General Rafael Urdaneta Bridge

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Coordinates: 10 ° 34 ′ 28 "  N , 71 ° 35 ′ 31"  W.

General Rafael Urdaneta Bridge
General Rafael Urdaneta Bridge
use Road bridge
place Maracaibo
construction Cable-stayed bridge , prestressed concrete bridge
overall length 8678 m
width 17.40 m
Longest span 5 × 235 m
Clear height 45 m
start of building 1959
completion 1962
planner Riccardo Morandi
location
General Rafael Urdaneta Bridge (Zulia)
General Rafael Urdaneta Bridge
Puente Sobre el Lago de Maracaibo visto desde visita tu puente 07.jpg
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The General Rafael Urdaneta Bridge (locally also simply called puente sobre el Lago - bridge over the lake ) is a 8,678 meter long road bridge over Lake Maracaibo in the state of Zulia in Venezuela , which connects the city of Maracaibo directly with the rest Connects parts of Venezuela, in particular via the national road 3 with the capital Caracas . It is named after the Great Colombian General and President Rafael Urdaneta from Maracaibo .

When it was completed, it was the longest cable-stayed bridge in the world and is considered the first concrete cable-stayed bridge.

description

The bridge crosses the Strait Canal de San Carlos on a south of the center of Maracaibo situated route, which is not the shortest route, but where space for the connections of the bridge was enough available to their secondary roads. In addition, the ground conditions there were not quite as difficult as on the direct route.

A long ramp bridge rises from Maracaibo to the cable-stayed bridge with six pylons and five openings with spans of 235 m each, all of which have a clear height of 45 m above the water level. On the other side, the descending part of the ramp bridge turns into a long, flat stretch just a few meters above the water and reaches the opposite bank via a dam.

The bridge has four lanes , which are separated in the middle by guard rails , but no hard shoulders and no sidewalks or bike paths.

The six pylons can be illuminated in different colors at night.

Planning and construction history

The Venezuelan Ministry of Construction ( Ministerio de Obras Públicas ) had a main opening with a span of 400 m, five further openings with 150 m and a clearance height of in its 1957 tender for the planning and construction of a railway and road bridge over Lake Maracaibo 45 m required, but everything else is left to the bidders. The offers for various steel bridges were between 284 and 760 million bolivares (at the time US $ 1 = 3.35 Bs). Only the offer of the Consorcio Puente Maracaibo of the companies Precomprimido , Caracas and Julius Berger , Wiesbaden, for 330 million Bs provided for a reinforced concrete structure according to the design by Riccardo Morandi . It was planned to span the required large main opening with a cable-stayed bridge with two pylons, which would have been considerably larger than all bridges of this type known up to that point. This offer was successful because lower maintenance costs were expected from a concrete structure, fewer had to be imported and a large number of local engineers were able to gain experience in prestressed concrete construction.

On August 15, 1957, the contract between the Ministry of Construction and the Consorcio Puente Maracaibo was signed, which was expanded to include the companies Grün & Bilfinger , Philipp Holzmann and Wayss & Freytag . Jean Kerisel from Paris was brought in to answer the difficult soil mechanical issues . The Laboratório Nacional de Engenharia Civil in Lisbon was commissioned by the client to carry out model tests. As test engineers were Pierre Lardy , Gerold reaper and Fritz Stüssi from the ETH Zurich operates.

In 1958 the new Venezuelan government looked for ways to reduce costs. The function of the railway bridge was therefore abandoned and the large main opening was changed into five smaller openings.

The actual construction work began in April 1959 and was carried out in the contractually agreed time. The surveying work was headed by Heinz Günther Henneberg , who made this the subject of his doctoral thesis submitted in 1962 . On August 24, 1962, the bridge was inaugurated by Rómulo Betancourt , then President of Venezuela.

Technical details

The 8,678.60 m long bridge structure consists of a total of 135 fields and a dam, which are specified below with the respective spans in meters (starting on the banks of Maracaibo):
22.6 / 2 × 46.6 / 65.8 / 15 × 85/160/5 × 235/160/11 × 85 / 65.8 / 77 × 46.6 / 20 × 36.6 / 35.8 / 406 (dam).

The Maracaibo Lake is up to 18 m deep on the route, underneath there are layers of silt (2 to 28 m) and older layers which, according to the standard penetration test, achieved impact numbers of over 20 per 30 cm and are therefore considered “solid ground “ ( Terreno firme ). It consists mainly of sand with lenses of silt and clay (up to 10 m thick) and strips of sandstones and conglomerates. At a depth of around 90 m (measured from the water level) there was a layer of hard clay that rose to the west. All pillars therefore had to be built in the “solid ground” to a depth of 56 m, driven and bored piles onto which the pile head slabs protruding from the water were concreted. Driving and bored piles were prefabricated from concrete. In some places the soil was so bad that large bored piles 135 cm in diameter made of prestressed concrete were used (712 in total). They were up to 57 m long and 110 tons in weight and could carry up to 2000 tons, were placed in the boreholes with a crane and grouted with cement.

The long bridge could only be built in the short time and cost-effectively with as many identical parts as possible. The roughly 4.3 km long, flat eastern part is comparatively simply constructed with spans of 36.6 m and 46.6 m respectively. As with a yoke bridge, the roadway is supported by a concrete frame with four vertical supports. Between these concrete frames, four pre-fabricated pre-stressed concrete girders were hung next to each other, which were floated in by two barges up to a height of ten meters. A floating crane was required for the heights rising up to 24 m . After the joints between the girders and the transverse bracing had been closed, the slab for the roadway was made.

The pillars of the more steeply rising fields with spans of 85 m consist of V-shaped structures made of 2 × 4 reinforced concrete struts that support a pillar table made of prestressed concrete, which was concreted on site. The slow rise of the ramps is achieved by placing the bases of the same V-structures on ever higher struts until an X-shaped structure is created. Four prefabricated girders were hung between the pillar tables.

Top of one of the pylons

The pylons of the cable-stayed bridge consist of two A-shaped frames arranged on the side of the girder, which are 92.5 m high and slightly inclined inwards. Their stems have a square cross section that tapers towards the top. These frames are connected to one another by crossbars above and below the deck.

Inside the frame is a large V-shaped structure made of 2 × 2 wide reinforced concrete struts, which is overlaid by an A-structure that is largely hidden by the pylon frame. It is therefore also known as the XX pillar. This XX pillar carries a 44.39 m long pillar table, which consists of a closed, three-cell prestressed concrete hollow box with a construction height of 5 m. The pier tables were extended in both directions by 72.33 m long prestressed concrete cantilevers that were built on falsework that were lifted by a floating crane and supported at their outer end by auxiliary piers. At each of its outer ends, a cable cross member protruding laterally over the edge is installed. This created a roadway girder 189.05 m in length. Then 16 fully locked, 7.4 cm thick stay cables were pulled over the cable saddle bearings at the pylon tips and anchored in the cable cross members.

Between the 189.05 m long carriageway girders supported by the XX pillars and attached to the stay cables, four prefabricated 46 m long prestressed concrete girders were hung, with which the gap was closed. The span between the pylon axes is 235.05 m.

Overall, without the rope anchors attached to the side, the deck girder is 17.40 m wide. Two asphalt lanes 7.20 m wide are arranged on it, which are separated by a 1.20 m wide median strip with guard rails.

Ship accident and repair work

On April 6, 1964, the 198 m long tanker Esso Maracaibo (36,000 tons dwt , water displacement around 47,000 tons, loaded with 250,000 barrels of crude oil), loaded with oil, collided with the bridge after the failure of its electrical systems, causing piers 31 and 32 to collapse. Seven people were killed who drove over the bridge. The tanker came from the direction of Lake Maracaibo, where there are large oil deposits, especially in the eastern part. The tanker did not sink and was later used again, but oil spilled. It belonged to the then leading oil producer in Venezuela, the Creole Petroleum Corporation (controlled by Standard Oil of New Jersey). The tanker crew noticed the failure 2 km from the bridge and tried to brake with an anchor, which came too late. The ship's broadside hit the bridge away from the shipping route. The bridge was restored by Precomprimido.

Because of the high level of corrosion caused by the proximity of the sea and errors in maintenance, all suspension ropes had to be replaced in 1980. At the end of the 1990s, there was again a great need for renovation (corrosion on various reinforced concrete parts). The FLSTP (Fundación Laboratorio de Servicios Técnicos Petroleros) of the Universidad del Zulia has been responsible for checking the bridge since 1996 , and the Venezuelan construction company Precomprimido, which was also significantly involved in the construction of the bridge, for the maintenance work. Due to the dredging of Lake Maracaibo to deepen the shipping lines, there was an influx of salt water, which increased corrosion (the salt penetrates the concrete, also carried by the impact of the waves, and attacks the steel in the reinforced concrete). According to the FLSTP engineer (and retired professor) Alfredo Navarro (2018), the pillars near the town of Maracaibo, where the shipping line runs, are the most affected (pillars 13 to 15 and 17 to 39 of a total of 134 pillars, the hardest near the shipping line between nos. 22 and 23). In 1996 and 2004 the pylons were painted with waterproof paint, the paint is renewed every 5 years. One problem is the roller bearings on which the suspension supports of the track are movably supported. In 2008 the track broke due to the damage to the roller bearings. In 2012, temporary supports were installed next to the roller bearings between pillars no. 20 to 25 in order to protect the girders resting on these in the event of failure. All roller bearings between No. 20 and No. 38 urgently need to be replaced (2018). The official bodies are generally reluctant to provide information about the condition of the bridge, but the engineer Alfredo Navarro assured in 2018 that there are no alarming risks, especially since the traffic load would be reduced (the pylons can carry 11,000 tons, but the load is currently at 2500 Tons). In August 2018, the bridge was closed for several days because a power line in the asphalt caught fire. Maintenance has been neglected for decades, according to a 2018 newspaper report by The Times . The control of the traffic to avoid overloading the bridge was also handled laxly (one of the weighing devices for trucks is defective).

The condition of the bridge aroused interest in 2018 because the Polcevera Viaduct in Genoa, a bridge similar to Morandi in many ways, collapsed. In contrast to the next two large cable-stayed bridges built by Morandi, the Maracaibo Bridge has no concrete sheathing for the steel cables.

Panorama of the bridge

literature

See also

Web links

Commons : General Rafael Urdaneta Bridge  - Album with pictures, videos and audio files

Individual evidence

  1. ↑ Hermann Drewes: Obituary - Heinz Günther Henneberg (1926–2016) , IAG newsletter, December 2016, pp. 7-8.
  2. ↑ The collison between "Esso Maracaibo" & the Bridge. Retrieved August 16, 2018 .
  3. ^ Tanker Tears Big Gap in Venezuelan Bridge; 5 Drown as Vehicles Plunge Into Water Oil Coats Lake , The New York Times, April 8, 1964. Five people died afterwards.
  4. ^ C. Ostenfeld, Ship collisions against bridge piers, IABSE Publications, Volume 25, 1965, p. 233
  5. ↑ Habib Tabatabai: Inspection and Maintenance of Bridge Stay Cable Systems, NCHRP Synthesis 353, Transportation Research Board, Washington DC 2005, p. 24, google books
  6. ↑ Walter F. Silva-Araya, Oladis T. de Rinc ¢ n, Luis Pumarada-O'Neill (Ed.), Repair and rehabilitation of reinforced concrete structures: the state of the art: proceedings of the international seminar, workshop and exhibition , Maracaibo, Venezuela, April 28-May 1, 1997, ASCE 1998
  7. ↑ Rosa Munoz Lima, A Morandi Bridge is also fighting for its stability in Venezuela , msn Nachrichten, August 18, 2018
  8. ↑ Victoria Rodriguez, Corrosión en 26 pilas puede colapsar al “Coloso” , Versión Final, August 22, 2018
  9. ↑ Stephen Gibbs: Venezuela's Morandi highway hasn't been inspected in decades , The Times, August 17, 2018
  10. ↑ Hanns Simons, Heinz Wind, W. Hans Moser: The bridge over the Maracaibo Lake in Venezuela, Bauverlag Wiesbaden-Berlin, 1963