156 X2 Category 2: Civil Structures The bridge over the Danube-Black Sea Channel from Agigea - km 0 + 540 - is located at the confluence of the Black Sea and the Channel, near Constanta seaport. The bridge ensures the connection between the Northern and Southern zones of the harbour, now separated by the Danube-Black Sea navigable canal. The structural engineers from Search Corporation SRL are using Allplan Engineering to carry out this special project. The bridge and access viaducts have a total length of 906.82 m, with 362.00 m for the bridge and 544.82 m for the viaducts. The overpass of the Danube-Black Channel is carried out with a cable-stayed bridge which has three spans of 81.40 m and 200.00 m + 81.40 m; the superstructure has a total length of 362.80 m. The deck of the cable-stayed bridge is made from a composite structure (steel + concrete), partly made of prestressed concrete on the lateral spans, and metal, partly in collaboration with the flooring from the reinforced concrete of the bridge superstructure. The access viaduct decks are made from prestressed, precast, reinforced concrete beams, which works through a monolithic plate and prestressed concrete cross pieces. Above the anchorage area, the pillars are made from composite sections: steel box (where the anchorages of the cables are positioned) embedded in concrete. The cooperation is achieved with flexible connectors welded to the steel box of the anchorages. The total height of these pillars is 62.00 m. The design elements for the bridge over the canal and viaducts, as required by the specifications and project are: • The clear height under the bridge should be equal to the railway bridge from the lock, which is 17.70 m and provides the navigation gauge required for the DanubeBlack Sea Channel which has a height of 17.50 m, a width of 35.00 m in the middle of the waterway and 10.00 m on the remaining width. This is required by both technical and economic conditions and also for ensuring the safety zones, protection and stability of the channel section; • The bridge is equipped with a roadway width of 14.80 m, which provides four lanes: two lanes for traffic and two lateral pedestrian sidewalks with a minimum width of 75 cm; • A life-time of at least 50 years, designed according to norm AND 554-2002; • The structural strength of the bridge over the canal and the access viaducts is designed for live loads according to STAS 3221-86 “Bridges Road. Convoy type and class loading”; • In terms of the seismic design, the work is placed according to norm SR-EN 1998-2:2006 and National Annex SR-EN 1998-2: 2006/NA: 2010. In the cross-section, the bridge superstructure is made from two steel box coffered girders in collaboration with reinforced concrete flooring, respectively from two prestressed concrete coffered beams. The solution adopted for the execution of the bridge is characterised by the modern design structure, which presents a number of technical and economic advantages such as: • Combination of relatively simple structural components with known technologies in a unitary complex structure; • Reducing the duration of construction, with all the benefits arising from achieving this goal; • Achieving a work with a particular architectural aspect; • Achieving a work with a height of reduced construction, of only 3.05 m, representing approximately L / 70 of the central span of the bridge, L = 200 m. Workflow with Allplan Engineer The design started with the generation of the digital model of the terrain using the specific functions from Allplan (Digital Terrain model). The road and the deck elements were created using the Bridge/Civil Engineering module. The general arrangement drawing files were realised directly from 3D using the Associative Views module. Because of the reinforcement complexity, the reinforcement model had to be checked for every inserted placement of bars. Using the function Collision check and displaying bars with different surface colours, the structural engineers did this more efficiently. Special 3D objects and textures were used for obtaining a realistic presentation. Bridge over the Danube - Agigea Constanta, Romania Software: Allplan Engineering
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