Low Tensile Strength    As stated（叙述）earlier, the tensile strength of concrete is much lower than its compressive strength (about 1/10), and hence concrete is subject to（易遭受）cracking. In structural uses this is overcome by using reinforcement to carry tensile forces and limit crack widths（宽度）to within acceptable values. Unless care is taken in design and construction, however, these cracks may be unsightly（难看）or may allow（使..能）penetration（渗透）of water.

    低的抗拉强度   正如前面所述的，混凝土的抗拉强度比它的抗压强度要低得多（约1/10），因而混凝土易遭受开裂。在结构使用中，通过采用钢筋承受拉力，并限制裂缝宽度在可接受的数值内来克服这一点。但是，除非在设计与施工中小心谨慎，否则这些裂缝可能会难看或使水渗透。
    Forms and Shoring                The construction of a cast-in-place structure（现浇结构）involves（涉及）three steps（步骤）not encountered in the construction of steel or timber structures. These are (a) the construction of the forms, (b) the removal（拆除）of these forms, and (c) propping or shoring（支撑）the new concrete to support its weight until its strength is adequate. Each of these steps involves（包含）labor（人工）and/or materials which are not necessary with other forms of construction（建筑形式）.

    模板和支撑    现浇结构的施工涉及到三个步骤在钢结构或木结构的施工中不会遇到。它们是(a)模板的施工；(b)模板的拆除；(c)支撑新浇混凝土，支撑其重量直至混凝土达到足够的强度。每一步都包括其他建筑形式中不必要的人工和/或材料。
    Relatively Low Strength Per Unit of Weight or Volume         The compressive strength of concrete is roughly 5% to 10% that of steel, while its unit density is roughly 30% that of steel. As a result, a concrete structure requires a larger volume and a greater weight of material than does a comparable（类似的） steel structure. As a result, long-span structures（大跨结构）are often built from steel.

    相对低的单位重量或单位体积的强度     混凝土的抗压强度大约是钢材的5%-10%，而它的单位密度约是钢材的30%。因此，混凝土结构与类似的钢结构相比需要较大的材料体积和较重的材料重量。因此，大跨结构常常由钢材制造。
    Time-dependent volume changes         Both concrete and steel undergo approximately the same amount of thermal expansion and contraction. Because there is less mass of steel to be heated or cooled（变热或变冷）, and because steel is a better conductor（导体）than concrete, a steel structure is generally affected by temperature changes to a greater extent （程度）than is a concrete structure. On the other hand, concrete undergoes drying shrinkage（干缩）, which, if restrained, may cause deflections or cracking. Furthermore, deflections will tend to increase with time（随时间）, possibly doubling（双倍）, due to creep（徐变）of the concrete under sustained loads（持续荷载）.
    体积随时间变化    混凝土与钢筋都经过了大约相同量的热膨胀和收缩。因为变热或变冷的钢材质量较少，且钢材与混凝土相比是一种较好的导体，因此，钢结构通常受温度变化的影响程度比混凝土结构要大。另一方面，混凝土经历了干缩，如果受到约束，干缩可能会引起挠度或开裂。而且，挠度往往会随着时间增加，其值由于混凝土在持续荷载作用下的徐变而可能会是两倍。
            The first set of building regulations（建筑规范）for reinforced concrete were drafted（起草）under the leadership of（在..的领导下） Professor Morsch of the University of Stuttgart and were issued（发布）in Prussia in 1904. Design regulations were issued in Britain, France, Austria, and Switzerland between 1907and 1909.

            在Stuttgart（斯图加特）大学Morsch教授的领导下起草了第一套钢筋混凝土的建筑规范，并于1904年在Prussia（普鲁士）发布。1907-1909年在英国、法国、奥地利和瑞士发布了设计规范。
             The American Railway Engineering Association（协会） appointed（任命）a Committee on Masonry（砌体委员会）in 1890. In 1903 this committee presented（提出）specifications for Portland cement concrete. Between 1908 and 1910 a series of committee reports led to the Standard Building Regulations for the Use of Reinforced Concrete published（发表）in 1910 by the National（国家的）Association of Cement Users（用户）which subsequently（随后）became the American Concrete Institute（协会）.

            美国的铁路工程协会在1890年任命了一个砌体委员会。该委员会在1903年提出了波特兰水泥混凝土的规范。1908-1910间，一些列的委员会报告使国家水泥用户协会在1910年发表了钢筋混凝土使用的标准建筑规范，其随后成为美国混凝土协会。