1、Suspension Bridges 悬索桥1.Suspension bridges are frequently constructed in preference to other types of bridges, 悬架桥经常优先于其他类型的桥梁构造，especially where relatively light traffic has to be carried over long spans since they are more economical in material and are extremely strong. 尤其适用于跨度相对长的交通，因为它们具有更经济、更牢
2、固的材料。There are in existence suspension bridges with main spans of more than 3,000 feet, 有些悬索桥，主跨超过 3000 英尺，the entire weight of the deck being supported from above by cables (usually only two or four in number) suspended between two towers at either side of the river. 悬浮在分布于河流两侧的两塔之间的甲板上的全部重量的支持来自上述
3、的电缆（通常只有两个或四个号码）。2. The cables are composed of thousands of wires, made of high-tensile steel, which are galvanized to resist corrosion. 该电缆包含着数以千计的电线，这些电线由高强度钢制成，这种镀锌的钢抗腐蚀。Two or three hundred of these wires, each of about 0.19 inches in diameter, are clamped together to form a single strand,这些线，每个
4、直径约 0.19 英寸，通常两三百根线被夹紧在一起，以形成单链，and the whole cable may consist of a considerable number of such strands compacted and bound together with wire. 整条电缆可能包括了相当数量的被捆绑在一起、压紧了的此类单链。In constructing the cable, two distinct methods may be adopted. 在建设电缆时， 可以采用两种不同的方法。This latter method obviously involves a m
5、uch longer spinning operation。后一种方法显然涉及到一个更长的纺丝操作。since each wire or small group of wires must be spun and adjusted to the correct sag individually, 因为每条线或每小组的电线必须个别调整，以调整个别下垂，whereas the strands of twisted wire can be erected as units, provided that they are not so heavy as to be unmanageable. 而股绞线
6、可以设置为单位，只要他们不是很沉重以至于无法管理。However, on bridges with very long spans, there are certain advantages in the parallel wire method of spinning the cable. 然而，在很长跨度的桥梁上，平行纺线法也有一定的优势。3.The cables are normally made continuous through the tops of the towers, down through side towers, there these exist, and then
7、 into the anchorage. 电缆通常连续通过塔的顶部，下通过侧塔，有这些存在，然后进入锚地。They bear on specially constructed saddles on the towers, which are shaped to accommodate them, the saddles being either fixed so that the cables may slide over them, or mounted on rollers so that they may move with any movement of the cables.它们承担
8、着特殊构造的塔，这些形状，用以固定它们的连线，或安装在滚轴上，使他们可以与任一电缆间移动。In view of the enormous pull exerted by the heavy cables, their ends must be secured in firm anchorage, and unless they can be embedded in sound natural rock, constructions of masonry or concrete must be provided strong enough to withstand the Seya pressu
9、res put upon them. 鉴于沉重的电缆产生的巨大拉动作用，其两端必须固定在坚定的锚地，除非它们可以彻底地嵌入到天然岩石上，必须提供强大的砖石或混凝土结构使之足以承受加在它们之上的 Seya 压力。 The cable strands are normally looped round strand-shoes, which are in turn connected by chains to an anchor-plate embedded in the base of the anchorage. 电缆链通常被圈在鞋状线环里，依次连接作为嵌入锚地的基础的电缆链。4At inte
10、rvals along the main span, cast-steel cable-brands are attached to the cables, gripping them firmly and excluding moistures from them, and from these bands suspenders of wire-rope or chains hang down. 在区间上沿主跨，铸钢的钢丝绳，牢牢攥紧排除水分，由此这些钢丝绳呈索线吊带状或下垂链状。Since these suspenders gave to take the weight of the de
11、ck to which they are attached, they must have a high tensile strength. 由于这些吊带状可以承受与它们连接到的甲板重量，它们必须有高的抗拉强度。One advantage of using the braced-chain suspenders is that they largely dispense with the need for a system of stiffening, being themselves rigid.使用吊带状支撑链的一个优点是，它们在很大程度上免除需要一个固化系统，因为它们是刚性的。This
12、stiffening is necessary to resist deformations of the deck of the bridge due to moving traffic loads and also to resist lateral pressures from wind.这种刚性是必要的，用以抵抗变形的甲板上的移动流量负载，也抵抗侧向风对桥的压力。In the case of wire-rope suspenders, the stiffening must be provided by trusses constructed at the level of the deck, 钢丝绳呈吊带状的情况下，要使刚性加强，必须提供由上面的地板水平构成的桁架，the depth of the truss varying with the length of the span. 埋于深处的桁架跨度随着长度的变化而变化。
