Robotic application of high performance passive fire protection in tunnels

Abstract

Recent tunnel fires in Europe and Asia (Korea) have led to a heightened awareness of the need to consider suitable protection of tunnel users, construction fabrics and the concrete linings in high-risk locations. The significant effects of explosive spalling, and the associated heating of both the concrete and the reinforcement has led to the development of high performance fire protection measures, materials and verification. This has included the development of fire models, test methods and a range of products capable of preventing a major tunnel collapse occurring. The use of monofilament polypropylene fibres has been recognized as a possible way of mitigating the effects of explosive spalling. However, the damage due to excessive heating is not addressed with this solution. Thermal barriers, which can be used for to fully protect the reinforced concrete, are of two main types, either a spray applied cementitious-based mortar, or a pre-fabricated board, fixed to the tunnel lining. Master Builders Technology International Underground Division (UGC), part of Degussa Construction Chemicals, has developed MEYCO Fix Fireshield, a new mortar product, which has been introduced to the tunnelling market in combination with a laser guided robotic spray application system. This unique approach features a complete solution offering a passive protection system capable of dealing with tunnels of varying geometry and requiring protection from a wide range of risk profiles. The Logica application system features laser mapping for accurate profiling, computer control for accurate spraying to a tolerance of +/-5 mm and the ability to protect tunnel linings at a coverage rate of up to a 150 m2/h. With much emphasis being placed on tunnel fire protection and many funded projects currently up and running in Europe to provide guidance on fire safety in both existing and new tunnel construction, this MEYCO Fix Fireshield system offers a fast, effective and accurate method to fully protect concrete from the devastating and concentrated effects of a fire in a confined area. (A). Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.