EUROCODE 2 WORKED EXAMPLES - Federbeton

EC2 – worked examples 6-57
Code 90. It has be notice, however, that from stress calculation neither for the quasipermanent
combination nor in the rare one, the maximum stress results tensile. Therefore,
no specific reinforcement is required and it is sufficient to arrange the minimum amount of
reinforcing steel, able to ensure a ductile behaviour in case of corrosion of prestressing
steel.
Table of Content
Deformation
Deformation limitation is carried out to control the maximum vertical deflection for
passengers comfort. The limit values δ/L (deflection/span Length) are given by the
Eurocode 1.3 as a function of the span length and the train speed. The limit value for
maximum vertical deflection is calculated considering a span length of 27.75 m (central
span) and a train speed over 280 km/h; according to the provisions of the Code, it results:
δ
L =
1
1600
that should be multiplied by a factor 1.1 for continuous structures; finally, the following
limit may be achieved:
δlim 11 . 1
= =
L 1600 1455
As a consequence of the transient nature of this event, the elastic deflection, calculated
by the FEM model, is relative to the only live load; the check shall be performed loading
only one track, reading the maximum deflection in correspondence of the track axis.
Having loaded the right track with a LM71 load model plus dynamic allowance, placed in
the middle of the of the central span, the obtained δ/L value is:
δ effective
L
0. 0055
= =
27. 75
and it results lower than the corresponding limit.
1
5045
It can be notice that no further calculation is requested because, due to prestressing
effect, the structure remains entirely compressed, so that the elastic value, calculated by the
FEM analysis, has to be considered.
6.15.5 Verification of Ultimate Limit State
Verification at ULS should regard the structure as a whole and its component parts,
analysing the resistance of the critical regions. In addition to the analysis of ULS of
several shell element under the relevant combination of internal actions, in this example
some case of detailing are investigated, i.e.:
− bursting force at anchorage of prestressing tendon;
− spalling force at anchorage of prestressing tendon;
− punching under support plate.