A section of historic sewer tunnel in close proximity to a busy railway station was identified as requiring strengthening to ensure its long-term structural integrity.
Due to the disruption caused by the project and accessibility difficulties, the engineers wanted a low-maintenance solution with a 120-year design life. The structure and its bolts would also have to cope with heavy loads.
Duplex stainless steel was selected for the structure to provide excellent corrosion resistance and high strength, despite having limited dimensions due to the constraints of the tunnel section. Bolts were also needed to fix the Fiberglass Reinforced Plastic (FRP) liner panel sections to the duplex stainless frame.
The BUMAX solution
As engineers realized that conventional duplex stainless steel bolts would be unable to cope with the load requirements on the structure, they found that BUMAX was the only supplier that could offer a solution to comfortably meet the project’s demanding requirements.
“In close collaboration with the structural design engineers, we developed a solution for the main structural connections,” explains Nimeka De Silva, BUMAX Business Development Manager for the UK. “We also worked with design engineers based in Poland responsible for the design of the FRP panel sections to ultimately develop a solution to fasten the remainder of the structure to the frame, which utilized a range of different BUMAX® DX 88 bolts, to satisfy a number of different connection types over the structure.”
BUMAX delivered a solution that involved many parts on a very tight time schedule. BUMAX also provided on-site advice on bolt installation methods to ensure successful installation first time – which was essential due to the project’s timeconstraints.
The BUMAX fasteners are designed to resist the corrosive environment and high loads. The solution offers high integrity and contributes toward the designer’s requirement to achieve a 120-year design life. This ensures a cost-effective solution by minimizing maintenance and bolt replacement costs throughout the lifespan of the structure.
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