system and the reinforcement were placed in their
correct positions and prepared for the casting.
Once the arch was erected, and the provisional stay
system dismantled, the desired geometry of the pier
was achieved by filling the tubes used by the
anchorages with concrete.
2.5. Sequence of erection phases of the arch
their ends joined together with an auxiliary steel
structure. This reduced the relative movements of
both ends and allowed the placing of the
reinforcement and the preparation of the formwork.
Concrete was then poured and the auxiliary cable stay
system dismantled, removing as well the form traveler
systems of both semi-arches.
2.6. Erection of piers over the arch
The first and second segment of each semi-arch were
cast with formwork placed over the arch’s foundation.
Then, the form traveler system installed in the
hardened concrete of the first segments and the
erection cycle begun.
The form traveler was supported by segment number
n and with the formwork placed on segment number
n+1. The dimensions of the form traveler system were
changed to adjust to the segment dimensions and the
reinforcement placed. Concrete was then poured by
means of the previously mentioned cranes and some
40 hours after the concrete hardened the form
traveler system moves to the next segment where the
cycle began again.
Every 3 segments, a cable stay group was tensioned.
This was done while the reinforcement of a segment
was being placed, thus optimizing the process.
The process was ended by the casting of the middle
segment of the arch. The form traveler systems of
both semi-arches were adapted and prepared and
There are six spans over the arch. This requires 5
supports, achieved by means of four piers and the
arch key. During the arch erection process, segments
of the arch on which a pier would be placed were
prepared accordingly.
Once the arch was completed and the cable stay
system dismantled, the piers were erected with the
same means that were employed for all the piers in
the viaduct. A deformational control of the process
was undertaken to ensure the adequate behavior of
the arch.
2.7. Erection of spans over the arch
Two movable scaffolding systems were employed to
allow the symmetrical loading of the arch. They were
assembled at the abutments and moved to the spans
adjacent to the arch and then launched. The
reinforcement was then placed and the concrete
poured. Once the concrete has hardened and
prestressed, the movable scaffolding system moved
to the next span and the cycle repeated.
Fig. 6: Auxiliary structure on the key of the arch
Photo: Luis Miguel Salazar
4/2016