The effect of extreme fire scenarios on the load-bearing capacity and durability of bridge structures
Vandalism, human error or accidents lead time and time again to fire incidents on and beneath bridges. The research project led to findings as to the consequences of extreme fire incidents. Various scenarios of a burning truck laden with wooden pallets were investigated for different types of bridge structure, as were scenarios of burning fluid escaping from a tanker.
The progress of the fire and temperature profile were calculated using computational fluid dynamics (CFD), taking account of various influencing factors, and all the relevant adiabatic surface temperature/time curves were determined. The heat penetration behaviour was then calculated using transient FEM calculation.
In the case of fires beneath bridges, the simulations indicated temperatures of the sort that occur in tunnel fires. The progress of the fire could therefore be suitably approximated by the ZTV-ING or the extended ZTV-ING curve.
In the case of fires on bridges, the temperature acting on the load-bearing structure is, on the whole, somewhat lower than in the case of fires beneath bridges. It was proposed that temperature-time curves based or factorised on the basis of the ZTV-ING curve should be used as a benchmark fire scenario.
Generalised, directly applicable benchmarking aids were developed and were used to assess the load-bearing capability of different bridges. The application of these benchmarking aids was demonstrated on various types of bridge structure.
Time frame: 01/09/2012–05/07/2013