Customised and safe: four pylons formed in weekly cycles without a crane

Golden Ears Bridge, Vancouver, Canada

At intervals of 242 metres each, four bridge pylons grew steadily up to heights of 86 metres with the help of PERI ACS self-climbing technology. With a length of 970 metres, this cable-stayed bridge crosses the Fraser River and is the core element of the around 13-kilometre long six-lane highway project located near the Canadian west coast. The Golden Ears Bridge has been designed as a so-called extradosed bridge which is a cross between a girder bridge and a cable-stayed bridge. Here, the inclined cables function like a prestressing installed outside of the superstructure and are positioned at an extremely flat angle. Thus, in spite of the large spans, the pylons with a maximum height of 86 metres are much lower than a traditional cable-stayed bridge. The new route will be open to traffic in the middle of 2009 – in time for the 2010 Winter Olympic Games in Vancouver.

Customised for maximum building adjustment
The PERI formwork and scaffolding solution for the four H-shaped pylons is based on the modular-designed ACS (Automatic Climbing System) self-climbing technology and VARIO girder wall formwork. As a result, the continuously-changing pylon cross-sections could be cost-effectively and safely constructed using 4-metre concreting cycle heights and without requiring any crane support. The formwork concept takes into consideration here the continuous cross-sectional changes due to tapering on all sides. In addition, the pylon legs underneath the carriageway deck were to be constructed as double piers in a longitudinal direction, and as individual piers in the form of a composite construction with prefabricated steel cores for the upper half. In both the longitudinal and transverse directions, the pylons are haunched between 1.0 and 1.2 degrees. The cross-sections themselves change from a dispersed trapezoidal form measuring 5.26 m by 1.40 m and opening dimensions of five metres at the base to a single cross-section with external dimensions of 2.46 m by 5.00 m at the top of the pylon. For anchoring the ACS units to the pylon´s slanted edges, the PERI ACS system with its pivotable climbing shoe provided an extremely flexible system component. Through this, the ACS platforms can be fixed in position up to 15 degrees from the vertical axis.

The PERI formwork planning for the double piers took into consideration that the five-metre opening would be reduced to around four metres. Offset ACS brackets ensure that the platforms of the four different working levels could still be securely interlocked. This means that site personnel are able to move safely between both climbing units at all heights. Formwork elements for the 1.40-metre wide, inclined front ends are mounted on climbing platforms which are positioned on the longitudinal sides - the complete construction is suspended on rollers which ensures a simple and easy moving process. This means that climbing brackets are not required on the front ends and, consequently, only two climbing units are needed per individual pier. Material requirements are thus reduced and every climbing operation can be accelerated.

In weekly cycles to the top
In order to ensure efficient construction progress, PERI engineers included two separate ACS/VARIO sets of formwork, one set for the top and bottom halves of the pylon respectively. This avoids any time-consuming adjustment work having to be carried out on the climbing platforms and formwork. At the same time, on-site material requirements are kept to a minimum. Climbing has taken place every Monday: initially, the pylon legs with around four-metre concreting cycle heights in eight climbing stages up to the level of the carriageway. After the cross-member had been concreted, eleven additional climbing cycles using the second set of climbing formwork were required for the top half of the pylon.

Crane-free climbing during wind and poor weather conditions
The Golden Ears Bridge crosses the Fraser River about 30 kilometers before it flows into the Pacific. Due to the close proximity of the coastal region and the resulting higher wind speeds, the ACS climbing system was designed by PERI engineers to ensure that climbing could still take place safely even during stormy conditions with winds reaching up to 80 kilometers per hour. This is never a problem as PERI self-climbing formwork is always securely connected to the structure at all times.

VARIOKIT modular system for engineering structures
PERI´s Canadian engineers also designed efficient solutions for the approach bridges and elevations which are part of the overall project. For this, the broad PERI product range could optimally fulfil the requirements. With standardised modular construction systems, the best-suited formwork and scaffold solution has been able to be developed for each construction task. Through this, the contractor has realised time and cost advantages for the benefit of overall site operations. PERI system brackets from the VARIOKIT engineering construction kit reliably transferred concreting and live loads during construction of the carriageway slab, which included in-situ concreting, into the T-beams that were delivered and installed as partly prefabricated sections. In the process, generously-sized working widths of 2.50 metres were made available for site personnel. For the composite between the prefabricated longitudinal beams above the cross-members, PERI VARIOKIT also provided the optimal solution. Efficient construction progress and safe working conditions has been guaranteed through 600 linear metres of working platforms.

Elaborate foundation work
Soft ground and the constant risk of earthquakes made elaborate and costly foundation work necessary. The bored piles for the four pylons are up to 95 metres deep and thus longer than the visible part of the bridge piers. In those areas where the ground´s load-bearing capabilities were limited, the carriageway of the access roads and ramps rests on lightweight EPS rigid foam plastic. This so-called geofoam construction method – known through its use in dam construction technology – minimizes, on the one hand, additional loads arising from the required fill whilst, on the other, it absorbs any vibrations and shocks that may occur.

Golden Ears Crossing
The altogether 13-kilometre long "Golden Ears Crossing" infrastructure project, with an investment volume of 600 million euros, is one of the largest public-private partnership projects in Canada which Bilfinger Berger has planned, financed and built. In summer 2009, the six-lane route is to be officially opened for traffic. It will greatly relieve conditions on the main road into the city centre and considerably shorten the travelling time for commuters. The name has been taken from nearby Golden Ears Mountains. "Golden Ears" is derived from "eyries”, which refers to the eagles nests found in the mountains – for this reason, stylised eagles made of steel will be placed on the top of the pylons.

Winter Olympic Games 2010 in Vancouver
From 12th to 28th February 2010, the next Winter Olympic Games are taking place in Vancouver. The third biggest city of the North American country is located in a scenic area on the west coast of Canada in the province of British Columbia. After Montreal in 1976 and Calgary in 1988, Vancouver will be the third Canadian city to host the Games, and beat off stiff competition from cities such as Bern in Switzerland, Salzburg in Austria and Pyeong Chang in South Korea.

Contractor:
Golden Crossing Constructors Joint Venture
(Bilfinger Berger Inc. and CH2M HILL)

Field Service:
PERI Vancouver, Canada and PERI Weissenhorn

PERI Systems In Use:
- ACS R Self Climbing System
- VARIO GT 24 Girder Wall Formwork
- VARIOKIT

PERI GmbH
Editorial Office
P.O. Box 1264
89259 Weissenhorn
Germany

Phone: +49 (0) 7309.950-1180
Fax: +49 (0) 7309.951-1180
redaktion@peri.de
www.peri.de

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PERI was founded in 1969 and is today one of the leading providers of formwork and scaffolding systems. Along with the headquarters in Weißenhorn, Germany, the company has 46 international subsidiaries and 100 stock yards around the world. The company has over 5400 employees of which 850 are engineers. 2008 revenues was 1,220 million Euros.

This release was published on openPR.