6
J. Bujnak et al.
Fig. 3 Model of structure for interaction
300 mm deep ballast, the permissible additional stresses in continuous welded rail
on the bridge due to interaction are usually 72 N/mm
2 in compression and 92 N/mm
2
in traction.
1.1.5 Approach Banks Construction
Bridge approaches can receive sudden impact loading due to a change in the vertical
stiffness between the bridge deck and approach embankment leading to frequent
settlement of the approach bank, as indicated in Fig. 4. This may create large acceleration at high speed leading to riding discomfort. Abutments provide the vertical
support to the superstructure at the ends and connect the bridge with the approach
track. The larger backfill volumes often result in more settlement of track approaches.
Proper design of approach banks can include also provision of wider sleepers at
approaches, an approach slab or providing tapering stone to simulate gradual rise
in approach stiffness. Effective concept is similarly the use of multiple-layer strips
or fibres to reinforce the fill material perpendicular to the wall face to minimise the
large relative displacement between the abutment and its backfilled soil. Drainage
shall be suitably provided for the abutment construction, consisting of penetrable
materials, pipes and weep holes embedded in the backfill soil. The system should
Fig. 4 Approach banks arrangement
J. Bujnak et al.
Fig. 3 Model of structure for interaction
300 mm deep ballast, the permissible additional stresses in continuous welded rail
on the bridge due to interaction are usually 72 N/mm
2 in compression and 92 N/mm
2
in traction.
1.1.5 Approach Banks Construction
Bridge approaches can receive sudden impact loading due to a change in the vertical
stiffness between the bridge deck and approach embankment leading to frequent
settlement of the approach bank, as indicated in Fig. 4. This may create large acceleration at high speed leading to riding discomfort. Abutments provide the vertical
support to the superstructure at the ends and connect the bridge with the approach
track. The larger backfill volumes often result in more settlement of track approaches.
Proper design of approach banks can include also provision of wider sleepers at
approaches, an approach slab or providing tapering stone to simulate gradual rise
in approach stiffness. Effective concept is similarly the use of multiple-layer strips
or fibres to reinforce the fill material perpendicular to the wall face to minimise the
large relative displacement between the abutment and its backfilled soil. Drainage
shall be suitably provided for the abutment construction, consisting of penetrable
materials, pipes and weep holes embedded in the backfill soil. The system should
Fig. 4 Approach banks arrangement