Field measurements at a composite bridge with composite dowels as shear connectors - Economical Bridge Solutions based on Innovative Composite Dowels and Integrated Abutments - page 65

min F D = -4.60 kN (at 1 st rail support point due to temperature induced flexion).

Forces acting on rail support point due to load scheme “Betriebszug type 5” were:

max F Z = 4.09 kN (at 4 th rail support point);
min F D = -65.5 kN (at 1 st rail support point).

Forces acting on rail support point due to load scheme “test train BR 132” were:

max F Z = 4.0 kN (at 4 th rail support point);
min F D = -36.3 kN (at 1. rail support point).

Alternatively a settlement of 3 mm was defined for the first springs on the backfill,
which means that the springs did not act for settlements not exceeding 3 mm (realistic set-
tlement). This proceeding resulted in higher forces acting on the rail support points for load
scheme “test train BR 132”:

max F Z = 6,79 kN (at 4 th rail support point);
min F D = -51,90 kN (at 1 st rail support point).

3.2 Field measurements

3.2.1 Test set-up and measurement

Wheel loads are transferred from the rail track to the superstructure by ECF rail support
points at regular intervals (“Fig. 4”). The load transfer mechanism for vertical loads F had to
be considered separately for compression and tension forces.
Compression forces are transferred from the rail through a ribbed base plate R and an
elastic intermediate layer A into the superstructure (“Fig. 7”).
The transfer of tension forces is realized by means of pre-stressed (stainless steel)
threaded bolts B which are screwed into friction welded stainless steel sleeves, anchored in
the superstructure (“Fig. 7”).

Figure 7: Load bearing mechanism of rail support point ECF (principle, superelevated

illustration), measurement equipment at rail support point ECF (principle)