e-mosty December 2017 MSS and Formwork Travellers | Page 23

This revolutionary invention was put into practice by
BERD, a company founded in 2006 in Porto, a City of
Bridges. Just over a decade has been enough time for
the company to become a model and a global leader,
carrying out projects worldwide and receiving various
prizes and awards in the sector.
1.2 OPS Description
The OPS System is mainly formed by the following
elements: the actuator in the organic anchorage, the
unbonded tendons (cables – Figure 3), and electronic
circuit.
Figure 3: Unbonded Tendon
Figure 2: A typical MSS with OPS
Organic anchorages (see Figures 3 and 4) are
anchorages
with
servo-hydraulic
systems
incorporated. That means that the hydraulic jacks
permanently stand between the anchorage and the
structure and became structural elements
themselves. The electronic circuit includes sensors,
electric cables and electronic components
(controllers), similarly to common active control
circuits.
The prestressing cables are actively controlled and
stressed progressively in the concrete-pouring stage
when the structure is loaded with the weight of the
deck fresh concrete to reduce deformation and
minimise stresses.
During the MSS launching stage (in which the MSS is
self-launched from the previously constructed span to
the next concrete pouring position), the cables are
not active and the MSS acts like a steel truss with
variable section.
← ↑Figures 4 and 5: Organic Anchorage
4/2017