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专业：土木工程（桥梁方向）
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2010 年 3 月
What is traffic engineering
Traffic engineering is still a relatively new discipline within the overall bounds of civil engineering. it has nevertheless already been partially planning. the disciplines are not synonymous though. transportation planning is concerned with the planning, functional design, operation and management of facilities for any mode of transportation in order to provide for the safe, rapid, comfortable, convenient, economical and enviromenally-comparible movement of people and goods. within that broad scope, traffic engineering deals with those functions in respect of roads, road networks, terminal points , about lands and their relationships with other modes of transportation.
Those definitions, based on the 1976 ones of the U.S.institute of transportation engineers are complete than, the British instituting of civil engineering which deals with traffic planning and design of roads, of frontage development and of parking facilities and with the control of traffic to provide safe, convenient and economical movement of vehicles and pedestrians.
The definitions of the disicipline are becoming clearer: the methodology is developing continuously and becoming increasingly scientific. the early rule-of-thumb techniques are disappearing.
Traffic problem
The discipline is young: the problem is large and still growing. in 1920 the total number of motor vehicles, licensed in great Britain was,650,000.fifty year later the comparable figure was 14,950,000-a growth factor of 23 times. in recent years the rate of growth has slackened somewhat, but it is still considerable: 1955 6,466,000
1960 9,439,000
1965 12,938,000
1970 14,950,000
1974 17,247,000
In order to see the problem in every day terms ,consider high street. anywhere. assuming that present trends continue, it is expected that within the next fifteen years of so the traffic on this road will increase by around forty to fifty persent. if this increased volume of traffic were to be accommodated at the
same standard as today, the road might need to be widened by a similar forty to fifty percent-perhaps extra lane of traffic for the pedestrian to cross. In man cases, to accommodate the foreseeable future demand would destroy the character of the whole urban environment, and is clearly unacceptable.
the traffic problem is of world-wide concern, but different countries are obviously at different stages in the traffic escalation-with America in the lead, while a county has few roads and a relatively low problem, as soon as the country is opened up by a road system, the standard of living and the demand for motor transport both rise, gathering momentum rapidly. eventually-and the stage at which this happens is open to considerable debate-the demand for cars, buses and lorries become satiated. the stage is known as saturation level.
For comparison ,car ownership figures in different countries in 1970 were: India 0.01 cars/person
Israel 0.05cars/person
Japan 0.09 cars/person
Ireland 0.13 cars/person
Netherlands 0.20 cars/person
Great Britain 0.21 cars/person
West Germany 0.23 cars/person
Australia 0.31 cars/person
USA 0.44 cars/person
But the growth in vehicle ownership is only part of the overall traffic problem. obviously,if a country has unlimited roads of extreme width, the traffic problem would not rise. no country in the world could meet this requirement: apart from anything else, it would not make economic for each vehicle using the roads. This figure is decreasing steadily.
Three possible solutions
The basic problem of traffic is therefore simple-an ever-increasing number of vehicles seeking to use too little roade space. the solution to the problem-is else a not-too-difficult choice from three possiblilities:
build, sufficient roads of sufficient size to cope with the demand.
Restrict the demand for roads by restricting the numbers of licensed vehicles.
A compromise between (a) and (b) build some extra roads, using the and the existing road network to their full potential, and at the same time apply some restraint measures, limiting, the increase in demand as far as possible.
With no visible end to the demand yet in sight, and 216 with modern road-making costs ranging around ￡1 million per kilometer cost of building roads in Britain to cope with an unrestricted demand would be far too great. added to this, such clossal use of space in a crowed island cannot be, seriously considered. in Los Angeles, a city built around the parking space for, the automobile. our citie are already largely built-and no one would consider ruining their character by pulling them down and rebuilding around the car, thus the first possible soluting is rule out.
Even today,in an age of at least semi-affluence in most of the Western World, the car is still to some extent a status symbol, a symbol of prestige.every family wants to own one, and takes steps saving or borrowing-to get one. as incomes and standards rise the second car becomes the target. any move to restrict the acquisition of the private car would be most unpopular-and politically unlikely.
For many purpose the flexibility of the private car-conceptually affording door-to-door personal transport is ideal, and its use can be accommodate. for the mass, movement of people along specific corridors within a limited period of time-i.e.. particularly the journey to work it may be less easily accommodated. other transport mode may be more efficient. some sort of compromise solution is the inevitable answer to the basic traffic problem .it is in the execution of the compromise solution that, traffic engineering comes into its own. traffic engineering ensures that any new facilities are not over-deigned and are correctly located to meet the demand. it ensures that the existing facilities are fully used, in the most efficient manner. the fulfillment of these duties may entail the selective throttling of demand: making the use of the car less attractive in the peak periods in order that the limited road space can be more efficiently used by public transport.
Such restraint measures will often be accompanied by improvements in the public transport services, to accommodate the extra demand for them.
Prestressed Concrete Bridges
Prestressed concrete has been used extensively in U.S. bridge construction since its first Introduction from Europe in the late 1940s. Literally thousands of highway bridges of both precast, prestressed concrete and cast-in-place post-tensioned concrete has been constructed in the United States. Railroad bridges utilizing prastressed concrete have become common as well. The use and evolution of prastressed concrete bridges is expected to continue in the years ahead.
Short-span Bridges
Short-span bridges will be assumed to have a maximum of 45 ft (13.7m).It should be understood that this is an arbitrary figure, and there is no definite line of demarcation between short, moderate, and long spans in highway bridges. Short-span bridges are most efficiently made of precast ,prestressed-concrete hollow slabs, I-beams, solid slabs or cast-place solid slabs. and T-beams of relatively generous proportions.
Precast solid slabs are most economical when used on very short spans. The slabs can be made in any convenient width,but widths of 3 or 4 ft (0.9 to 1.2m) have been common.Keys frequently are cast in the longitudinal sides of the precast units. After the slabs have been erected and the joints between the slabs have been filled with concrete, the keys transfer live load shear forces between the adjacent slabs.
Precast hollow slabs used in short-span bridges may have round or square voids. They too are generally made in units 3 to 4 ft (0.9 to 1.2 m) wide with thicknesses from 18 to 27 in (45.7 to 68.6cm). Precast hollow slabs can be made in any convenient width and depth, and frequently are used in bridges having spans from 20 to 50 ft (6.1 to 15.2m). Longitudinal shear keys are used in the joints between adjacent hollow slabs in the same way as with solid slabs. Hollow slabs may or may not be used with a composite, cast-in-place concrete topping an accecptable appearance and levelness.
Transverse reinforcement normally is provided in precast concrete bridge superstructures for the purpose of tying the structure together in the transverse direction. Well-designed ties ensure that the individual longitudinal members
forming
the superstructure will act as a unit under the effects of the live load. In slab bridge construction, transverse ties most frequently consist of threaded steel bars placed through small holes formed transversely through the member during fabrication. Nuts frequently are used as fasteners at each end of the bars. In some instances, the transverse ties consist of post tensioned tendons placed, stressed, and grouted after the slabs have been erected. The transverse tie usually extends from one side of the bridge to the other.
The shear forces imposed on the stringers in short-span bridges frequently are too large to be resisted by the concrete alone. Hence, shear reinforcement normally is required. The amount of shear reinforcement required may be relatively large if the webs of the stringers are relatively thin.
Concrete diaphragms, reinforced with post-tensioned reinforcement or nonprestressed reinforcement, normally are provided transversely at the ends and at intermediate locations along the span in stringer-type bridges. The disaphragms ensure the lateral-distribution of the live load to the various stringers and prevent individual stringers from displacing or rotating significantly with respect to the adjacent stringers.
No generalities will be made here about the relative cost of each of the above types of construction; construction costs are a function of many variables which prohibit meaningful generalizations. However, it should be noted that the stringer type of construction requires a considerably greater construction depth that is required for solid, hollow, or channel slab bridge superstructures. Stringer construction does not require a separate wearing surface, as do the precast slab types of construction, unless precast slabs are used to span between the stringers in lieu of the more commonly used cast-in-place reinforced concrete deck. Stringer construction frequently requires smaller quantities of superstructure materials than do slab bridges (unless the spans are very short). The construction time needed to complete a bridge after the precast members have been erected is greater with stringer framing than with the slab type of framing.
Bridges Of Moderate Span
Again for the purpose of this discussion only, moderate spans for bridges of prestressed concrete are defined as being from 45 to 80 ft (13.7 to 24.4m). Prestressed concrete bridges in this span range generally can be divided into two
types: stringer-type bridges and slab-type bridges. The majority of the precast prestressed concrete bridges constructed in the United States have been stringer bridges using I-shaped stringers, but a large number of precast prestressed concrete bridges have been constructed with precast hollow-box girders (sometimes also called stringers). Cast-in-place post-tensioned concrete has been used extensively in the construction of hollow-box girder bridges-a form of construction that can be considered to be a slab bridge.
Stringer bridges, which employ a composite, cast-in-place deck slab, have been used in virtually all parts of the United States. These stringers normally are used at spacing s of about 5 to 6 ft (1.5 to 1.8m). The cast-in-place deck is generally from 6.0 to 8.0 in(15.2 to 20.3cm) in thickness. This type of framing is very much the same as that used on composite-stringer construction for short-span bridges.
Diaphram details in moderate-span bridges are generally similar to those of the short spans, with the exception that two or three interior diaphragms sometime are used, rather than just one at midspan as in the short-span bridge.
As in the case of short-span bridges, the minimum depth of construction in bridges of moderate span is obtained by using slab construction, which may be either solid – or hollow – box in cross section. Average construction depths are requires when stringers with large flanges are used in composite construction, and large construction depths are required when stringers with small bottom flanges are used. Composite construction may be developed through the use of cast-in-place concrete decks or with precast concrete decks. Lower quantities of materials normally are required with composite construction , and the dead weight of the superstructure normally is less for stringer construction than for slab construction.
Long-Span Bridges
Prestressed concrete bridges having spans of the order of 100ft are of the same general types of construction as structures having moderate span lengths, with the single exception that solid slabs are not used for long spans. The stringer spacings are frequently greater (with stringers at 7 to 9 ft) as the span lengths of bridges increase. Because of dead weight considerations, precast hollow-box construction generally is employed for spans of this length only when the depth of construction must be minimized. Cast-in-place post-tensioned hollow-box
bridges with simple and continuous spans frequently are used for spans on the order of 100 ft and longer.
Simple, precast, prestressed stringer construction would be economical in the United States in the spans up to 300 ft under some conditions. However, only limited use has been made of this type of construction on spans greater than 100 ft. For very long simple spans, the advantage of precasting frequently is nullified by the difficulties involved in handling, transporting, and erecing the girders, which may have depths as great as 10 ft and weigh over 200 tons. The exceptions to this occur on large projects where all of the spans are over water of sufficient depth and character that precast beams can be handled with floating equipment, when custom girder launchers can be used, and when segmental construction techniques can be used.
The use of cast-in-place , post-tensioned, box-girder bridges has been extensive. Although structures of these types occasionally are used for spans less than 100ft, they more often are used for spans in excess of 100 ft and have been used in structures
Having spans in excess of 300 ft. Structurally efficient in flexure, especially for continuous bridges, the box girder is torsionally stiff and hence an excellent type of structure for use on bridges that have horizontal curvature. Some governmental agencies use this form of construction almost exclusively in urban areas where appearance from underneath the superstructure, as well as from the side, is considered important.
交通工程
介绍什么是交通工程
交通工程仍然是在土木工程的总的界限内的一种相对新的训练。虽然如此交通工程已经部分计划.可是，训练不同义。计划的运输涉及计划，功能的设计，为运输的任何方式熟练的经营管理，为了为人和货物的安全，迅速，舒适，方便，节约和环境运动作准备。在那宽的范围内，交通工程关于道路，道路网络，端子点，关于土地和他们的有运输的其他方式的关系处理那些功能。那些定义，那些定义，基于那些美国研究院的1976个工程师完整的运输比较英国土木工程的设立，处理计划的交通和道路的设计，空地发展和停放设备并且与一起要提供安全，方便和节约运动的车辆和行人的掌握的交通。那些训练的定义变得清楚：那些方法学连续发展并且变得越来越科学。早的经验法则技术正消失。
交通问题
这些纪律不成熟：存在着很大的问题并且仍然增长。在1920辆机动车的总数，在英国批准是650，000.50 年以后那些可比较数字在14，950，000一增长系数的23 倍.在近年成长率已经有点减弱，但是这仍然是相当多的1955 6,466,000
1960 9,439,000
1965 12,938,000
1970 14,950,000
1974 17,247,000
为了看见在每天条件的问题，考虑高速公路。如果提出趋势，继续，预计在交通在这道路上的如此的今后15 年内将以百分之40 的大约增加到百分之50 .如果交通的这被增加的卷是成为在与今天相同的标准的计量，行人穿过，道路可能通过相似的百分之40 到50 或许交通的额外的小路需要加宽。在人情况里，接受可预知的将来的需求将破坏整个都市的环境的性格,并且显然不可接受。交通问题具有世界范围关心，但是不同的国家显而易见在在交通与逐步上升的遥遥领先美国里的不同的阶段，当一个县有很少道路和相对低的问题时，那些国家一被打开以道路系统，那些生活水平和那些需求就适合电动机运输都上升,,迅速抽打冲力.最终和舞台对这发生哪个易受到相当多辩论需求适合变得满足的小汽车，公共汽车和运货汽车。.这一阶段被称为饱和阶段
。对比较来说，汽车所有权把不同国家计算进去在1970年
印度0.01 辆/人
以色列0.05辆/人
日本0.09辆/人
爱尔兰0.13辆/人
荷兰0.20辆/人
英国0.21辆/人
西德0.23辆/人
澳大利亚0.31辆/人
美国0.44辆/人
但是在车辆所有权方面的发展只是总的交通问题的一部分.显而易见，如果一个国家有极端的宽度无限的道路，交通问题将不上升。世界上的没有国家能满足这要求：除其它任何事情外，不将适合每辆车辆使用道路做经济。这个数字正稳定地减少。
3 个可能的解决办法
基本问题的交通因此简单一不断增加车辆的数量想办法使用太少道路空间。解决的方法问题其他一不也困难选择从3 可能性：
建造，应付需求的足够的大小的足够的道路。
通过限制批准的车辆的数量限制对道路的需求。
在(A)和(b)之间的妥协建造一些额外的道路，使用和那些已经存在的道路网络兑一他们的全部潜能，并且同时使用一些抑制测量，限制，尽可能需求增加。
没有需求的可见的结局可以看见，以及216 由于在英国在大楼道路的每公里费用100万英镑左右范围应付一个无限制的需求的现代使道路的费用将太大。增加这项费用，如此狭小，喧嚣的岛一样的使用空间不能被认真地考虑。.在洛杉矶，城市在那些停车空地到处建造适合，那些汽车。我们的城市已经被基本上建造，没有人将考虑通过在汽车周围使他们虚弱和再造毁坏他们的性格，因此第一个可能的解决办法就是规章。
即使今天，在一个至少半富裕的时代在大多数西方的世界里，汽车仍
然在某种程度上是身份象征，一个威望的象征。每家庭想要拥有一辆车，并且采取措施救或者借得到一辆。当收入和标准上涨时，二手车成为目标。限制获得私人汽车的任何行动将是非常不受欢迎的和在政治上不太可能。
很多目的个人运输理想，它使用可能接受的买得起挨门挨户的私人汽车观念的灵活性。很多目的个人运输理想，它使用可能适应的买得起挨门挨户的私人汽车观念的灵活性.那些群众，运动的人以来沿着具体走廊在有限时期内即.特别要设法安排的那些旅行可能被较少容易容纳。其他运输方式可能更有效率。有点妥协解决办法是不可避免基本的交通问题的答案。这是执行这个妥协解决办法那，交通工程得到它所应得。交通工程保证任何新设备没被过于屈尊正确地位于满足需求。它保证现有的设备被完全使用，以非常有效率的方式。.那些履行的这些职责需要那些选择需求的调节可能：在那些山峰时期内使那些使用的那些不那么有吸引力的汽车，为了公共运输可能更有效地使用有限的道路空间。
这样的抑制措施经常伴随着在公开传送服务方面的改进，以便接受对他们的额外的需求。
预应力混凝土桥梁
预应力混凝土自20世纪90年代末期首次在欧洲发明以来，被广泛应用于美国桥梁的建设。在美国，上千的公路桥梁建设中使用了后张预制预应力混凝土和现浇混凝土。而且，预应力混凝土在铁路桥梁中的应用也变的非常普及。并且，近些年来预应力混凝土桥梁在不断的应用和改进。
短跨径桥梁：
跨径小于13.7m的桥梁，称为短跨径桥梁，这是一个很粗略的数字，因为在公路桥梁中，短跨、中跨和大跨没有一个严格的划分界限。短跨桥梁中广泛使用预制的预应力混凝土空心板、I字梁、实心板、现浇实心板，还有占有很大使用比例的T形梁。
预制实心板用于非常短的跨径是很经济的。板可被作成任意宽度一般使用0.9~1.2m,在预制件的长度方向使用剪力键，在填筑混凝土以后，剪力键用来传递两相邻板块间的活载剪力。
预制空心板有圆孔和方孔，通常用于0.9~1.2m宽，45.7~68.6cm厚的预制件中，它也可被做成任意的宽度和高度，一般用在跨径为6.1~15.2m的桥梁中。纵向的剪力键也象实心板一样用在两相邻板的节点处。预制空心板可以使用在现浇的复合上部结构中，此时要求使用整平层，以获得满意的外观
和平整度。
横向加固用来使预应力混凝土桥梁的上部结构在横桥方向紧密连接在一起。设计良好的横向联系能保证组成上部结构的单个纵向构件在活载作用下呈整体而工作。在板式桥梁结构中，横向联系是通过在制作过程中使用螺纹钢筋在横向穿过每个单元的小孔，并在钢筋端部使用螺母锚固。在有些情况下，横向联系由后张法预应力钢丝束构成，板安装好后，设置钢筋，加预应力，再灌孔。横向联系通常贯穿桥梁的整个断断，及从桥梁横向的一侧到另一侧。
在短跨度桥中，施加于梁上的剪力很大以致于不能被混凝土单独承受，因此，就需要加强抗剪能力，设置剪力钢筋。如果板厚很薄，需要的剪力钢筋数量也就越多。
混凝土横隔板由后张的钢筋和非预应力钢筋进行加固，通常设置在梁式桥的跨中截面和梁端位置。横隔板可以确保活载在不同梁上的横向分布，同时也限制了相邻梁之间的相对转角和位移，使各片梁组成整体工作状态。
每种上部结构形式的相对造价并没有普遍性，结构造价是多方面不同的参数所决定的。我们可以看的出，梁式结构比实心板、空心板、槽形板上部结构所需的截面高度大。梁式结构和预制板式结构一样，不需要单独的磨耗层，除非是用梁取代现浇钢筋混凝土板时。梁式桥梁结构所需的上部结构材料数量要比板式桥梁的要小（除非跨径非常小）。在各个预制件浇注完成以后，梁式桥梁的施工时间要比板式桥的施工时间要长。
中等跨径桥梁：
跨径从13.7`24.4m的预应力混凝土桥梁称作中等跨径桥梁。此时，预应力混凝土桥梁可以分成两种形式：梁式桥和板式桥。在美国，梁式桥中主要使用I字型梁，板式梁中主要使用预制的空心箱梁。在空心箱梁桥的施工中采用后张法的现浇混凝土，这种箱梁桥也被称作是一种板式梁桥。
梁式桥梁采用合成的、现浇顶板结构，在美国被广泛的应用。梁的宽度通常是1.5`1.8m,现浇顶板厚度通常是15.2~20.3cm,这种框架形式非常类似于在在短跨桥梁中使用的复合梁式结构。
中等跨径桥中，横隔板详图一般与短跨桥中的相似，有时需要设置两、三块中间横隔板，而不是像短跨桥中只在跨中设置一块横隔板。
在中等跨径桥中的结构最小高度可以达到使用板式结构时的高度尺寸，在相交位置作成实心或空心箱。在复合式结构中，若采用大翼缘梁时需要一般的建筑高度，若采用小的底部翼缘时就需要大的建筑高度。复合结构可以
采用现浇混凝土板或预制的混凝土板，它所需要的材料数量少，所以，梁式结构的上部恒载要比板式结构的小。
大跨度桥梁：
预应力混凝土桥梁跨度超过100英尺，即被认为是大跨度范畴，实心板不用于大跨桥梁中。随着桥梁跨度的增加，梁体的截面尺寸也要增加。由于考虑恒载自重，当建筑高度要求最小时，采用空心箱梁结构。在100英尺或更大的跨度时，经常采用后张法的现浇空心箱式简支梁和连续梁。
在美国，预制简支预应力梁达到跨径300英尺，实践证明，这种结构是很经济的。但是，目前很有限地应用于100英尺以上的跨度。对于很长跨径的简支梁，梁高超过10英尺，重量超过200吨，此时，由于在运输与安装的困难，使得这种预浇的优势显得微不足道。在大型工程中，当跨河位置处于水深较大的地方时预制梁可以用浮运设备安装，这时，普通的梁起动装置和分段施工技术也被应用，它的经济效益非常明显。
现浇的后张法箱形梁被广泛使用。虽然这些类型的结构偶尔用于不到100 英尺的跨度，他们更经常用于跨度超过100 英尺并且在跨度超过300 英尺的结构中也被使用。箱形梁抵抗弯曲的结构效率高（特别是连续箱梁更始如此），抗扭刚度大，因此，它用于弯桥中是一种极好的结构形式。一些政府机构在郊区桥梁建设中，考虑到从下部和侧面来选择上部结构时，也优先使用箱梁桥。
外文出处： 《Exploiting Software How to Break Code》By Greg Hoglund, Gary McGraw Publisher : Addison Wesley Pub Date : February 17, 2004 ISBN : 0-201-78695-8 译文标题： JDBC接口技术 译文： JDBC是一种可用于执行SQL语句的JavaAPI（ApplicationProgrammingInterface应用程序设计接口）。它由一些Java语言编写的类和界面组成。JDBC为数据库应用开发人员、数据库前台工具开发人员提供了一种标准的应用程序设计接口，使开发人员可以用纯Java语言编写完整的数据库应用程序。 一、ODBC到JDBC的发展历程 说到JDBC，很容易让人联想到另一个十分熟悉的字眼“ODBC”。它们之间有没有联系呢？如果有，那么它们之间又是怎样的关系呢？ ODBC是OpenDatabaseConnectivity的英文简写。它是一种用来在相关或不相关的数据库管理系统（DBMS）中存取数据的，用C语言实现的，标准应用程序数据接口。通过ODBCAPI，应用程序可以存取保存在多种不同数据库管理系统（DBMS）中的数据，而不论每个DBMS使用了何种数据存储格式和编程接口。 1．ODBC的结构模型 ODBC的结构包括四个主要部分：应用程序接口、驱动器管理器、数据库驱动器和数据源。应用程序接口：屏蔽不同的ODBC数据库驱动器之间函数调用的差别，为用户提供统一的SQL编程接口。 驱动器管理器：为应用程序装载数据库驱动器。 数据库驱动器：实现ODBC的函数调用，提供对特定数据源的SQL请求。如果需要，数据库驱动器将修改应用程序的请求，使得请求符合相关的DBMS所支持的文法。 数据源：由用户想要存取的数据以及与它相关的操作系统、DBMS和用于访问DBMS的网络平台组成。 虽然ODBC驱动器管理器的主要目的是加载数据库驱动器，以便ODBC函数调用，但是数据库驱动器本身也执行ODBC函数调用，并与数据库相互配合。因此当应用系统发出调用与数据源进行连接时，数据库驱动器能管理通信协议。当建立起与数据源的连接时，数据库驱动器便能处理应用系统向DBMS发出的请求，对分析或发自数据源的设计进行必要的翻译，并将结果返回给应用系统。 2．JDBC的诞生 自从Java语言于1995年5月正式公布以来，Java风靡全球。出现大量的用java语言编写的程序，其中也包括数据库应用程序。由于没有一个Java语言的API，编程人员不得不在Java程序中加入C语言的ODBC函数调用。这就使很多Java的优秀特性无法充分发挥，比如平台无关性、面向对象特性等。随着越来越多的编程人员对Java语言的日益喜爱，越来越多的公司在Java程序开发上投入的精力日益增加，对java语言接口的访问数据库的API 的要求越来越强烈。也由于ODBC的有其不足之处，比如它并不容易使用，没有面向对象的特性等等，SUN公司决定开发一Java语言为接口的数据库应用程序开发接口。在JDK1．x 版本中，JDBC只是一个可选部件，到了JDK1．1公布时，SQL类包（也就是JDBCAPI）
PA VEMENT PROBLEMS CAUSED BY COLLAPSIBLE SUBGRADES By Sandra L. Houston,1 Associate Member, ASCE (Reviewed by the Highway Division) ABSTRACT: Problem subgrade materials consisting of collapsible soils are com- mon in arid environments, which have climatic conditions and depositional and weathering processes favorable to their formation. Included herein is a discussion of predictive techniques that use commonly available laboratory equipment and testing methods for obtaining reliable estimates of the volume change for these problem soils. A method for predicting relevant stresses and corresponding collapse strains for typical pavement subgrades is presented. Relatively simple methods of evaluating potential volume change, based on results of familiar laboratory tests, are used. INTRODUCTION When a soil is given free access to water, it may decrease in volume, increase in volume, or do nothing. A soil that increases in volume is called a swelling or expansive soil, and a soil that decreases in volume is called a collapsible soil. The amount of volume change that occurs depends on the soil type and structure, the initial soil density, the imposed stress state, and the degree and extent of wetting. Subgrade materials comprised of soils that change volume upon wetting have caused distress to highways since the be- ginning of the professional practice and have cost many millions of dollars in roadway repairs. The prediction of the volume changes that may occur in the field is the first step in making an economic decision for dealing with these problem subgrade materials. Each project will have different design considerations, economic con- straints, and risk factors that will have to be taken into account. However, with a reliable method for making volume change predictions, the best design relative to the subgrade soils becomes a matter of economic comparison, and a much more rational design approach may be made. For example, typical techniques for dealing with expansive clays include: (1) In situ treatments with substances such as lime, cement, or fly-ash; (2) seepage barriers and/ or drainage systems; or (3) a computing of the serviceability loss and a mod- ification of the design to "accept" the anticipated expansion. In order to make the most economical decision, the amount of volume change (especially non- uniform volume change) must be accurately estimated, and the degree of road roughness evaluated from these data. Similarly, alternative design techniques are available for any roadway problem. The emphasis here will be placed on presenting economical and simple methods for: (1) Determining whether the subgrade materials are collapsible; and (2) estimating the amount of volume change that is likely to occur in the 'Asst. Prof., Ctr. for Advanced Res. in Transp., Arizona State Univ., Tempe, AZ 85287. Note. Discussion open until April 1, 1989. To extend the closing date one month,
毕业设计（论文）外文文献翻译 文献、资料中文题目：软件开发概念和设计方法文献、资料英文题目： 文献、资料来源： 文献、资料发表（出版）日期： 院（部）： 专业： 班级： 姓名： 学号： 指导教师： 翻译日期： 2017.02.14
外文资料原文 Software Development Concepts and Design Methodologies During the 1960s, ma inframes and higher level programming languages were applied to man y problems including human resource s yste ms,reservation s yste ms, and manufacturing s yste ms. Computers and software were seen as the cure all for man y bu siness issues were some times applied blindly. S yste ms sometimes failed to solve the problem for which the y were designed for man y reasons including: ?Inability to sufficiently understand complex problems ?Not sufficiently taking into account end-u ser needs, the organizational environ ment, and performance tradeoffs ?Inability to accurately estimate development time and operational costs ?Lack of framework for consistent and regular customer communications At this time, the concept of structured programming, top-down design, stepwise refinement，and modularity e merged. Structured programming is still the most dominant approach to software engineering and is still evo lving. These failures led to the concept of "software engineering" based upon the idea that an engineering-like discipl ine could be applied to software design and develop ment. Software design is a process where the software designer applies techniques and principles to produce a conceptual model that de scribes and defines a solution to a problem. In the beginning, this des ign process has not been well structured and the model does not alwa ys accurately represent the problem of software development. However,design methodologies have been evolving to accommo date changes in technolog y coupled with our increased understanding of development processes. Whereas early desig n methods addressed specific aspects of the
桥梁工程毕业设计外文翻译箱梁
西南交通大学本科毕业设计（论文） 外文资料翻译 年级: 学号: 姓名: 专业: 指导老师:
6 月
外文资料原文： 13 Box girders 13.1 General The box girder is the most ?exible bridge deck form. It can cover a range of spans from25 m up to the largest non-suspended concrete decks built, of the order of 300 m. Single box girders may also carry decks up to 30 m wide. For the longer span beams, beyond about 50 m, they are practically the only feasible deck section. For the shorter spans they are in competition with most of the other deck types discussed in this book. The advantages of the box form are principally its high structural ef?ciency (5.4), which minimises the prestress force required to resist a given bending moment, and its great torsional strength with the capacity this gives to re-centre eccentric live loads, minimising the prestress required to carry them.
姓名： 学号： 10447425 X X 大学 毕业设计（论文）外文翻译 （2014届） 外文题目Developments in excavation bracing systems 译文题目开挖工程支撑体系的发展 外文出处Tunnelling and Underground Space Technology 31 (2012) 107–116 学生XXX 学院XXXX 专业班级XXXXX 校内指导教师XXX 专业技术职务XXXXX 校外指导老师专业技术职务 二○一三年十二月
开挖工程支撑体系的发展 1.引言 几乎所有土木工程建设项目（如建筑物，道路，隧道，桥梁，污水处理厂，管道，下水道）都涉及泥土挖掘的一些工程量。往往由于由相邻的结构，特性线，或使用权空间的限制，必须要一个土地固定系统，以允许土壤被挖掘到所需的深度。历史上，许多挖掘支撑系统已经开发出来。其中，现在比较常见的几种方法是：板桩，钻孔桩墙，泥浆墙。 土地固定系统的选择是由技术性能要求和施工可行性（例如手段，方法）决定的，包括执行的可靠性，而成本考虑了这些之后，其他问题也得到解决。通常环境后果（用于处理废泥浆和钻井液如监管要求）也非常被关注（邱阳、1998）。 土地固定系统通常是建设项目的较大的一个组成部分。如果不能按时完成项目，将极大地影响总成本。通常首先建造支撑，在许多情况下，临时支撑系统是用于支持在挖掘以允许进行不断施工，直到永久系统被构造。临时系统可以被去除或留在原处。 打桩时，因撞击或振动它们可能会被赶入到位。在一般情况下，振动是最昂贵的方法，但只适合于松散颗粒材料，土壤中具有较高电阻（例如，通过鹅卵石）的不能使用。采用打入桩系统通常是中间的成本和适合于软沉积物（包括粘性和非粘性），只要该矿床是免费的鹅卵石或更大的岩石。 通常，垂直元素（例如桩）的前安装挖掘工程和水平元件（如内部支撑或绑回）被安装为挖掘工程的进行下去，从而限制了跨距长度，以便减少在垂直开发弯矩元素。在填充情况下，桩可先设置，从在斜坡的底部其嵌入悬挑起来，安装作为填充进步水平元素（如搭背或土钉）。如果滞后是用来保持垂直元素之间的土壤中，它被安装为挖掘工程的进行下去，或之前以填补位置。 吉尔- 马丁等人（2010）提供了一个数值计算程序，以获取圆形桩承受轴向载荷和统一标志（如悬臂桩）的单轴弯矩的最佳纵筋。他们开发的两种优化流程：用一个或两个直径为纵向钢筋。优化增强模式允许大量减少的设计要求钢筋的用量，这些减少纵向钢筋可达到50％相对传统的，均匀分布的加固方案。 加固桩集中纵向钢筋最佳的位置在受拉区。除了节约钢筋，所述非对称加强钢筋图案提高抗弯刚度，通过增加转动惯量的转化部分的时刻。这种增加的刚性可能会在一段时间内增加的变形与蠕变相关的费用。评估相对于传统的非对称加强桩的优点，对称，钢筋桩被服务的条件下全面测试来完成的，这种试验是为了验证结构的可行性和取得的变形的原位测量。 基于现场试验中，用于优化的加强图案的优点浇铸钻出孔（CIDH）在巴塞罗那的
外文翻译 专业机械设计制造及其自动化学生姓名刘链柱 班级机制111 学号1110101102 指导教师葛友华
外文资料名称： Design and performance evaluation of vacuum cleaners using cyclone technology 外文资料出处：Korean J. Chem. Eng., 23(6), (用外文写) 925-930 (2006) 附件： 1.外文资料翻译译文 2.外文原文
应用旋风技术真空吸尘器的设计和性能介绍 吉尔泰金，洪城铱昌，宰瑾李， 刘链柱译 摘要：旋风型分离器技术用于真空吸尘器 - 轴向进流旋风和切向进气道流旋风有效地收集粉尘和降低压力降已被实验研究。优化设计等因素作为集尘效率，压降，并切成尺寸被粒度对应于分级收集的50％的效率进行了研究。颗粒切成大小降低入口面积，体直径，减小涡取景器直径的旋风。切向入口的双流量气旋具有良好的性能考虑的350毫米汞柱的低压降和为1.5μm的质量中位直径在1米3的流量的截止尺寸。一使用切向入口的双流量旋风吸尘器示出了势是一种有效的方法，用于收集在家庭中产生的粉尘。 摘要及关键词：吸尘器; 粉尘; 旋风分离器 引言 我们这个时代的很大一部分都花在了房子，工作场所，或其他建筑，因此，室内空间应该是既舒适情绪和卫生。但室内空气中含有超过室外空气因气密性的二次污染物，毒物，食品气味。这是通过使用产生在建筑中的新材料和设备。真空吸尘器为代表的家电去除有害物质从地板到地毯所用的商用真空吸尘器房子由纸过滤，预过滤器和排气过滤器通过洁净的空气排放到大气中。虽然真空吸尘器是方便在使用中，吸入压力下降说唱空转成比例地清洗的时间，以及纸过滤器也应定期更换，由于压力下降，气味和细菌通过纸过滤器内的残留粉尘。 图1示出了大气气溶胶的粒度分布通常是双峰形，在粗颗粒（>2.0微米）模式为主要的外部来源，如风吹尘，海盐喷雾，火山，从工厂直接排放和车辆废气排放，以及那些在细颗粒模式包括燃烧或光化学反应。表1显示模式，典型的大气航空的直径和质量浓度溶胶被许多研究者测量。精细模式在0.18?0.36 在5.7到25微米尺寸范围微米尺寸范围。质量浓度为2?205微克，可直接在大气气溶胶和 3.85至36.3μg/m3柴油气溶胶。
附录A 英文文献 Drive Axle All vehicles have some type of drive axle/differential assembly incorporated into the driveline. Whether it is front, rear or four wheel drive, differentials are necessary for the smooth application of engine power to the road. Powerflow The drive axle must transmit power through a 90°angle. The flow of power in conventional front engine/rear wheel drive vehicles moves from the engine to the drive axle in approximately a straight line. However, at the drive axle, the power must be turned at right angles (from the line of the driveshaft) and directed to the drive wheels. This is accomplished by a pinion drive gear, which turns a circular ring gear. The ring gear is attached to a differential housing, containing a set of smaller gears that are splined to the inner end of each axle shaft. As the housing is rotated, the internal differential gears turn the axle shafts, which are also attached to the drive wheels. Rear-wheel drive Rear-wheel-drive vehicles are mostly trucks, very large sedans and many sports car and coupe models. The typical rear wheel drive vehicle uses a front mounted engine and transmission assemblies with a driveshaft coupling the transmission to the rear drive axle. Drive in through the layout of the bridge, the bridge drive shaft arranged vertically in the same vertical plane, and not the drive axle shaft, respectively, in their own sub-actuator with a direct connection, but the actuator is located at the front or the back of the adjacent shaft
I / 11 本科毕业设计外文翻译 <2018届） 论文题目基于WEB 的J2EE 的信息系统的方法研究 作者姓名[单击此处输入姓名] 指导教师[单击此处输入姓名] 学科(专业 > 所在学院计算机科学与技术学院 提交日期[时间 ]
基于WEB的J2EE的信息系统的方法研究 摘要：本文介绍基于工程的Java开发框架背后的概念，并介绍它如何用于IT 工程开发。因为有许多相同设计和开发工作在不同的方式下重复，而且并不总是符合最佳实践，所以许多开发框架建立了。我们已经定义了共同关注的问题和应用模式，代表有效解决办法的工具。开发框架提供：<1）从用户界面到数据集成的应用程序开发堆栈；<2）一个架构，基本环境及他们的相关技术，这些技术用来使用其他一些框架。架构定义了一个开发方法，其目的是协助客户开发工程。 关键词：J2EE 框架WEB开发 一、引言 软件工具包用来进行复杂的空间动态系统的非线性分析越来越多地使用基于Web的网络平台，以实现他们的用户界面，科学分析，分布仿真结果和科学家之间的信息交流。对于许多应用系统基于Web访问的非线性分析模拟软件成为一个重要组成部分。网络硬件和软件方面的密集技术变革[1]提供了比过去更多的自由选择机会[2]。因此，WEB平台的合理选择和发展对整个地区的非线性分析及其众多的应用程序具有越来越重要的意义。现阶段的WEB发展的特点是出现了大量的开源框架。框架将Web开发提到一个更高的水平，使基本功能的重复使用成为可能和从而提高了开发的生产力。 在某些情况下，开源框架没有提供常见问题的一个解决方案。出于这个原因，开发在开源框架的基础上建立自己的工程发展框架。本文旨在描述是一个基于Java的框架，该框架利用了开源框架并有助于开发基于Web的应用。通过分析现有的开源框架，本文提出了新的架构，基本环境及他们用来提高和利用其他一些框架的相关技术。架构定义了自己开发方法，其目的是协助客户开发和事例工程。 应用程序设计应该关注在工程中的重复利用。即使有独特的功能要求，也
（ 二 〇 一 二 年 六 月 外文文献及翻译 题 目： About Buiding on the Structure Design 学生姓名： 学 院：土木工程学院 系 别：建筑工程系 专 业：土木工程(建筑工程方向) 班 级：土木08-4班 指导教师：
英文原文： Building construction concrete crack of prevention and processing Abstract The crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure. Keyword:Concrete crack prevention processing Foreword Concrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the
Optimum blank design of an automobile sub-frame Jong-Yop Kim a ,Naksoo Kim a,*,Man-Sung Huh b a Department of Mechanical Engineering,Sogang University,Shinsu-dong 1,Mapo-ku,Seoul 121-742,South Korea b Hwa-shin Corporation,Young-chun,Kyung-buk,770-140,South Korea Received 17July 1998 Abstract A roll-back method is proposed to predict the optimum initial blank shape in the sheet metal forming process.The method takes the difference between the ?nal deformed shape and the target contour shape into account.Based on the method,a computer program composed of a blank design module,an FE-analysis program and a mesh generation module is developed.The roll-back method is applied to the drawing of a square cup with the ˉange of uniform size around its periphery,to con?rm its validity.Good agreement is recognized between the numerical results and the published results for initial blank shape and thickness strain distribution.The optimum blank shapes for two parts of an automobile sub-frame are designed.Both the thickness distribution and the level of punch load are improved with the designed blank.Also,the method is applied to design the weld line in a tailor-welded blank.It is concluded that the roll-back method is an effective and convenient method for an optimum blank shape design.#2000Elsevier Science S.A.All rights reserved. Keywords:Blank design;Sheet metal forming;Finite element method;Roll-back method
毕业设计（论文） 外文翻译 题目西安市水源工程中的 水电站设计 专业水利水电工程 班级 学生 指导教师 2016年
研究钢弧形闸门的动态稳定性 牛志国 河海大学水利水电工程学院，中国南京，邮编210098 nzg_197901@https://www.doczj.com/doc/2a17990267.html,，niuzhiguo@https://www.doczj.com/doc/2a17990267.html, 李同春 河海大学水利水电工程学院，中国南京，邮编210098 ltchhu@https://www.doczj.com/doc/2a17990267.html, 摘要 由于钢弧形闸门的结构特征和弹力，调查对参数共振的弧形闸门的臂一直是研究领域的热点话题弧形弧形闸门的动力稳定性。在这个论文中，简化空间框架作为分析模型，根据弹性体薄壁结构的扰动方程和梁单元模型和薄壁结构的梁单元模型，动态不稳定区域的弧形闸门可以通过有限元的方法，应用有限元的方法计算动态不稳定性的主要区域的弧形弧形闸门工作。此外，结合物理和数值模型，对识别新方法的参数共振钢弧形闸门提出了调查，本文不仅是重要的改进弧形闸门的参数振动的计算方法，但也为进一步研究弧形弧形闸门结构的动态稳定性打下了坚实的基础。 简介 低举升力，没有门槽，好流型，和操作方便等优点，使钢弧形闸门已经广泛应用于水工建筑物。弧形闸门的结构特点是液压完全作用于弧形闸门，通过门叶和主大梁，所以弧形闸门臂是主要的组件确保弧形闸门安全操作。如果周期性轴向载荷作用于手臂，手臂的不稳定是在一定条件下可能发生。调查指出:在弧形闸门的20次事故中，除了极特殊的破坏情况下，弧形闸门的破坏的原因是弧形闸门臂的不稳定;此外，明显的动态作用下发生破坏。例如:张山闸，位于中国的江苏省，包括36个弧形闸门。当一个弧形闸门打开放水时，门被破坏了，而其他弧形闸门则关闭，受到静态静水压力仍然是一样的，很明显，一个动态的加载是造成的弧形闸门破坏一个主要因素。因此弧形闸门臂的动态不稳定是造成弧形闸门(特别是低水头的弧形闸门)破坏的主要原是毫无疑问。
Section 3 Design philosophy, design method and earth pressures 3.1 Design philosophy 3.1.1 General The design of earth retaining structures requires consideration of the interaction between the ground and the structure. It requires the performance of two sets of calculations: 1）a set of equilibrium calculations to determine the overall proportions and the geometry of the structure necessary to achieve equilibrium under the relevant earth pressures and forces; 2）structural design calculations to determine the size and properties of thestructural sections necessary to resist the bending moments and shear forces determined from the equilibrium calculations. Both sets of calculations are carried out for specific design situations (see 3.2.2) in accordance with the principles of limit state design. The selected design situations should be sufficiently Severe and varied so as to encompass all reasonable conditions which can be foreseen during the period of construction and the life of the retaining wall. 3.1.2 Limit state design This code of practice adopts the philosophy of limit state design. This philosophy does not impose upon the designer any special requirements as to the manner in which the safety and stability of the retaining wall may be achieved, whether by overall factors of safety, or partial factors of safety, or by other measures. Limit states (see 1.3.13) are classified into: a) ultimate limit states (see 3.1.3); b) serviceability limit states (see 3.1.4). Typical ultimate limit states are depicted in figure 3. Rupture states which are reached before collapse occurs are, for simplicity, also classified and
7 Rigid-Frame Structures A rigid-frame high-rise structure typically comprises parallel or orthogonally arranged bents consisting of columns and girders with moment resistant joints. Resistance to horizontal loading is provided by the bending resistance of the columns, girders, and joints. The continuity of the frame also contributes to resisting gravity loading, by reducing the moments in the girders. The advantages of a rigid frame are the simplicity and convenience of its rectangular form.Its unobstructed arrangement, clear of bracing members and structural walls, allows freedom internally for the layout and externally for the fenestration. Rig id frames are considered economical for buildings of up to' about 25 stories, above which their drift resistance is costly to control. If, however, a rigid frame is combined with shear walls or cores, the resulting structure is very much stiffer so that its height potential may extend up to 50 stories or more. A flat plate structure is very similar to a rigid frame, but with slabs replacing the girders As with a rigid frame, horizontal and vertical loadings are resisted in a flat plate structure by the flexural continuity between the vertical and horizontal components. As highly redundant structures, rigid frames are designed initially on the basis of approximate analyses, after which more rigorous analyses and checks can be made. The procedure may typically inc lude the following stages: 1. Estimation of gravity load forces in girders and columns by approximate method. 2. Preliminary estimate of member sizes based on gravity load forces with arbitrary increase in sizes to allow for horizontal loading. 3. Approximate allocation of horizontal loading to bents and preliminary analysis of member forces in bents. 4. Check on drift and adjustment of member sizes if necessary. 5. Check on strength of members for worst combination of gravity and horizontal loading, and adjustment of member sizes if necessary. 6. Computer analysis of total structure for more accurate check on member strengths and drift, with further adjustment of sizes where required. This stage may include the second-order P-Delta effects of gravity loading on the member forces and drift.. 7. Detailed design of members and connections.