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A rolled steel girder is a girder that has been fabricated by rolling a blank cylinder of steel through a series of dies to create the desired shape. These create standardized I-beam and wide flange beam [7] shapes up to 100 feet in length. A plate girder is a girder that has been fabricated by welding plates together to create the desired ...
Single box girder bridge , flyover above eastern approach of the San Francisco–Oakland Bay Bridge. A box girder bridge, or box section bridge, is a bridge in which the main beams comprise girders in the shape of a hollow box. The box girder normally comprises prestressed concrete, structural steel, or a composite of steel and reinforced concrete.
In practice, to overcome the decrease in workability of the concrete due to low E/C ratios, superplasticizers are used to deflocculate the fines (cement, mineral additions, ultra-fines). [9] [10] [11] The composition of the HPC80 concrete used for the Elorn Bridge was as follows: [12] Saint-Vigor CPA HP PM cement: 150 kg/m3; Saint-Renan 0/4 ...
A grid deck uses beams and diaphragms as the supporting structure. The supporting system of a grid deck is analyzed using a grillage analysis. A slab deck is one where the deck is analyzed as a plate. If the slab has a stiffness that is different in two directions (at right angles), then the deck is known and analyzed as an orthotropic deck.
The concrete elements may be reinforced or prestressed. Such modern bridges include girder , plate girder , and box girder bridges, all types of beam bridges. Types of construction could include having many beams side by side with a deck across the top of them, to a main beam either side supporting a deck between them.
In the deck-type bridge, a wood, steel or reinforced concrete bridge deck is supported on top of two or more plate girders, and may act compositely with them. In the case of railroad bridges, the railroad ties themselves may form the bridge deck, or the deck may support ballast on which the track is laid.
An extradosed bridge employs a structure that combines the main elements of both a prestressed box girder bridge and a cable-stayed bridge. [1] [2]: 85 [3] The name comes from the word extrados, the exterior or upper curve of an arch, and refers to how the "stay cables" on an extradosed bridge are not considered as such in the design, but are instead treated as external prestressing tendons ...
The illustrations are of modern pipe-column falsework, used to support the formwork for a post-tensioned reinforced concrete flyover connector for the eastern span replacement of the San Francisco-Oakland Bay Bridge. When the supports are complete, wood beams and plywood or reusable metal forms will be placed, reinforcing and tenon conduits ...