Trains cross the railway bridge, what if there's no monitoring, and simple ways of cycle counting; would including the train's axles make correct sens !
Or counting a train as One single cycle ?
Only plausible way seems to get weekly or monthly records from railways and extrapolate the same
If the influence line of the detail is small ( 4 m e.g. ) , the detail will see every axle causing one cycle. If it is long ( 100 m ) there will be only one cycle with each train.
This question is in the eurocodes treated with the lambda-1 factor. For road bridges, the eurocodes do not provide good rules for all cases to compute this factor, but only for usual cases.
I don't know if the eurocodes are all right for railway bridges.
In the general case, the solution is to cumule the fatigue damages : For the influence lines, the calculation leads to an history of stresses. This history of stress can be treated according to EN 1993-1-9 ( normative Annex A ) with
the Rainflow counting method. For this purpose you need as M. Suresh Bhalla wrote, records of the real traffic.
Hi Aicha,
Polish railways PKP S.A. / PKP PLK S.A. , besides the TSI, has a lot of internal regulations. For example:
Id - 16 - The maintenance of railway engineering objects on railway lines to the speed of 200/250 km/h:
http://www.plk-sa.pl/files/public/user_upload/pdf/Akty_prawne_i_przepisy/Instrukcje/Wydruk/Instrukcja_utrzymania_kolejowych_obiektow_inzynieryjnych_na_liniach_kolejowych_do_predkosci_200_250_km_h_Id-16.pdf
Id-2 - Technical conditions for railway engineering facilities:
http://www.plk-sa.pl/files/public/user_upload/pdf/Akty_prawne_i_przepisy/Instrukcje/Podglad/Id-2.pdf
I also recommend:
http://www.przegladbudowlany.pl/2015/01/2015-01-PB-27-32_Grebowski.pdf
Regards,
Arkadiusz
a way to address this is through the computation of an effective stress and using the rain flow counting method. The rain flow method is a convenient way of treating a complex stress history and reducing it to a simpler accounting of a number of smaller cycles of stress that can then be converted into an equivalent constant amplitude stress. This report http://onlinepubs.trb.org/onlinepubs/shrp2/SHRP2_S2-R19B-RW-1.pdf address the use of the rain flow method for the recent calibration of the AASHTO fatigue limit states. You can do it analytically by running a series of moving loads over an influence line and tracking the stress history (via moments).
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