桥梁工程简介外文翻译.doc

兰州交通大学博文学院毕业设计（论文）外文翻译桥梁工程简介 桥梁是跨越如河流、山谷这样障碍的一种建筑，从而提供交通便利，到目前为止，大部分桥梁都是公路桥或铁路桥。大量的高架桥于19世纪在欧洲建成，目的是保持其运河中船舶的航行。最小的一座桥在纽约市的肯尼迪机场，它主要是把滑行飞机拖到跑道上服务的。 人类建成的第一座桥类似于原始人在孤立地带建成的。早期人类的工具和建筑技术如同原始人类一样都是最初级的，他们只要经过最少的加工和安装即可建成。 【关键字】 桥梁的发展 桥梁的种类1.桥梁的发展在森林里，随处可得结实的木材和圆木，那时侯的桥极可能是由一根或并排的几根圆木建成，可能在其上覆一些木枝或草垫以方便行走。 处于热带地区的印度、非洲、和南美洲纤维藤被用来建成悬索桥，这些藤被系在小河或山谷两边的树上或岩石上。一根或更多的藤被踩在上面行走，其它的则排列在膏腴几英尺的地方，用作手扶用。虽然藤索桥通常不稳定。但有很多用incas建成藤索桥有足够的坚固和稳定性，被用于西班牙士兵和它们马匹的通行。 在岩石地区，石头被用来建桥，横跨河流以很小的间距布置石碓作为桥墩，然后用平坦的石头横过相邻的桥墩就建成连接两岸的通道，大部分的石桥就是这种类型，叫做鼓掌桥。现在在Dartmoor、英格兰仍然可见，不过它们都建于中世纪甚至更晚。 原始桥梁的第一步变革被认为出现在中国古代，随后传入印度。河床一般比树要宽，中国人和印度人在河流的中央建成两个树桩。在这个结构的两端，用圆木的一端架在树桩上并微微向上倾斜，使其每一层都比它下面的高几英尺。为了增加稳定性，每个木桩在两岸都用一堆大而重的石头锚固；接近河中央，在河中间的两个木桩的两端则用简支梁连接。在这种结构中，天然支架桥在两个自由杆的中间加桩后可达到很宽的跨度。 早在公元前年的esopotamia和在公元千年的埃及，用石头或日光烤干的砖被用来安装重叠的横梁。这种结构看起来像的拱，下部更平稳，被叫做突拱。要使突拱变为更直的拱，它需要石头的内部构造适合光滑。这种直拱比突拱更坚固，且早在公元前年就被使用。 这种直石拱具有经济和经久耐用，它可以由许多静止在码头上的拱而跨过小的河流。并且，它一般会经常出现，而它的质量比先前的任何结构都要好。在中国和罗马的古代，这种整体石拱被广泛地用于桥梁结构。它一直被广泛地使用直到19世纪。 2.桥梁的种类这里有4类基本结构可以用作水面上的或障碍物上的桥：刚架桥、悬臂桥、拱桥、和悬索桥体系。 刚架桥最简单也可能是最早使用的-即刚架桥河流。这样它的两端固定在相对的河岸。这种刚架桥可以组成某种形状的木梁、钢筋混凝土梁或更复杂的约束。刚架桥这种类型的桥的跨度可以采用在中间建桥墩或在峡谷建搁栅撑，再用几根横梁连接起来而增加跨度。刚架桥的材料必须能够承担压力和拉力。尽管它的名字叫曲梁，但实际上这种具有双重要求的杆能用于刚架桥上。结果，梁弯曲较高的部分的压力比直的部分低一半以上，如果他的受压承载力太弱，它将会成扣环，如果受拉承载力太弱，他将会破坏。 悬臂桥在利用中间桥墩的长跨距桥中它通常是不可行的桥梁结构。举个例子，在深而流速急的河流或软泥中，可能很难建桥墩使它有足够深度达到基岩层。在这种情况下，刚架桥结构用两根横梁就可以延伸从每岸伸出一根梁，而在两根梁的端部基础进行锚固。这种简单的刚架桥结构更具有静定性，而每一根锚固的梁的这种基础结构就叫悬臂桥，或许这种最简单而熟悉的悬臂桥例子便是跳水板。在普通的悬臂式桥梁中，悬臂梁端部之间的间隙是闭合的，为道路提供了连续的桥面。但是假如把这种桥梁在其闭合点断开，那么每一根悬臂梁都不需要另外设置支撑而可保持稳定。通常悬臂梁中间间隙是闭合的既是刚架桥。如此却使悬臂粮延伸了跨度。 悬索桥在没有中间桥墩的情况下比悬臂桥跨越更大的距离。悬索桥的支撑体系是靠连续可弯曲的缆绳的两端的锚固，悬索桥最简单的例子是杂技场高空走钢丝杂技演员用的钢丝。原始的悬索桥常常是一把很小的几根这样的钢丝系在一起来提供扶手和立足点的。在水平公路上的现代悬索桥则是由缆绳悬吊在车行道两边的下面。 拱桥则是相反于悬索桥的作用，在那些悬索桥缆绳自由的提供支撑力的地方，拱桥却是从它的两端支柱固定的向上弯曲。由于在形状上的不同，悬索桥的缆绳的各点都趋向拉伸而拱桥的支柱的各处都趋于挤压。由于这些原因，悬索桥的缆绳必须尽可能的防止延伸，饿拱桥材料则尽可能地抵抗压缩。因为拱结构不一定要求材料具有抗拉强度，所以拱桥可以用砖或石头建造，砖或石头通过拱传递压力的特性结合在一起。这种材料在其它的基本桥梁结构中却毫无用处。 在拱桥中，荷载由公路上垂直传递下来，直到拱形遭到破坏。当拱遭到纯压而达到临界荷载时，便会改变力的传递路径。有压缩力的推力通过节点或墩传到地面。拱这种简单而优美的结构成为桥梁中的一种基本结构。introduction to bridge engineering Bridges that span rivers, valleys such a barrier construction, which provides convenient transportation, so far, most of the bridges are highway bridges or railway bridge. A large number of viaducts built in the 19th century in Europe, aims to maintain its navigation of the ship canal. The smallest bridge in New York Citys Kennedy Airport, it is primarily the aircraft taxiing onto the runway to the service.Humans is similar to the first bridge built in the primitive built in isolated areas. Early human tools and construction techniques as the original, like humans are the most junior. After they are at least as long as the processing and installation can be completed.【Key words】 development of bridge, the type of bridge1. The development of bridgeIn the forest, widely available solid wood and logs, then most likely Hou bridge or by a few logs built side by side, may, in its number of wooden sticks or straw mats on the cover for easy walking.In the tropical regions of India, Africa, and South America are used to build fiber rattan suspension bridge, the vines are tied to trees on both sides of the river or valley or rock. One or more above the walking cane to be stepped on, others are arranged in Gao Yu a few feet, for hand use. Although rattan rope bridge is usually unstable. But there are many rattan rope bridge with incas built strong and stable enough, to be used for the Spanish soldiers and their horses to pass.In rocky areas, the stone is used to bridge across the river to a small stone pestle as piers spaced, and then use a flat stone across the pier adjacent to the channel linking the two sides completed, most of the stone bridge is this types, called the clap bridge. Now in Dartmoor, England are still visible, but they are built in the Middle Ages or even later.The first step changes the original bridge was considered in ancient China, and then into India. Generally wider than the tree bed, Chinese and Indians in the center of the river into two stumps. In this structure, both ends of the frame with one end of logs on the stump, and tilted slightly upward so that each layer of high than a few feet below it. In order to increase stability, both sides each with a bunch of stakes in large and heavy stone anchor; close to the river, in the middle of the river at both ends of the two stakes are connected with beams. In this structure, the natural bridge support bar in the middle of two free pile after a wide span can be achieved.As early as 4000 BC in Mesopotamia, and thousands in the year 3000 in Egypt, with stone or sun dried bricks were used to install the overlapping beams. This structure looks like the arch, the lower more stable, is called sudden arch. To suddenly arch into a more straight arch, it needs to fit the internal structure of the stone smooth. The arch straight arch stronger than sudden, and as early as 500 BC to be used.The stone arch with direct economic and durable, it can rest on the dock by a number of the arch and across the small river. And, it generally will always appear, and its quality in any structure to be better than the previous. In ancient China and Rome, which is widely used in the overall stone arch bridge structure. It has been widely used until the 19th century.2. The type of bridgeThere are four categories of basic structure can be used as water or obstructions on the bridge: rigid frame bridge, cantilever bridge, arch, and suspension system.The simplest bridge may be just the first use - or just the river bridge. So that it is relatively fixed at both ends of the banks. This rigid frame bridge can form a shaped wooden beams, reinforced concrete beams or more complicated constraints. Just this type of bridge span of the bridge pier was built in the middle can be used or built in the valley support joists, beams connected by a few and then increase the span. Rigid Frame material must be able to bear the stress and tension. Despite its name beam, but in fact the requirements of this dual rod can be used to frame the bridge. Result, the higher part of the beam bending pressure lower than the straight part of the more than half, if hes bearing strength is too weak, it will be into the ring, if the tensile capacity is too weak, he will be destroyed.Cantilever bridge piers in the use of long-span bridges the middle it is usually not feasible in the bridge structure. For example, in the deep and rapid river flow, or ooze, it may make it difficult to build sufficient depth of bridge pier foundation rock. In this case, just on the bridge structure can be extended with two beams - out of a beam from each shore, and in the two ends of the beam anchorage basis. This simple structure is more rigid frame bridge with static characterization, and each root anchorage of the beam cantilever bridge called such an infrastructure, and perhaps this most simple and familiar example is the cantilever bridge diving board. Cantilever bridge in general, the gap between the cantilever tip is closed, the road to provide a continuous deck. But if the point of this bridge in its closed off, then do not need each other to set the root cantilever support which can maintain stability. Cantilever is usually only the middle of the gap is closed rigid frame bridge. So while filling grain extended cantilever span.Suspension bridge in the absence than in the case of the middle pier cantilever bridge across the greater distance. Suspension of the support system is a continuous flexible cables by the ends of the anchor, the suspension bridge is the simplest example of high-altitude high-wire acrobat with the circus wire. The original suspension bridge is often a very small few that is tied to steel rails and provide a foothold. At the level of the modern suspension bridge on the road is suspended by the cable on both sides of the roadway below.Arch is the opposite effect on the suspension bridge, suspension bridge cables in the freedom of those who provide support force where it is from the bridge pillars at both ends of its fixed upward. As different in shape, susp