土木工程道桥方向毕业设计外文翻译原文及译文-日本钢桥建筑的近期发展趋向.doc

外文翻译译文日本钢桥建筑的近期发展趋向摘要： 在本文中，探讨了日本钢桥建筑的最近发展趋向。一提到最近趋向，我们就会发现长和大的钢桥建设实际已经完成了。于是最近主要工作焦点是老化桥梁和现有桥梁的地震改型维护。为了缓和一些老化桥梁对他们周围的环境产生不利的影响对这些桥梁进行恢复和重建是由必要的。为此，维护和改型工作应该是经济合理的工作。国家应该以jsce公布的土木工程师工程规范为基础来改型现有的桥梁，使这些桥梁能够抵御灾害和缓和桥梁对周围环境的不利影响，以此来了解这些工作的必要性和重要性。而且，桥梁工程师应该寻求更好的社会地位，并且桥梁工程学领域应该对将承担未来这个领域的青年学生变得更有吸引力。1.1 建筑趋向在日本，在二十世纪六十年代至八十年代密集的修建了许多桥梁，在经济高速发展时期，每年修建的桥梁数量减少到全部最高数量的一半。更特殊的是，到六十年代下半期，刚桥梁产业到达了黄金时代。尽管rc桥梁和pc桥梁的数量从二十世纪六十年代初到现在几乎保持恒定，然而最新数据表明，最近修建的钢桥数量下降到大约最高量的百分之四十。把许多桥梁的构筑看作重要基础设施之一后，桥梁就主要修建在直接需要的地方。最近，我们观察到六十年代修建的许多桥梁上都发生了各种各样的灾害。尤其是通过对由1995年发生的hyogo-ken nambu地震造成的钢结构的破坏的调查，我们知道新桥的抗震设计和现有钢桥的抗震改型是非常重要的，目的是运用钢桥构件和结构的延展性。许多桥梁修理和结构的地震改型工作由于地震的发生而被破坏，但是这些工作在不久的将来归于完成。钢桥中损坏的部分主要分为桥墩、承力构件和保护桥梁不倒塌的约束构件。最近，长跨度的钢桥地震改型工作已经开始了。例如，在大阪minato桥梁的地震改型工作正在进行，这是一座主跨度为510m的大悬臂行架桥。工程预算为60亿日元，工期为五年。跨径为112m的甲板类型钢板梁桥也在进行着地震改型。现今，许多现有的钢桥存在着许多的破坏形式。例如钢结构的腐蚀，由许多超重荷载造成的 rc平板，钢板和钢结构的断裂，这些荷载远远超出了日本公路桥的规定荷载。结果，许多桥梁需要进行加固、强化和维修工作。改型、强化、维修、维护现有的钢桥已是日本未来钢桥市场中的主要部分，而不再是大跨径桥梁的建设占主要。在日本，从第二次世界大战开始就修建许多桥梁来建立一个高效的高速公路网。然而，注意力主要集中在桥梁在相同设计荷载作用下要近可能的修建安全、标准的桥梁。近来，政府不再考虑桥梁和他们周围环境之间的和谐。例如，由于高层建筑和高架公路桥，要想对大阪城堡的美丽和历史作用有一个清楚和通畅的认识是很困难的。而这就是高架桥对他们周围环境产生不利影响的一个例子。1.2 最近主要的工作（1）新桥建筑在新建工程区段，钢桥产业和混凝土桥产业之间存在着严重的竞争。这是因为占据着钢桥产业的大跨径桥和大桥建筑的数量减少，因而，钢桥产业试图主要在中跨度桥尤其是跨径在40-80m桥建设中赢取市场，结果 ，许多经济、合理和中跨度的新结构桥在钢桥产业和混凝土桥产业中都得到了发展。以下新型钢桥在寻求扩大市场中得到了发展，也包括了那些中跨度的桥：为降低成本使用了少量加强筋和较少焊缝的用厚钢板制成的板梁桥用pc板的双板式梁桥连续、组合和双板式梁桥用悬索来增加经济跨度的连续组合箱梁桥h型钢主梁的悬索静定桥在内部支撑附近存在箱梁的钢桥和在其它部位存在板梁的钢桥另一方面，为了面对钢桥产业面临的竞争，pc桥随之产生的新的类型也得到了发展：波纹钢网的pc箱梁桥有钢构件和pc翼缘的组合行架桥波纹钢网的悬索静定pc箱梁桥（2）钢桥产业的其他发展 （i）下列桥梁构件类型中，用于抵抗疲劳破坏和断裂的维修和加固工作次要钢桥构件的疲劳破坏rc平板的疲劳破坏钢板的疲劳破坏（许多断裂沿着桥面板和弯梁的焊接处开裂）钢桥墩中在柱构件的翼缘板和水平构件的翼缘板之间的焊缝处有许多裂缝现在这些裂缝的维修和加固工作已经开始：（ii）为了增加设计使用荷载的改型工作最大的设计使用荷载从200kn变为了250kn（iii）为了修改设计类型的改型工作例如，在大约40年前，在日本公路桥规范中没有用刚性板的设计方法（iv）地震改型工作（v）依靠生命周期费用和财产管理的桥梁管理系统的发展（vi）对桥梁受力构件和伸缩接缝破坏处的维修和加固工作1.3 维护关于桥梁维护，许多问题可以在桥梁工程学领域解决，尽管也有许多不能单靠桥梁工程来解决的政治和经济问题。下面列出的是有关桥梁维护的争议和问题：（1）生命周期和术语的定义 桥梁维护的定义 在桥梁维护中术语的统一 桥梁构件和其他部位生命周期的决定因素（2） 检查和检测 通过检测桥梁、构件和其他部位来节约因桥梁维护检查而使用的劳力 合理化和低成本的检查方法 对维护工程师进行的教育 通过运用it技术来收集和存储维护数据（3） 评价/评估方法 为评价现有的桥梁的安全性和耐久性以及将结果公布和交流而创建的方法 决定现有桥梁的改型和维修工作优先权的方法的发展（4） 维护系统和维护改型技术 桥梁维护系统的发展，包括维护和改型技术 从维护到设计有效的反馈系统的发展 替换损坏的桥梁结构技术的发展 在维护方面新材料和技术的发展（5） 桥梁与周围环境的和谐 考虑美学中共存和和谐的维护 为用户、居民和自然改善和恢复桥梁周围的环境（6） 维护预算 在预算不足的情况下的维护 财产评估和有效预算1.4 抗震设计和改型各种各样的设计方法和改型方法，为抗震设计和改型使用的技术和材料在hyogo-ken nambu地震后发展。抗震设计程序在hyogo-ken nambu地震后又一下突破：（1） 抗震荷载设计在日本公路桥设计规范中抗震设计类型有两个等级和两种类型第1级：最大弹性反应加速度300加仑第2级类型i：（海洋板材滑动类型）最大弹性反应加速度1000加仑第2级类型ii：（内陆断层滑动类型）最大弹性反应加速度2000加仑（2） 抵抗第1级地震用弹性设计使用的安全系数为1.13（3） 在抵抗第2级地震时弹塑性变形是允许的 根据第1级地震确定的桥梁安全系数在第2级地震中得到证实（4） 抵抗第2级地震的抗震设计方法的两种类型 设计方法a：在这一方法中，地震荷载通过考虑主要结构构件的弹塑性变形而减少 设计方法b：在这一方法中，地震荷载通过引入地震减震器、保险丝装置、关键弹性构件、支撑构件等等而减少1.5 设计工具（1） 分析方法 在日本几乎所有用于弹性线性分析的计算机程序的发展都与桥梁设计有关。对jshb不能够使用调查结果中，对框架结构的弹塑性分析和有限位移分析方法有时得到应用。例如，通过我们实验室和技术科学联合会开发的epass计算机程序。然而，对板式结构的相关分析也已通过使用主要在其他国家发展的计算机系统得到了发展，像abaqus, marc, nastran等等，还有我们的ussp。 对抵抗第2级地震的钢桥墩的动态、弹塑性和有限位移分析也已经开始进行。这一过程使用了日本根据横截面受力（而不是应力）开发的计算机程序。 就组成构件刚性板的扣环连接和组合结构的箱型混凝土的弹塑性性能而论，我们的实验室和技术科学联合会开发了epass/ussp计算机系统，这是一种为解决包括薄壁钢和组合结构空间桥的多功能静态/动态弹塑性和有限位移的方法。（2）实验方法在hyogo-ken nambu地震后，假设动态测试在日本变得非常普遍。京都大学和大阪学院业开发了一个多元的假设动态测试系统，可以模仿一个多元结构的动态特性，这使得许多不同的实验室通过互联网进行合作。1.6新材料和技术桥梁的新的高性能材料不断得到了发展，例如包括高性能钢、高性能支座、高延展和高强度螺栓，碳纤维加筋塑性板材、碳纤维加筋塑性悬索等。在他们之中，碳纤维加筋塑性板材和rc板可用于老化桥梁的维修和圆横断面钢桥墩的地震改型。然而，确认这些高性能材料适当的被应用于结构似乎是非常困难的。另一方面，各种各样用于地震设计、地震改型、降低成本、振动控制的高性能技术正在开发中。considerations on recent trends in, steel bridge construction in japanabstract in this paper, consideration is given on recent trends in, steel bridge construction in japan. as far as recent trends are concerned, it is observed that the construction of long and big steel bridges has practically been completed. consequently, the focus of recent main works is the maintenance of superannuated (averaged) bridges and the seismic retrofitting of existing bridges. the refreshment and regeneration of some superannuated bridges is also needed recently in order to mitigate the uncomfortable influence of these bridges on their surrounding environment. for this purpose, maintenance and retrofitting works should be economically reasonable jobs. the necessity and importance of these works should be understood by the nation through retrofitting existing bridges against disasters and mitigating the unfavorable influence of bridge structures on the bridge environment on the basis of the code of ethics for civil engineers promulgated by jsce. moreover, bridge engineers should seek better social status and the bridge engineering field should become attractive to young students who will bear the future of this field. 1.1 construction trendin japan, many bridges were intensively constructed in the 1960s80s, during the period of high economic growth, with the number of bridges constructed per year decreasing recently to half of the overall peak. more specifically, the steel bridge industry reached the golden age in the latter half of the 1960s. however, the latest data indicates that the recent number of constructed steel bridges has declined to approximately 40% of its peak, though the number of constructed rc and pc bridges remains almost constant from the beginning of 1960 to date. after the construction of many bridges as one of the important infrastructures, bridges were constructed predominantly in places of direct need. recently, it is observed that various kinds of damage have occurred to many bridges mainly constructed in the 1960s. especially following the investigation of damage to steel structures due to the hyogo-ken nambu earthquake which occurred in 1995, importance has been attached to seismic design for the construction of new bridges and to seismic retrofitting for existing steel bridges, aiming to utilize the ductility of steel bridge members and structures. many repair and seismic retrofitting works of bridge structures damaged as a result of the earthquake have been carried out and these works are due to finish in the near future. damaged parts in steel bridges were mainly classified into piers, bearings and restraining parts protecting bridges from falling down. recently, the seismic retrofitting works of long-span steel bridges has started. for example, the seismic retrofitting work of the minato bridge in osaka, a big cantilever truss bridge with a main span of 510 m is now under way, with an estimated budget of 6000 million japanese yen and a works duration of 5 years. the maitani bridge located in nara prefecture, a deck-type steel girder bridge with the span length of 112 m is also undergoing seismic retrofitting. nowadays, many existing steel bridges exhibit some form of deterioration, such as the corrosion of steel members, fatigue cracks in rc slabs, steel decks and steel members due to the passage of many overweight vehicles, much heavier than those specified in the japanese specifications for highway bridges (jshb), and so on. as a result, many bridges require substantial strengthening and repair works. instead of the construction of large and long-span bridges, the retrofitting, strengthening, repair and maintenance of existing steel bridges already constructed will take an increasingly important part of the future steel bridge market in japan. in japan, many bridges have been constructed to establish an efficient highway network since world war ii. attention has been, however, paid mainly to the construction of safe and standard bridges with, as far as possible, uniform quality with regard to design loads. until recently, governments could not afford to consider the harmony between the bridges and their surrounding environment. for example, it is very difficult to have a clear and unobstructed view of the beautiful and historically important osaka castle due to the high-rise buildings and elevated highway bridges. this is an example of the undesirable influence of elevated bridges on their surrounding environment. 1.2. recent main works（1）construction of new bridges in the new construction sector, there is severe competition between the steel bridge and concrete bridge industries. this is because the construction of long-span and big bridges, which occupied the steel bridge industry, has declined and, consequently, the steel bridge industry tries to win jobs mainly in the construction of mid-span bridges, typically with a span length of 4080 m. as a result, many economical, rational and mid-span bridges with new types of structures have been developed by both steel and concrete bridge industries. the following new types of steel bridges were developed in seeking to expand the market for new construction, to include bridges with medium span length: plate girder bridges made of thick steel plates, with fewer stiffeners and less welding lines for cost reduction. two-main-plate girder bridges with pc decks. continuous, composite and two-main-plate girder bridges. continuous composite box-girder bridges strengthened by cables to increase their economical span length. cable stayed bridges with main girders of h-shaped steels. steel bridges consisting of box girders in the vicinity of the interior supports and plate girders in the other parts.on the other hand, the following new types of pc bridges have also been developed in order to face the competition from the steel bridge industry: pc box girder bridges with corrugated steel webs. compound truss bridges with steel diagonal members and pc flanges. cable stayed pc box girder bridges with corrugated steel webs.（2） other developments in steel bridge industry （i）repair and strengthening works against fatigue damage and cracks in the following types of bridge members: fatigue cracks of secondary steel bridge members. fatigue cracks of rc slabs. fatigue cracks of steel decks (some cracks along welding parts between deck plates and trough ribs). many cracks at ends of welding parts between the flange plates of column members and the lower flange plates of horizontal members in steel bridge piers.repair and strengthening works of these cracks are carried out now. （ii）retrofitting works against increased design live load. maximum design live load was changed from 200kn to 250kn.（iii）retrofitting works due to revised design specifications. for example, there was no design method for stiffened plates in jshb about 40 years ago.(iv) seismic retrofitting works.(v) development of bridge management systems based on life cycle cost (lcc) and asset management.（vi）repair and strengthening works of damage to bridge bearings and expansion joints.（vii）maintenance works on permeable pavements.1.3. maintenanceregarding the maintenance of bridges, there are many issues that can be solved by the bridge engineering community, though there are also many political and economical problems which cannot be solved by the bridge engineering community alone. issues and problems of bridge maintenance are listed below: （1）definition of terminology and life cycle. definition of bridge maintenance. unification of the terminology on bridge maintenance. decision of the life cycle of bridges, members and their parts.（2） inspection and monitoring. labor saving of inspection for maintenance through monitoring bridges, members and their parts. rationalization and cost reduction of inspection methods. education for maintenance engineers. collection and storage of maintenance data by utilizing it technology.（3） evaluation/assessment methods. establishment of methods for evaluating the safety and durability of existing bridges and the public announcement and communication of evaluated results. development of method for deciding the priority ranking of repair and retrofitting of existing bridges.（4）maintenance system, and repair and retrofitting technique. development of bridge maintenance system including repair and retrofitting technique. development of effective feedback system from maintenance to design. development of techniques for replacing deteriorated bridge structures. development of new materials and techniques for maintenance. （5） harmony between bridges and their surrounding environment. maintenance considering the co-existence and harmony of aesthetics, improvement and refreshment of environment surrounding bridges for users, inhabitants, and nature.（6）budget for maintenance. maintenance in case of insufficient budget. asset assessment and effective budget.1.4. seismic design and retrofitting various design methods, retrofitting methods, technologies and materials for seismic design and retrofitting have been developed after the hyogo-ken nambu earthquake. the seismic design procedures after the hyogo-ken nambu earthquake are highlighted below: （1） design seismic loads.there are two levels and two types of design earthquake specified in jshb. level 1: maximum elastic response acceleration 300 gal. level 2 type i (ocean plate slip type): maximum elastic response acceleration 1000 gal. level 2 type ii (inland fault slip type): maximum elastic response acceleration 2000 gal.（2） elastic design is carried out against the level 1 earthquake with the safety factor of 1.13.（3）elasto-plastic deformation is allowed against level 2 earthquakes. the safety of a bridge dimensioned on the basis of a level 1 earthquake is verified by using a level 2 earthquake.（4）two types of seismic design methods against level 2 earthquakes; design method a in which the seismic load is reduced by taking into account the elasto-plastic deformation of main structural members. design method b in which the seismic load is reduced by introducing seismic dampers, fuse members, key plastic members, bracing members, and so on.1.5. design tools（1）analytical methods the computer programs developed in japan are principally used for almost all the elastic linear analyses associated with bridge design. in investigating issues to which jshb can not be applied, the elasto-plastic and finite displacement analyses for framed structures are sometimes carried out, for example, by the computer program epass developed by our laboratory and jip techno science corporation. however, corresponding analyses for plated structures are carried out using computer programs developed mainly in other countries, such as abaqus, marc, nastran etc. and sometimes our own ussp. dynamic, elasto-plastic and finite displacement analyses for steel bridge piers subjected to the level 2 earthquakes are carried out by using computer programs using the yield criterion developed in japan in terms of cross sectional forces (rather than stresses). our laboratory and ji