2024年4月28日发(作者：)

中英文对照外文翻译

(文档含英文原文和中文翻译)

Reinforced Concrete

Concrete and reinforced concrete are used as building materials in

every country. In many, including the United States and Canada, reinforced

concrete is a dominant structural material in engineered construction.

The universal nature of reinforced concrete construction stems from the

wide availability of reinforcing bars and the constituents of concrete,

gravel, sand, and cement, the relatively simple skills required in

concrete construction, and the economy of reinforced concrete compared

to other forms of construction. Concrete and reinforced concrete are used

in bridges, buildings of all sorts underground structures, water tanks,

television towers, offshore oil exploration and production structures,

dams, and even in ships.

Reinforced concrete structures may be cast-in-place concrete,

constructed in their final location, or they may be precast concrete

produced in a factory and erected at the construction site. Concrete

structures may be severe and functional in design, or the shape and layout

and be whimsical and artistic. Few other building materials off the

architect and engineer such versatility and scope.

Concrete is strong in compression but weak in tension. As a result,

cracks develop whenever loads, or restrained shrinkage of temperature

changes, give rise to tensile stresses in excess of the tensile strength

of the concrete. In a plain concrete beam, the moments about the neutral

axis due to applied loads are resisted by an internal tension-compression

couple involving tension in the concrete. Such a beam fails very suddenly

and completely when the first crack forms. In a reinforced concrete beam,

steel bars are embedded in the concrete in such a way that the tension

forces needed for moment equilibrium after the concrete cracks can be

developed in the bars.

The construction of a reinforced concrete member involves building

a from of mold in the shape of the member being built. The form must be

strong enough to support both the weight and hydrostatic pressure of the

wet concrete, and any forces applied to it by workers, concrete buggies,

wind, and so on. The reinforcement is placed in this form and held in place

during the concreting operation. After the concrete has hardened, the

forms are removed. As the forms are removed, props of shores are installed

to support the weight of the concrete until it has reached sufficient

strength to support the loads by itself.

The designer must proportion a concrete member for adequate strength

to resist the loads and adequate stiffness to prevent excessive

deflections. In beam must be proportioned so that it can be constructed.

For example, the reinforcement must be detailed so that it can be assembled

in the field, and since the concrete is placed in the form after the

reinforcement is in place, the concrete must be able to flow around,

between, and past the reinforcement to fill all parts of the form

completely.

The choice of whether a structure should be built of concrete, steel,

masonry, or timber depends on the availability of materials and on a number

of value decisions. The choice of structural system is made by the

architect of engineer early in the design, based on the following

considerations: