General Rafael Urdaneta Bridge
10.574306 - 71.592064Koordinaten: 10 ° 34 ' 27.5 "N, 71 ° 35' 31.4 " W
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The General Rafael Urdaneta Bridge ( locally simply puente sobre el Lago - bridge over the lake called ) is a 8678 meter long road bridge over Lake Maracaibo in Zulia state in Venezuela, the city of Maracaibo in a direct way with the other parts of the country of Venezuela joins, particularly on the National Road 3, with the capital Caracas. It is named after a native of Maracaibo major Colombian President Rafael Urdaneta and General.
She was at its completion, the longest cable-stayed bridge in the world and is considered the first cable-stayed concrete bridge.
Description
The bridge crosses the Straits Canal de San Carlos on a south of the center of Maracaibo located route, which is not the shortest route, but where space for the connections of the bridge on its secondary roads was sufficiently available. In addition, the soil conditions there were not quite as difficult as on the direct route.
From Maracaibo from a long ramp bridge rises to the cable-stayed bridge with six pylons and five openings with spans of 235 meters, all of which have a clear height of 45 m above the water level. On the other side of the descending portion of the ramp bridge a few meters turns into a long, flat stretch over the water and reached via a causeway the opposite shore.
The bridge has four lanes, which are separated in the middle by guard rails, but no hard shoulder and no walking or biking trails.
The six pylons can be illuminated in different colors at night.
History
Had the Venezuelan Ministry of Public Works ( Ministerio de Obras Públicas ) in 1957 in his bid for the planning and construction of a railway and road bridge over Lake Maracaibo a main opening with a span of 400 m, five more openings 150 m and a clear height of 45 m required, but everything else left to the bidders. The offers for various steel bridges were 284-760 million Bolivares (then U.S. $ 1 = 3.35 B ). Only the offer of Consorcio Puente Maracaibo company Precomprimido, Caracas and Julius Berger, Wiesbaden, Germany for 330 million Bs provided for a reinforced concrete structure as designed by Riccardo Morandi. It was intended to span the required large main opening with a cable-stayed bridge with two pylons, which would have been much larger than all previously known bridges of this type. This offer was successful, as was expected of a concrete structure lower maintenance costs, had to be less imported and a large number of local engineers to gain experience in prestressed concrete.
On August 15, 1957, the contract between the Ministry of Construction and the Consorcio Puente Maracaibo was signed, which was extended by the company Grün & Bilfinger, Philipp Holzmann and Wayss & Freytag. For the difficult soil mechanical issues Jean Kerisel from Paris was consulted. The Laboratório Nacional de Engenharia Civil, Lisbon was commissioned to model experiments by the client. As test engineers Pierre Lardy, Gerold reapers and Fritz Stiissi from ETH Zurich have been active.
1958 investigated the new Venezuelan government for ways of reducing costs. It thus waived the function of the railway bridge and changed the large main opening into five smaller openings.
The actual construction began in April 1959 and were carried out during the period contracted. On August 24, 1962, the bridge by Rómulo Betancourt, the former president of Venezuela, officially opened.
Technical details
The 8678.60 m long bridge structure consists of a total (starting on the shore of Maracaibo ) from 135 frames and a dam, which are given below with the respective spans in meters: 22.6 / 2 x 46.6 / 65.8 / 15 x 85/160 / 5 × 235/160 / 11 x 85 / 65.8 / 77 x 46.6 / 20 x 36.6 / 35.8 / 406 ( dam ).
The Lake Maracaibo is on the route up to 18 m deep, among which are layers of silt and other, less sustainable soil layers. All the pillars had therefore to a depth of 56 m reaching piling and bored piles are founded, were concreted to the projecting out of the water pile caps.
The long bridge could in the short time and are built cheaply with as many equal parts. Relatively simple construction is the about 4.3 km long, flat eastern part with a span of 36.6 m and 46.6 m. As with a Trestle the roadway is supported by a respective concrete frame with four vertical supports. Between these concrete frames were suspended four prefabricated prestressed concrete beam on land next to each other, which were up to a height of ten meters floated directly from two barges. With the rising up to 24 m height, a floating crane was required. After closing the gaps between the beams and the cross bracing so that the plate was made for the road.
The pillars of the stronger rising Fields with spans of 85 m consist of V-shaped structures made of 2 x 4 reinforced concrete struts wear a concrete pillar on site table of prestressed concrete. The slow rise of the ramp is achieved by the base of the same V- structures are always set to increasingly higher struts to an X-shaped structure. Between the pillars tables turn four prefabricated beams were hooked.
The pylons of the cable-stayed bridge consists of two side of the road carrier arranged A-shaped frames that are 92.5 meters high and slightly tilted inward. Their stems have a square cross-section which tapers upwards. These frames are up and connected by cross bars to each other under the deck.
Within the frame in turn a large V-shaped structure made of 2 x 2 wide concrete strut is arranged, which is overlaid by a substantially concealed by the pylon frame A structure. It is therefore also known as XX- pillar. This XX- pillar carries a 44.39 m long pier table, which consists of a closed, three-cell prestressed concrete box with a 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, which were lifted by a floating crane and supported at its outer end by auxiliary pier. At their outer ends of one side over the edge protruding beyond rope cross member is fitted in each case. This created a road carrier of 189.05 m length. Subsequently, each with 16 fully closed, 7.4 cm thick stay cables were pulled over the cable saddle bearing on the pylon tips and anchored in the cable cross members.
Between supported by the XX- pillar and the stay cables attached 189,05 m long road carriers in turn four prefabricated 46 m long prestressed concrete beams were hung with which the gap was closed. The span between the pylon -axis thus is 235.05 m.
The track support is total, but without the side mounted rope anchors, 17,40 m wide. On it two paved carriageway with 7.20 m width are arranged, which are separated by a 1.20 m wide median strip with guardrails.
Shipwreck
On April 6, 1964, the 67 -meter-long tanker Esso Maracaibo collided after the failure of its electrical systems with the bridge, which the pillars 31 and 32 collapsed. In this case, seven people were killed, who drove over the bridge. The bridge was restored by Precomprimido.