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The old Britannia Bridge with train track inside the box-girder tunnel Section of the original tubular Britannia Bridge The patent curved and tapered box girder jib of a Fairbairn steam crane. A box girder or tubular girder (or box beam) is a girder that forms an enclosed tube with multiple walls, as opposed to an Ɪ-or H-beam.
Anchor channels, invented by Anders Jordahl in 1913, are steel channels cast flush in reinforced concrete elements to allow the installation of channel bolts for the fastening of components. Anchor channels consist of steel C-shaped channels and anchors (mostly headed studs ) which are connected to the channel by welding or riveting/forging.
During the manufacturing process the mother tube goes through a series of shaping stands which form the round HSS (mother tube) into the final square or rectangular shape. Most American manufacturers adhere to the ASTM A500 or newly adopted ASTM A1085 standards, while Canadian manufacturers follow both ASTM A500 and CSA G40.21.
For removable forms, once the concrete has been poured into formwork and has set (or cured), the formwork is struck or stripped to expose the finished concrete. The time between pouring and stripping depends on the job specifications, which include the cure required, and whether the form is supporting any weight; it is usually at least 24 hours ...
The first expanded polystyrene ICF Wall forms were developed in the late 1960s with the expiration of the original patent and the advent of modern foam plastics by BASF. [citation needed] Canadian contractor Werner Gregori filed the first patent for a foam concrete form in 1966 with a block "measuring 16 inches high by 48 inches long with a tongue-and-groove interlock, metal ties, and a waffle ...
A precast concrete walled house under construction An example of low-quality precast concrete with exposed dowels, connectors, indications of cracks, and malformations, even during its installation, Barangay Lantic, Carmona, Cavite, Philippines Interior view of the walls, supports, and roof of a precast commercial shop in Williston, North Dakota, US.
Straight, clear, smooth concrete-walled channels speed up flow, and are therefore likely to make flooding downstream worse. Modern flood control seeks to "slow the flow", and deliberately flood some low-lying areas, ideally vegetated, to act as sponges, letting them drain again as the floodwaters go down.
The inception of form liners began with fairly simple images for concrete, including cut-out shapes and silhouettes resting on a background texture. As time passed, these designs grew in complexity, and creative artists and sculptors began to work with form liner manufactures to produce and design anything imaginable in concrete walls, and on a ...