignment.

Movement was continuously monitored using rotating laser and survey equipment. Injection rates and volumes were adjusted in real time to maintain a controlled lift and avoid overcorrection. CCTV monitoring was also used to protect nearby live services

At the lowest monitoring point, a total lift of 38 mm was achieved. The staged injection process restored the silo’s alignment while maintaining control over the structure’s movement throughout the works.

The treatment also filled subsurface voids, improved the bearing capacity of the supporting soils and provided additional support beneath and around the circular ring plinth foundation.

No structural distress was observed during or after treatment. The silo base and surrounding concrete slab remained intact and fit for continued operation.

The project was completed over three days, avoiding the need for extensive excavation, dismantling of the silo or major foundation reconstruction.