CONCRETE SILO EXTERIOR REPAIR

Two concrete silos in a chemicals facility were experiencing a developing concrete failure that resulted in water leakage and structural integrity issues. Industrial Access was contracted to inspect the roof and wall exterior of the silos and address the deterioration of concrete walls as well as roof railing systems. Both silos were repaired and returned to a safe operating condition with restored structural integrity.

A chemicals plant in the southern US was looking for a contractor to engineer, design and construct a solution to repair the roofs and concrete walls of two concrete silos, 150’ high and 40’ in diameter each. Industrial Access (IA) was selected to visit and document the existing condition of the silos and address the issues of water intrusion, concrete spalling, and compromised roof safety and integrity. IA inspected the upper sections and railing systems of both silos, and preformed concrete repair upon agreement with the client.

Technicians at IA are experts in providing rigging, rope access and unique access solutions for industrial work at height, so the inspection was carried out utilizing rope access techniques. Concrete repairs were performed using an exterior scaffolding system installed across the circumference of each silo. This allowed to safely and efficiently access the upper sections of silos for concrete restoration work. The safety rail systems were easily accessed via the rooftop.

IA team first addressed the gap between the silo roof slabs and the exterior concrete walls. They removed existing failing seal between the roofs and the walls to prepare for the application of a new sealant as well as a weather-proofing coating to the upper 10’ of each silo. Exposed rebars in the roof slabs were primed, protected and patched up.

In areas of larger concrete cavities in the exterior walls, IA performed silo wall and its reinforcement protection and restoration by first scoring the concrete at least 4” outside the areas of spalling. The crew cut vertical and horizontal grid lines inside the perimeters at minimum thickness of 0.5”. Then the compromised concrete was chipped off to expose steel rebars and beams. Any loose material was removed and the surface was cleaned and prepped for bonding primer application. The bonding primer used was a cementitious epoxy resin designed to provide corrosion resistance to the steel reinforcement. Once primed, new mortar was installed to restore the integrity of the concrete walls.

In order to repair existing cracks, the cracks were first widened and raked out to increase the surface areas to a depth where solid concrete is encountered. The cracks were then sealed using an epoxy repair adhesive. Concrete repair was concluded by pressure-washing the surfaces and applying a corrosion resistant coating system.

IA also performed guardrail repairs on the roofs. Corroded areas of the guardrails and toe boards were first cut out, mainly the bottom of the guardrail posts. Then, new sections were spliced in and the guardrail posts were properly anchored to the concrete slab to ensure the safety of the silo rail system. Additional steel plates welded in place to keep the guardrails secure. Any cracks found in the rails were welded shut.

All of the repairs were completed successfully and on time. Repair work on the silos’ exteriors in addition to the guardrail repairs will ensure the longevity of both structures and maximize their operational efficiency. Silo roofs and walls should be regularly examined to ensure no cracking is present, otherwise moisture penetration will corrode steel reinforcement and interior components, which eventually can lead to a more severe structural failure. Naturally, wear-and-tear is inevitable, but IA is always available to provide timely inspections and effective repair solutions to industrial facilities and their structures.