第3个回答 2014-04-23
对土木工程的发展起关键作用的,首先是作为工程物质基础的土木建筑材料,其次是随之发展起来的设计理论和施工技术。每当出现新的优良的建筑材料时,土木工程就 会有飞跃式的发展。
人们在早期只能依靠泥土、木料及其它天然材料从事营造活动,后来出现了砖和瓦这种人工建筑材料,使人类第一次冲破了天然建筑材料的束缚。中国在公元前十一世纪 的西周初期制造出瓦。最早的砖出现在公元前五世纪至公元前三世纪战国时的墓室中。砖和瓦具有比土更优越的力学性能,可以就地取材,而又易于加工制作。
砖和瓦的出现使人们开始广泛地、大量地修建房屋和城防工程等。由此土木工程技术得到了飞速的发展。直至18~19世纪,在长达两千多年时间里,砖和瓦一直是土木工程的重要建筑材料,为人类文明作出了伟大的贡献,甚至在目前还被广泛采用。
钢材的大量应用是土木工程的第二次飞跃。 十七世纪70年代开始使用生铁、十九世纪初开始使用熟铁建造桥梁和房屋,这是钢结构出现的前奏。
从十九世纪中叶开始,冶金业冶炼并轧制出抗拉和抗压强度都很高、延性好、质量均匀的建筑钢材,随后又生产出高强度钢丝、钢索 。于是适应发展需要的钢结构得到蓬勃发展。除应用原有的粱、拱结构外,新兴的桁架、框架、网架结构、悬索结构逐渐推广,出现了结构形式百花争艳的局面。
建筑物跨径从砖结构、石结构、木结构的几米、几十米发展到钢结构的百米、几百米,直到现代的千米以上。于是在大江、海峡上架起大桥,在地面上建造起摩天大楼和高耸铁塔,甚至在地面下铺设铁路,创造出前所未有的奇迹。
为适应钢结构工程发展的需要,在牛顿力学的基础上,材料力学、结构力学、工程结构设计理论等就应运而生。施工机械、施工技术和施工组织设计的理论也随之发展,土木工程从经验上升成为科学,在工程实践和基础理论方面都面貌一新,从而促成了土木工程更迅速的发展。
十九世纪20年代,波特兰水泥制成后,混凝土问世了。混凝土骨料可以就地取材,混凝土构件易于成型,但混凝土的抗拉强度很小,用途受到限制。 十九世纪中叶以后,钢铁产量激增,随之出现了钢筋混凝土这种新型的复合建筑材料,其中钢筋承担拉力,混凝土承担压力,发挥了各自的优点。 二十世纪初以来,钢筋混凝土广泛应用于土木工程的各个领域。
从三十年代开始,出现了预应力混凝土。预应力混凝土结构的抗裂性能、刚度和承载能力,大大高于钢筋混凝土结构,因而用途更为广阔。土木工程进入了钢筋混凝土和预应力混凝土占统治地位的历史时期。混凝土的出现给建筑物带来了新的经济、美观的工程结构形式,使土木工程产生了新的施工技术和工程结构设计理论。这是土木工程的又一次飞跃发展。
建造一项工程设施一般要经过勘察、设计和施工三个阶段,需要运用工程地质勘察、水文地质勘察、工程测量、土力学、工程力学、工程设计、建筑材料、建筑设备、工程机械、建筑经济等学科和施工技术、施工组织等领域的知识 ,以及电子计算机和力学测试等技术。因而土木工程是一门范围广阔的综合性学科。随着科学技术的进步和工程实践的发展,土木工程这个学科也已发展成为内涵广泛、门类众多、结构复杂的综合体系。
土木工程是伴随着人类社会的发展而发展起来的。它所建造的工程设施反映出各个历史时期社会经济、文化、科学、技术发展的面貌,因而土木工程也就成为社会历史发展的见证之一。
远古时代,人们就开始修筑简陋的房舍、道路、桥梁和沟澶,以满足简单的生活和生产需要。后来,人们为了适应战争、生产和生活以及宗教传播的需要,兴建了城池、运河、宫殿、寺庙以及其他各种建筑物。
许多著名的工程设施显示出人类在这个历史时期的创造力。例如,中国的长城、都江堰、大运河、赵州桥、应县木塔,埃及的金字塔,希腊的巴台农神庙,罗马的给水工程、科洛西姆圆形竞技场(罗马大斗兽场),以及其他许多著名的教堂、宫殿等。
产业革命以后,特别是到了20世纪,一方面社会向土木工程提出了新的需求;另一方面,社会各个领域为土木工程的前进创造了良好的条件。因而这个时期的土木工程得到突飞猛进的发展。在世界各地出现了现代化规模宏大的工业厂房、摩天大厦,核电站、高速公路和铁路、大跨桥梁、大直径运输管道长隧道、大运河、大堤坝、大飞机场、大海港以及海洋工程等等。现代土木工程不断地为人类社会创造崭新的物质环境,成为人类社会现代文明的重要组成部分。
土木工程是具有很强的实践性的学科。在早期,土木工程是通过工程实践,总结成功的经验,尤其是吸取失败的教训发展起来的。从17世纪开始,以伽利略和牛顿为先导的近代力学同土木工程实践结合起来,逐渐形成材料力学、结构力学、流体力学、岩体力学,作为土木工程的基础理论的学科。这样土木工程才逐渐从经验发展成为科学。
在土木工程的发展过程中,工程实践经验常先行于理论,工程事故常显示出未能预见的新因素,触发新理论的研究和发展。至今不少工程问题的处理,在很大程度上仍然依靠实践经验。
土木工程技术的发展之所以主要凭借工程实践而不是凭借科学试验和理论研究,有两个原因:一是有些客观情况过于复杂,难以如实地进行室内实验或现场测试和理论分析。例如,地基基础、隧道及地下工程的受力和变形的状态及其随时间的变化,至今还需要参考工程经验进行分析判断。二是只有进行新的工程实践,才能揭示新的问题。例如,建造了高层建筑、高耸塔桅和大跨桥梁等,工程的抗风和抗震问题突出了,才能发展出这方面的新理论和技术。
在土木工程的长期实践中,人们不仅对房屋建筑艺术给予很大注意,取得了卓越的成就;而且对其他工程设施,也通过选用不同的建筑材料,例如采用石料、钢材和钢筋混凝土,配合自然环境建造了许多在艺术上十分优美、功能上又十分良好的工程。古代中国的万里长城,现代世界上的许多电视塔和斜张桥,都是这方面的例子。
Plays a key role in the development of civil engineering, is the first civil construction materials as the basis for engineering material, followed by the subsequent development of the design theory and construction technology. Whenever there is a fine new building materials, civil engineering will be a leap type development.
People can only rely on the early Earth, wood and other natural materials in the construction activities, and later appeared in brick and tile that artificial materials, so that the first human to break the shackles of natural building materials. Chinese in Eleventh Century BC in the early Western Zhou Dynasty created the tile. The first brick in the fifth Century BC to the third Century BC, the tomb of the Warring States period. Brick and tile has superior mechanical properties,soil can obtain raw material locally, and easy to manufacture.
Emergence of brick and tile so that people began to widely, a large number of housing construction and urban flood control engineering. This civil engineering technology has been rapid development. Until 18 ~ nineteenth Century, as long as two thousand years, brick and tile has been a major civil engineering construction materials, made a great contribution to the human civilization, and was also widely used in the present.
A large number of applications of steel products is the second leap in civil engineering. In seventeenth Century 70 time began using pig iron, the early nineteenth Century began to usewrought iron bridges and the construction of housing, which is a prelude to the emergence of steel.
From the beginning of the mid nineteenth Century, the metallurgical industry smelting and rolling out high tensile and compressive strength, good ductility, uniformity of the quality of construction steel, then produce high-strength steel wire, steel wire. And meet the needs for development of steel structure has been booming. In addition to the application of the original beam, arch structure, the new truss, frame, grid structure, and gradually promote the suspension structure,the form of the structure of a hundred flowers contend in beauty situation.
From the brick building long-span structure, stone structure, wood structure of a few meters, the development of tens of meters to 100 meters of steel structures, several hundred meters, 1000 meters until modern. So the bridge in the river, channel, since the construction of skyscrapersand high-rise tower on the ground, even in the laying of underground railway, to create ahitherto unknown.
To meet the development needs of the steel structure engineering, on the basis of Newton's mechanics, material mechanics, structural mechanics, structural engineering design theory would emerge as the times require. Theoretical design of machinery, construction technology and organization construction also development, civil engineering from the experience of rising to become science, both in engineering practice and theoretical basis for a new, which led tomore rapid development of civil engineering.
In nineteenth Century 20, Portland cement concrete was made. Concrete aggregate can obtain raw material locally, easy to concrete structures forming, but the tensile strength of concrete is very small, limited use. By the middle of the nineteenth Century, the surge in steel production,followed by a composite building material of this new type of reinforced concrete, which bear the tension steel, concrete bear the pressure, to play their respective advantages. Since the beginning of twentieth Century, each field of reinforced concrete is widely used in civilengineering.
From the beginning of the thirty's, the prestressed concrete. The crack resistance, stiffness and bearing capacity of prestressed concrete structure, much higher than the reinforced concrete structure, which uses broader. Civil engineering into the reinforced concrete and prestressed concrete dominant historical period. Concrete brings the structural form of new economic,aesthetic to the building, civil engineering so that a theory of new construction technology and engineering structure design. This is a leap in the development of civil engineering.
A project to build the facilities in general to go through investigation, design and construction in three stages, need to discipline the use of geological prospecting projects, hydro geological survey, engineering survey, soil mechanics, engineering mechanics, engineering design,building materials, construction equipment, engineering machinery, building the economy, and the construction technology, construction and other fields of knowledge, as well as the computer and mechanical testing technology. Civil engineering is therefore a broad range of integrated disciplines. With the development of science and technology development and engineering practice, the civil engineering disciplines have also been developed into a comprehensivesystem of broad connotation, category numerous, complicated structure.
Civil engineering is accompanied by the development of human society and the development of.It works in the construction of facilities reflect the face of social and economic development,technology, science, culture in every historical period, so the civil engineering has become one of the social and historical development of the witness.
In ancient times, people began to build simple houses, roads, bridges and water channel, to meet the simple life and production needs. Later, people in order to adapt to the war, productionand dissemination of religious life and the need to build the city, canals,, palaces, temples and other buildings.
Many well-known works shown in this historical period of human creativity. For example, Chinathe Great Wall, Dujiangyan, the Grande Canale, the Zhaozhou Bridge, the Yingxian Wood Tower, the Pyramid of Egypt, Greece's Parthenon, Rome's water supply project, Kolo Sim Arena(Rome Coliseum), and many other famous churches, palaces.
After the industrial revolution, especially in twentieth Century, on one hand, the society puts forward new requirements to the civil engineering; on the other hand, each field of the society to create good conditions for the advancement of civil engineering. Thus this period of civil engineering has make a spurt of progress of development.
In the rest of the world in the modern large-scale industrial plants, skyscrapers, nuclear power plants, highways and railways, long-span bridge, large diameter pipelines long tunnel, the Grande Canale, big dams, big airport, port and marine engineering etc.. Modern civil engineering to create a new physical environment for the human society, has become an important part of modern civilization of human society.
Civil engineering is a very practical subject. In the early days, through the civil engineering practice, summing up successful experience, especially draw lessons from the failure of developed. From the beginning of seventeenth Century, with Galileo and Newton as a combination of pilot with the mechanics of the modern civil engineering practice, gradually formed the mechanical material mechanics, structural mechanics, fluid mechanics, rock mass, as the basis of the theory of civil engineering discipline. This experience in civil engineering from the gradually developed into a science.
In the process of the development of civil engineering, engineering practice often first experience in theory, engineering accidents often show a new unforeseen factors, triggering a new theory of research and development. Yet many engineering problems, still rely on practical experience in the very great degree.