Significance: Bridge pushes engineering limits, originally deemed impossible to construct.
Construction Challenges
Initial Challenges
Daunting Tasks:
Build the tallest bridge piers in the world.
Place a 36,000-ton freeway on top.
Erect seven steel pylons (700 tons each).
Faced extreme weather: landslides, winds up to 130 km/h, and storms.
Timeline
Start Date: October 2001.
Construction Goal: Complete in less than 4 years (record time).
Penalty for Delays: $30,000 a day.
Site Conditions
Geological Concerns:
Region's fractured limestone susceptible to landslides.
Critical to stabilize slopes to prevent collapse (landslide in construction phase).
Historical Context
Traffic Issues: In the 1980s, the freeway connecting Paris and Spain created a bottleneck in Milow.
Traffic Delays: Locals faced significant delays (up to 5 hours) passing through Milow.
Design Innovations
Architectural Vision
Architect: Lord Norman Foster.
Design Features:
Slimmed down peers and simplified design for aesthetic and structural integrity.
Original design called for multiple sets of cables; Foster proposed reducing this.
Engineering Approach
GPS Technology: Used for precise positioning to avoid structural misalignment.
Concrete Requirements:
200,000 tons of concrete needed with specific strength and coloration.
Complicated geometric shapes for piers required precise fabrication.
Construction Process
Piers and Deck Construction
Pier Construction:
16,000 tons of steel reinforcing bars used.
Molds changed more than 250 times to achieve required shapes.
Road Deck Fabrication:
Entire deck fabricated on solid ground for safety.
2,200 separate sections manufactured with precision (via laser technology).
Launching the Deck
Innovative Launch Method:
Used hydraulic ramps and launching systems to advance the deck without traditional methods that risked stability.
Each deck section advanced 600 mm at a time.
Wind Concerns: Wind tunnel tests conducted to analyze potential effects of high winds on the deck.
Final Phases and Opening
Deck Connection
Final Push: Two sections of the deck must meet perfectly, critical for structural integrity.
Success Rate: Decks aligned to within 1 cm during the final connection.
Public Opening: December 14, 2004, by President Jacques Chirac.
Operational Success
Traffic Levels: Peaked at over 50,000 vehicles per day after opening.
Economic Impact: Investment of $478 million recouped through tolls.
Maintenance and Challenges
Ongoing Maintenance: Regular testing of systems and structural integrity required due to the bridge's design and height.
Tourist Destination: Attracted 700,000 visitors in the first 9 months, creating new challenges for management (e.g., safety incidents).
Conclusion
The Milow Viaduct stands as an iconic achievement in modern engineering, combining aesthetic beauty with groundbreaking structural design, achieving heights never before reached in bridge construction.