Technical aspects and innovation

The Bridge’s basic structure is made up of four iron towers each 61 metres high, raised in pairs on both sides of Bilbao’s river and which constitute the Bridge’s pillars, linked between them by a 160 metre long crossbeam situated 45 metres above the high tide level.
The structure is entirely pieced together with sheet iron parts joined together by red hot rivets given that the welding techniques at the time the Bridge was built were not very advanced. In order to fix the structure, the Bridge uses 8 iron support cables (4 on each side) anchored in foundation blocks situated on both sides of the Bridge (in Portugalete and in Getxo),110 metres away from the towers. Furthermore, the structure’s towers are braced perpendicularly to the crossbeam by iron cables anchored in the quays which run parallel to the river, about 60 metres away.

The upper horizontal crossbeam, from which the gondola hangs, “rests” between the towers by 70 steel cables called suspension cables. It is not in fact welded or riveted to the towers or pillars, but is in fact only held by these suspension cables which support a large part of the weight, and supported in the corbels, a type of capitals next to the towers which help to resist the weight of the deck in a balanced manner. This is where it gets the nickname hanging as the crossbeam really hangs between the towers, although many associate it with the suspension of the gondola.
The transport of vehicles and passenger is done by a gondola, which hangs from a cart with 36 wheels and 25 metres long and which moves along the rails in the horizontal crossbeam. The current cart is from 1999 and gas twelve electrical motors (the original used a traction system via cables and pulleys which worked thanks to a steam boiler situated in one of the Bridge’s towers). The current gondola dates back to 1999 and is the fifth in the Bridge’s history. The control panel is situated on the ground floor of one of the towers in Portugalete, to ensure proper vision.

The current duration of the trip between the two sides of the river is one and a half minutes; the shuttle runs every eight minutes.
The gondola has capacity for 6 cars and 200 passengers (100 in each room), and it can also take 6 motorbikes or bicycles.
The footbridges have been prepared for tourists, as well as two panoramic lifts, one on each side of the Bridge, which are accessed via the terraces.
The Vizcaya Bridge was the first shuttle bridge built in the world, but its technological originality is not only due to the development and operation of a shuttle mechanism (gondola, cart and rail) but also due to its spectacular iron structure and the use of steel cables which fix the structure.

Innovation in the Bridge

The company which took over the concession in 1995 was clear right from the beginning that significant changes had to be introduced in the operation of the concession to enable it to continue providing the service and continue conserving the monument.

First generation

At the beginning the innovation was orientated towards the technology:

  • The existing gondola was substituted for another more in line with the technological progress.
  • Innovative boarding halls were constructed with automatic systems.
  • The payment systems were unified, eliminating the personal ticket offices and installing self-payment systems.
  • The entire installation is automated via the control room.
  • Oriented towards the market, opening new business lines and boosting the touristic aspects:
  • Panoramic terraces were installed above the boarding halls.
  • Souvenir and convenience stores were opened.
  • Panoramic lifts were placed in the pillars of the towers in order to access the pedestrian footbridge.
  • Complementary activities were developed consisting of third parties commercially using spaces for advertising and technical purposes.
Second Generation
Chronology of the construction

and the subsequent modifications to the Vizcaya Bridge

1887 Preparation of the draft project for a suspension bridge with a mobile vehicle adapted to large estuaries, in secret conversations between Alberto Palacio and Ferdinand Arnodin.

1887 November 5. Simultaneous presentation of the invention patent application by Alberto Palacio, in Bilbao, and Ferdinand Arnodin, in París.

1888 February 20. Presentation of the Vizcaya Bridge construction project.

1890 February 12. Concession of the licence to build the bridge between Portugalete and Getxo, after overcoming the technical reluctance of the engineers from the Ministry for Promotion’s Public Works Department.

1890 April 7. Constitution of the company “Martín Alberto Palacio y Compañía” with the aim of constructing and operating the Bridge.

1890 May to 1893 July. Construction of the Vizcaya Bridge, with Alberto Palacio as works director, Ferninand Arnodin as constructor and with the technical assistance of the engineer A. Brull.

The pillars are made of profiles forged in Le Creusot. The replaceable cables are of mild steel from the Firminy wireworks. The wiring by the workshops of Ferdinand Arnodin in Chateauneuf-sur-Loire. The deck is made up of a beam with Saint Andrew crosses made of mild steel by the Altos Hornos de Vizcaya blast furnace rolling mill, Assembled at the Zorroza workshops in Bilbao. The suspension of the beam is mixed, using vertical suspension cables and inclined shrouds. The energy supplied by a two cylinder vertical steam boiler with water pump, produced by Henri David in Orleans, moves the cables which pull the gondola. The motor system is placed in a large hut placed between the two towers on the Getxo side.

The original conception by Alberto Palacio to obtain the movement was a cart moved by compressed air (Mekarsky system).

1894 The company is concerned about the complication of a steam boiler situated high up and the services for its operation.

1901 An electric motor is installed to replace the boiler in the same place. The lift which was not able to be installed before due to the lack of electric supply is installed in Tower 2. The stairs are passed to Tower 1.

1937 June 16. Members of the Military Engineers Corps made controlled explosions of the parabolic bases of the Vizcaya Bridge on the Getxo side to make it temporarily useless for the enemy forces, and not to destroy it completely.

1939-1941 Reconstruction of the Vizcaya Bridge, with the project by the engineer José Juan Aracil, works management by Luis Alberto Ribed and construction by the company Sociedad Ibérica de Montajes. The parabolic cables, the deck, the suspension system, the cart, the gondola and the anchoring block on the Getxo side were all replaced. The only two significant modifications from its original design related to the beam and the suspension system.

The mixed suspension by suspension cables and shrouds characterised the empirist period of the first generation of suspension bridges, in which the function of the shrouds was analogical to that of the braces of the beam bridges. But the coexistence between both elements created uncertainty which made it impossible to make the calculation and adjustment between both suspension systems. The frequent breakages and the difficulties in the maintenance led to their almost generalised replacement, and occurred in the construction of the Brooklyn Bridge in 1935, or in the construction of the Rouen shuttle bridge.

However the elimination of the shrouds in the Vizcaya Bridge reduced its rigidity and therefore forced an increase in the beam’s inertia, which went from having an edge of two metres in the original project to three metres in the reconstruction. The primitive Saint Andrew crosses method was also changed for a Warren bean which had the advantage of being more reduced secondary efforts.

The new beam, the cart and the gondola were made by the company Compañía Anónima Basconia, the cables by the company Sociedad Franco Española de Cables, the suspension cables and the reconstruction of the top of the towers on the Getxo side were done by the company Sociedad Ibérica de Montajes and the new anchoring blocks in the Getxo side by Erdaide and Barrenechea.

The previous machine house was taken down and the new one, slightly smaller, was placed in a large hut higher up at the end of the deck at Getxo. The replacement of the electrical motor, which had been installed in 1901, was done by the company Eguren.

Initially the movement was controlled from a lookout point situated in the middle of the gondola.

1941 June 19. Inauguration of the restored Vizcaya Bridge.

1945 Elimination of the driving cabin in the gondola and the introduction of a cabin on the pillars on the Getxo side on the deck, attached to the machines hut next to Tower 2.

1964 April 14. Substitution of the gondola for a new unit built with aeronautical criteria and technique in Props and using materials resistant to marine corrosion.

1991 March15. Installation of a lighting system for night time performances with over 900 lighting points.

1995 December. Preparation by the future operating company of a General Report on the State of the Bridge’s Structures and Mechanisms.

1996 A non-postponable programme is prepared to remove auxiliary elements which are at risk of collapsing, making urgent reinforcements and repairs and to create auxiliary elements necessary to proceed to the following general repairs:

  • Removal of the old mobile scaffolding.
  • Repairs to the cart.
  • Balancing the tension of the gondola’s cables.
  • Replacement of the cast iron pulleys for polythene ones.
  • Trial with polythene wheels for the cart.
  • Repair of many track beams.
  • Construction of a motorised auxiliary cart (scaffolding).
  • Replacement of the stairs in the towers.
  • Restoration of the workshop, purchase of a winch and other machinery.
  • Repair of the primary and secondary structure at many points.
  • Studies in order to reduce the state of tension.
  • Restoration of the anchoring block in Portugalete.

1997 The following work was carried out:

  • Construction of a second moving scaffolding.
  • Construction of a climbing cart to repair cables.
  • Finite elements structural analysis contract.
  • Design and testing of a system to reinforce cables.
  • Design of a new type of sheet rail.
  • Reinforcement of 106 rail beams.
  • Installation of a welded continuous rail.
  • Removal of spotlights and 29,000 Kg of electrical cables and apparatus.
  • Full painting of the Bridge.
  • Reinforcement of cables at 29 points.
  • Changing the screws.

1998-1999 The following work was carried out:

  • Departments on the ground floor.
  • Ticket vending machines.
  • Construction of a scaffolding and auxiliary elements.
  • Rail.
  • New gondola.
  • Main cart
  • New boarding halls.
  • Automated system for services.
  • Pedestrian walkway.
  • Panoramic lifts.
  • Security installations.
  • Security system for the shops.
  • Lighting.
  • Vending and cancelling machines.
  • Substitution of the stairs in the tower.
  • Installation of the lifeline.

2000 The following work was carried out:

  • Repair of the top cables.
  • Partial repainting.
  • Small structural repairs.
  • Reinforcement of two cables.
  • Restoration of the deck’s lower structure.

2001 A new light lighting system is installed.

2002 Load resting criteria were corrected and trials were performed with anti-friction wheels.

2003 Some broken cords were repaired and the Creditrans application was introduced .