Bridge landscape is a new subject field. Due to the "fat" structure and "thin" landscape phenomenon in bridge engineering design industry, the research on bridge landscape design in China is relatively silent. Therefore, to understand the significance and characteristics of bridge landscape, the significance of bridge landscape bears the brunt.

This paper is an exchange paper of the 5th National Symposium on Road and Bridge Technology, which was published in New Progress of Modern Road and Bridge Technology.

1. Interpretation of Bridge Landscape

The word landscape was originally a typological concept of natural geographical features. At the beginning of last century, German geographer O. Schluter1872-1952 understood the landscape from the perspective of the comprehensive representation of natural and human phenomena, and discussed the process from the original landscape to the human landscape. The intervention of humanistic factors makes landscape science advance by leaps and bounds, and also makes people realize that since human activities can bring changes in landscape appearance, if this change is controlled and guided according to certain laws, the landscape will develop in the direction that conforms to people's wishes, which promotes the concept of landscape design. But the landscape of the earth is complex, and all kinds of landscapes have different composition rules. Therefore, in some landscape construction fields that are mature or have high technical characteristics in the development of human history, such as cities, buildings, bridges, roads, dams and other industries, people still follow their habits and dare not rashly call them landscape design. But this can't change the nature of these different types of human landscapes.

It has always been the behavior of architects who know the laws of bridge structure to organize and optimize the bridge shape according to aesthetic laws. In the second half of the last century, people began to realize that bridge design should not only "care about themselves" but also "care about others", such as caring about the influence of bridges on cities and the earth and caring about the symbolic significance of bridges. Landscape ecology raises bridges to the height of solving the survival and reproduction of species in the land cut by roads, that is, bridges should also "care" about the ecological environment. None of these problems can be covered by bridge aesthetics, and its comprehensive solution requires professionals who understand both the laws of bridge aesthetics and the scientific construction of landscape. This is the foundation of the birth of bridge landscape! Frederick Gottemoeller, an American scholar, synthesized Bridgescape landscape into a new word to express this new combination in 1990s.

However, people pay more attention to the landscape problems in bridge construction. The total length of the Honshu-Shikoku Bridge project in Japan is 178km, and it is the first time in human history to build such a super-large-scale bridge. People can't help but think about the damage and interference of bridge construction to the natural environment, and hope that the new bridge will become a new landscape with the characteristics of the times while caring for the history, culture and nature reserves it passes through. This makes the Japanese government aim at giving full play to the ornamental and cultural functions of the bridge, linking the environmental protection around the bridge site with the development and utilization, and "pursuing world-class landscape". Similar practical activities not only provide a practical platform for bridge landscape design, but also lay a scientific foundation for bridge landscape discipline.

The understanding of bridge landscape in China is generally reflected in the decomposition of the word "landscape", that is, "viewing" the bridge and viewing "landscape" on the bridge, and the combination of the two is "landscape". This concept has its historical tradition. Classical garden bridges have long had this unique consideration in terms of "scenery" and "view", and China's landscape architecture knows this well. We say that the relationship between "scenery" and "view" truly reflects the spatial relationship among people, bridges and environment, and its implication is quite characteristic of China, which is the crystallization of our cultural wisdom! However, only by combining this concept with the construction theory of landscape science can it have more positive significance in respecting and transforming nature.

2. The significance of bridge landscape research

2. 1 Promote the deepening and institutionalization of landscape design in bridge construction

In the past 20 years since the reform and opening up, 224,000 highway bridges have been built in China, but the landscape design of bridges still stays at the level of taking the formal beauty of bridges as the leading principle, and developed in the 1950s and 1960s. This can not adapt to the higher requirements of the motherland for environmental quality with great strides in material civilization. Specific performance in the following four aspects:

First, as early as 1994, the state decided on the strategy of one-vote environmental protection veto system for major projects, but the bridge landscape design did not respond to this.

Second: Bridge landscape is always accompanied by landscape and urban landscape, and sometimes its composite landscape is more significant. For example, the landscape of Sydney Bridge and Sydney Opera House has become the symbol of Sydney and even Australia. Wuhan Yangtze River Bridge has always been the pride of Wuhan. The tradition of attaching importance to ontology landscape makes us ignore the accompanying landscape.

Thirdly, the strategic position of the bridge in the urban pattern makes its night landscape an important part of urban lighting. In the waterfront where the bridge is located, its broad vision is the focus of urban landscape expression, and the night landscape of the bridge plays an important role in expressing the depth of field and spatial level of urban night landscape. This is intolerable for traditional bridge landscape design.

Fourthly, the phenomenon of "fat" structure and "thin" landscape in the field of bridge design not only makes the research of bridge landscape design silent, but also fails to combine some new methods of related disciplines.

Fifth, due to the rapid development of bridge structure technology, new bridge types are constantly emerging, which continuously injects fresh blood into bridge landscape science and creates a new stage for landscape design. It has become an important aspect of bridge landscape research to explore the landscape expression of new bridge type and combine it with regional characteristics.

These are all aspects that need to be deepened in bridge landscape research, and they are also the driving force for the institutionalization of bridge landscape design.

2.2 Meet the higher requirements of society for bridge landscape.

Bridge landscape design can't keep up with the requirements of society, because:

The large-scale construction of a bridge not only means consuming huge social funds, but also reflects the requirements of frequent interaction of social materials for spatial leap. Bridges have become a landscape all over urban and rural areas. As a phenomenon, their landscape characteristics are linked with material civilization, which makes the bridge landscape have the characteristics of material civilization.

Second, the bridge landscape has become the pride of urban residents because of its huge volume and unique shape. It not only includes the progress and development of society, but also expresses a kind of praise to social system and human strength. In addition, the bridge landscape also has the meaning of geographical communication, that is, the so-called "link" strategic significance, which makes the bridge landscape often become the focus of urban culture and the window of urban image. It also makes the bridge landscape have the significance of spiritual civilization.

In addition to its smooth modeling, concise modeling and large-space jumping, the bridge landscape also has great material landscape shock. Historical events, the intervention of historical figures or the realization of human self-worth all show the charm of cultural landscape.

The above points make local governments or investors more interested in the construction of bridge landscape, which is also the reason for advanced social consciousness. This is the pressure of bridge landscape design and research, and also the driving force of bridge landscape development!

2.3 shaping a distinctive urban landscape significance

Many towns in China are famous for their bridges. Most cities almost have names of places, blocks or administrative divisions related to bridges. There are both historical precipitation and modern bridge landscape. This is the symbolic function of bridge landscape to the city. Whether it is a water bridge on rivers, lakes and seas, or a dry bridge on an urban interchange or expressway, it is generally the key to the structure of a city or a region, which makes bridges have an unshirkable responsibility for shaping the image of a city or a region.

The bridge types of Chinese bridges have strong characteristics of the times. Such as wooden bridges in 1950s, arch bridges in 1960s and 1970s, beam bridges in 1980s, cable-stayed bridges in 1990s, suspension bridges and overpasses at the end of 20th century. The bridge climax of each era is the result of the rapid development of its structural technology. The scientific and technological characteristics of bridge structural technology and the continuous renewal of structural technology make the bridge landscape have a profound brand of the times. Because of the strategic position of the bridge in the city, its characteristics of the times will infect the city, resulting in a comprehensive and overwhelming effect.

The geography, landform or urban space environment where the bridge crosses has its particularity. The cooperation with the surrounding space environment makes the bridge landscape organically dissolved in the environment, and also makes the familiar environmental space and the bridge landscape with development significance accompanied by local landscape. The combination of bridge and city makes its composite landscape become a symbol of the uniqueness and uniqueness of the city, and it is also a reflection of the regionality of bridge landscape.

2.4 Provide reasonable decision-making reference for bridge construction from the perspective of landscape.

There is no corresponding technical specification for bridge landscape design in China, which makes the thinking of bridge landscape lack of scientific basis. In the feasibility study of bridge design scheme, landscape is only the packaging behind the structure or the aesthetic adjustment of the structural relationship. The study of bridge landscape not only tries to reveal more new trends of bridge landscape development, but also comprehensively considers politics, economy, technology and environmental protection, so as to sort out the principles of landscape design and deepen decision-making or planning.

3. The characteristics of bridge landscape

3. 1 Technical aesthetic characteristics of bridge landscape

Bridges cannot be landscaped for absolute beauty. The first is to solve the traffic function and optimize between technical possibility and economy. This is the basic requirement of bridge design code. Therefore, bridge landscape design must meet the requirements of bridge function, technology and economy, and take this as the principle to adjust the landscape elements aesthetically. Such as the aesthetic comparison and selection of bridge types, the proportion adjustment of bridge structural members, the coordination between bridge route selection and urban or terrestrial landscape scale, and the connection between bridge protective painting and urban overall color. The technical aesthetic feature of bridge landscape is that it pays attention to function and technology. However, when the landscape value advantage is obvious, the function is satisfied and the technology is feasible, sometimes the economic factors can lag behind. Such as bridges in scenic spots or bridges in important urban structures. Therefore, some related fields of bridge landscape design will have different rankings under different environmental conditions.

3.2 bridge landscape in the era

As mentioned above, the types of bridges in China have strong characteristics of the times. An important significance of the times is "new", such as new things, new developments, new phenomena, new landscapes, new knowledge, new cultures and new technologies, which can express the significance of the times. The scientific and technological characteristics of bridge structural technology and the continuous renewal of structural technology are the leading factors that make the bridge landscape have a profound brand of the times. Because of the strategic position of bridge in the city, bridge landscape has become the focus of urban visual recognition, extending the expression of bridge landscape to the city. Therefore, it is a problem that we need to pay attention to in the design of bridge landscape to grasp this characteristic of bridge landscape and display it properly in the city.

3.3 the regionality of bridge landscape

The spatial crossing of the bridge makes the traffic three-dimensional, and the geography, landform or urban spatial environment of the bridge crossing has its particularity. The coordination between the bridge and the topography of a specific place has become an important aspect to be considered in the bridge landscape design. The coordination with the surrounding space environment makes the bridge landscape organically dissolved in the environment, and also makes the well-known environmental space and the bridge landscape with development significance have local landscape renewal significance. Inheritance and development in landscape renewal are the deep-seated reasons for its symbolic role. The combination of bridge and city makes its composite landscape become a symbol flaunting the uniqueness and uniqueness of the city, such as Yan 'an Bridge and Baota shan, Brooklyn Bridge and Manhattan, which is also a reflection of the regionality of bridge landscape.

[References]

1. Tang Huancheng's Philosophy of Bridge Beauty Railway Press 2000

2. Christine Bridge Aesthetics People's Communications Press 1987

3. Frederick Gottemoeller, Bridge Landscape: The Art of Designing Bridges. Son company 1998.

4. Henry Petroschi, Dream Engineer: Great Bridge Builder and American Leap, American Antique Books, 1996.