e-mosty March 2019 Long Span and Multiple Span Bridges | Page 22

The Puente Chacao project has been in
development for the past two decades. Initial
studies by the Chile Ministero de Obras Publicas
(MOP) began in the late 1990s resulting in a 1997
investment study and a technical feasibility study
in 2001. Preliminary geotechnical investigations
began in 2000. The Public Private Partnership (PPP)
procurement was terminated in June 2006, when
the consortium indicated that the bridge cost
would be greater than the financial limit imposed
by the Government of Chile. The project restarted
in 2012 when a Design Build (DB) contract was
adopted. The deck profile provides for a 600 meter-wide by
50-meter high main navigation envelope under the
north main span.
The Contract was awarded to the Consorcio
Puente Chacao (CPC) in February of 2014. The
international DB consortia members include
Brazilian company OAS, South Korean Hyundai,
French Systra and Norwegian Aas-Jakobsen. One distinctive feature of the Puente Chacao is the
use of continuous cables over three pylons to
support two main spans, which results from
unique site features.
Pylon top elevations are between +157.2 and
+198.6 meters. With the exception for the
anchorages, all major bridge elements are
supported on deep pile foundations.
Other project elements include four lane roadways
to connect the bridge to existing Route 5 sections
at both project limits; and buildings that
accommodate bridge services and a public
interpretive center.
The 2.5-kilometer-wide Chacao Channel has water
depths of up to 125 meters at the crossing
location. However, one notable exception is a rock
mass extending upward from the seafloor to nearly
sea level at Roca Remolinos (Whirlpool Rock) at
the middle of the channel.
The owner's engineering team is a joint venture of
COWI and Chilean firm RyQ. Final design began
early in 2014, and construction of portions of the
bridge pylon foundations began in early 2018. The
completed final design was accepted by MOP in
late 2018.
PROJECT ELEMENTS
ARRANGEMENT
AND
GENERAL
Results of a preliminary exploration program
indicated that the geology of Roca Remolinos
could feasibly support construction of a major
bridge foundation.
BRIDGE
Major project elements include a 2,754-meter long
suspension bridge consisting of two suspended
main spans of 1055 and 1155 meters; a 324-meter
long suspended North Side Span; a 140-meter-
long three span South Approach Viaduct; three
reinforced concrete pylons, and two main cable
anchorages.
Preliminary studies also identified that a
continuous, multi-span suspension bridge would
be more economical than a more conventional
suspension bridge design with two pylons and a
single main span. Similar studies of single and two
span cable stayed bridge alternatives reached the
same conclusion.
Figure 1: Roca Remolinos
1/2019