RETRACTED ARTICLE: Mountain bridge design based on remote sensing images

Abstract

The bridge identification method in the high-resolution remote sensing image is realized by using the characteristics of the bridge. Now, due to the continuous leap forward in sensing technology, the data volume of remote sensing images has increased substantially, and the resolution of remote sensing images has also been continuously improved. People are paying more and more attention to the automatic recognition and positioning of bridges in remote sensing images. Automatic bridge recognition technology can automatically extract bridge signs from the complex background of earth observation images through high-speed real-time information processing based on specific regions and various input function template databases and detect, intercept, identify, and track targets. By using the characteristics of typical targets or image edges, grayscale, texture structure meaning, and regional shape, satellite remote sensing images have the advantage of being able to provide surface information at a high speed. However, in special cases such as low resolution (medium and low), the acquisition and measurement of GIS information cannot play a good role. In order to provide a reliable guarantee for mapping and map updates, it is necessary to develop high-resolution satellite remote sensing images. Use remote sensing images with high spatial resolution as the data source, and use a rule-based object-oriented method to correctly extract bridge targets from high-resolution images. First, through multi-scale scoring experiments, combined with the characteristics of the bridge, select the best segmentation ratio. Second, the rule set is established using the water index and threshold function method, and the vector files of the water area and the bridge are gradually obtained. Finally, the bridge target can be obtained normally through binarization, mathematical shape processing, overlay analysis, and other methods.

Introduction

Starting from the fundamental meaning of bridge modeling design, it summarizes and refines the views of many famous world-class bridge engineers and artists and combines the modern era to expand bridge aesthetics to the field of art. On this basis, starting with the coordination of the bridge structure at the level of the environment and its various parts, based on the environmental coordination and functional adaptability, respectively, the paper puts forward the principles and methods with strong operability for the selection of bridge structure type and the design of various components (McClymont and Smith 1996). Whether the shape is coordinated is the key to the success or failure of a bridge’s modeling quality (Mailapalli et al. 2008). The most beautiful bridges in the world are recognized as coordinated. However, coordination is a perceptual level concept, and how to achieve the coordination of bridge modeling involves many disciplines. Innovatively combine the research results of bridge engineering and architecture to form the “Skyline Rule” to guide the selection of bridge types (Mailhol et al. 1997). In terms of environmental coordination, four types of beam bridges, arch bridges, cable-stayed bridges, and suspension bridges are explained (Merriam 1977). The shape and top shape characteristics of the main bridge types, as well as the characteristics of some typical environments, are compared and matched with a large number of examples to illustrate the adaptation of the main bridge types under different environmental conditions (Merriam and Keller 1978). In addition, it draws on the classic Bauhaus thought system in modern art design, combines its original purpose such as “form follows function” with the component design of the bridge, and further illustrates it through the application of examples at the end (Nie et al. 2012). Finally, using the methods and guiding principles proposed in the previous chapters, the landscape and modeling effects of the Chongqing Cuntan Yangtze River Bridge were discussed. The conclusion is that the Cuntan Yangtze River Bridge performs better in coordination with the environment, but the proportions of the bridge towers are not (Kreyszig 1979). The coordination and decoration use is unreasonable, so it needs to be improved. In addition, using the Bauhaus ideological system, starting from the two aspects of environmental coordination and functionality, the proposed Chongqing Huangjueping Yangtze River Bridge was designed and achieved better results, which further confirmed the feasibility and practicability of the new method and guiding principle (Philip 1957). From advocating complex decorative sculptures in the past to pursuing simple and concise lines, people’s aesthetic concepts for bridges have shown constant changes (Scaloppi et al. 1995). However, the excellent bridge masterpieces from ancient times to the present are models of coordinated modeling, so no matter what the future where will the aesthetic orientation lead the design of the bridge shape? Coordination is the eternal theme (Serralheiro 1995).

Materials and methods

Data source and preprocessing

As shown in Table 1, the preprocessing of GF-1 data is completed on the ENVI5.1 platform, including image cutting, geometric correction, radiation calibration, and image fusion. GF-1 uses remote sensing images, RPC files, DEM data, and orthographic correction to improve the extraction accuracy and uses triple convolution interpolation to smooth the image when resampling. Next, consider the characteristics of the GF-1 remote sensing image with a large area and wide map, crop a specific survey area based on the ArcGIS 10.0 platform, perform radiometric calibration, reset the gain offset parameter acquisition, and then complete the FLAASH atmosphere calibration (Seyedzadeh et al. 2020a). In the subsequent image fusion, the radiation resolution of the GF-1 remote sensing image is also high. Considering the simultaneous existence of punk data (2m) and multispectral data (8m), through the fusion of the two, the fusion image can protect the multispectral image. Not only the spectral characteristics are preserved, but the spatial details of the picture are also preserved. It can strengthen the target function and improve the ability of image interpretation (Seyedzadeh et al. 2020b).

Table 1 GF-1 satellite payload PMS parameters

Calculation method of mountain flood flow

Considering that the watershed area is the most important factor affecting the peak flow, the difference in watershed area will be based on the watershed area and peak value when the measured flow data and a specific number of storm flood data exist for a long time. Peak flow was calculated based on the frequency of the empirical formula between flows:

$$ {Q}_N={K}_N{F}^n $$

(1)

In formula (1), Q_N is the design peak flow rate with a return period of N (m^3/s); F is the design watershed area (km^2); K_N,n is the empirical formula parameters of the return period (see Table 2).

Table 2 Empirical formula calculation parameter table

Starting from Table 2, within the same hydrological area, the hydrological basin of the watershed does not exceed 20% of the area. In the basin below 1000km², storms and floods are evenly distributed, and water supplement is used as a similar area for water collection on the platform. The design flood flow is calculated based on the measured flood data. Secondly, the design watershed is estimated based on the analogy of the watershed area:

$$ {Q}_x={\left(\frac{F_x}{F_0}\right)}^n\ast {Q}_0 $$

(2)

In formula (2), n is the experience index, generally 0.5~0.8 according to regional experience value; Q_x and F_x are the flood flow (m^3/s) and catchment area (km^2) of the designed basin; Q₀ and F₀ are the flood flow (m^3/s) and catchment area (km^2) of the participating station.

It can be seen from formula (2) that this formula is applicable to the design flood flow of bridges whose catchment area exceeds 1000km² and the catchment area is lower than 20% of the catchment area of ​​the same hydrological observation station. Because the integrated water area of the design part and the reference station differs by more than 3%, the reliability of the calculation result of this formula is reduced. In this formula, the rainstorm must be evenly dispersed (Singh and Ram 1983). This formula is not applicable when the storms are not evenly distributed.

Comprehensive parameter method

Flood flow is not only affected by the area of the basin, but also by the shape of the basin, the inclination of the river course, and the intensity of the storm. In fact, the all-inclusive parameter method is a multi-factor experimental formula for calculating the design flood flow, and it is a comprehensive experimental formula that takes into account various watershed characteristic parameters in the watershed. Based on the natural and geographical conditions where the flood occurred, the Hydrological Comprehensive Bureau of a certain area established a multi-factor formula combining the peak average value based on the average value of the 6-h storm and the average gradient of the main river channel to measure the discharge with the characteristics of the storm and the watershed (Shepard et al. 1993). This is represented as follows:

$$ {Q}_p={K}_{6p}^n{F}^{\alpha }{H}_{6p}^{\beta }{J}^{\gamma } $$

(3)

In formula (3), F is the design watershed area (km^2); J is the river course decline (‰); Q_p is the peak flow rate with a design frequency of% (m^3/s); π, α, β, and γ are the empirical indices of district synthesis.

Sensitivity calculation of bridge parameters

The local sensitivity analysis method is also called the fluctuation method. The sensitivity analysis is usually the method used. Its characteristic is the time of the parameter, rather than analyzing multiple parameters at the same time. The checklist is the formula, and the parameter changes are analyzed at the same time. Other parameters are used with fixed calculation method, which has fast and powerful operability (Strelkoff et al. 1999). The sensitivity coefficient, that is, the ratio of the change of the calculated model result to the change of a single parameter, is as follows:

$$ \mathrm{S}=\mathrm{dv}/\mathrm{dp} $$

where P is a certain parameter that needs to be analyzed for local sensitivity; S is the sensitivity corresponding to parameter P; v is the result parameter of the calculated model.

The change of the design flood flow with the disturbance of various influencing factors is expressed by the sensitivity coefficient, namely:

$$ \left|{Q}_p\right|=\frac{\varDelta Q/Q}{\varDelta p/p} $$

(4)

In formula (4), Δp is the disturbance to the parameter P; Δp/p is the rate of change of the parameter to make the disturbance; |Q_p| is the sensitivity corresponding to the parameter P.

Qualitative analysis of parameter sensitivity

The longitudinal gradient refers to the elevation difference between the river bottom or water surface at the two ends of the selected river section. The longitudinal gradient refers to the decline per unit length of the waterway, which is also called the gradient. The slopes of the river sections along the route are different. Generally speaking, the discriminative weighting method is used to calculate the average gradient of the river channel, calculated as follows:

$$ J=\left[\left({h}_0+{h}_1\right)\ast {l}_0+\left({h}_1+{h}_2\right)\ast {l}_1+\cdots +\left({h}_{n-1}+{h}_n\right)\ast {l}_{n-1}-2{h}_0\ast L\right]/{L}^2 $$

(5)

where J is the longitudinal slope decrease of the river course (%); L is the full length of the river section (m); h₀, h₁,...,h_(n-1) is the elevations of various points along the river bottom from downstream to upstream (m); l₀, l₁,...,l_(n-1) is the distance between two adjacent points (m).

According to formula (5), the river gradient obtained according to the discriminative weighting is affected by the discriminative point and the decision value of the discriminative value, so the river gradient is uncertain. Watershed area is also called catchment area, which refers to the area surrounded by watershed, and the uncertainty is very high.

Results

Bridge image extraction based on remote sensing images

As shown in Figure 1, after the image segmentation is completed, in order to extract the potential area of the bridge, the next rule set is determined. The normalized water index (NDWI) proposed above is used to distinguish between water areas and non-water areas. In the non-water surface feature, in order to distinguish road and non-road information, length/width (the ratio of length to width) is used in the segmentation of the threshold value. In order to delete the lengthy road information and obtain the potential bridge area, a membership function and density threshold function with asymmetry and main directions are set (Upadhyaya and Raghuwanshi 1999). Based on the threshold adjustment function, the threshold range of each object feature is artificially determined by experiments. In order to extract information, a rule set is gradually established. Using this rule set to extract the potential areas of the bridge can not only maintain the integrity of the bridge, but also improve the difference between the bridge and other ground features (Valiantzas et al. 2001).

Fig. 1

The process of extracting bridge potential area

As shown in Figure 2, after the extraction of the bridge area is completed, follow the steps below to extract the bridge. (1) The extraction results of the above waters and bridge areas are as follows. Output the SHP file, open it in the form of R_0 (region of interest) in the pre-processed original image, and adjust the color matching appropriately. (2) The water area and diving area of the bridge are respectively composed of binary mask maps (binary partitions), and the water surface is connected through mathematical operations of expansion and erosion. (3) Overlap the connected water surface and the potential area of the bridge, extract the bridge through the operation of the B1 and B2 bands, and overlap the original image. Figure 2 shows the bridge target extraction process. The final extraction result is very consistent with the actual bridge.

Fig. 2

Bridge extraction process

It can be seen from Table 3 that by comparing the extraction result of the bridge target with the visual interpretation result of the original image, it can be found that the shape and position of the extracted bridge target are better consistent with the actual bridge (Vatankhah et al. 2010). However, due to the spectral characteristics of various ground objects and various detailed effects, the shadow of the bridge itself is mixed with the water area, and there is a slight misclassification (Walker 1989). The accuracy analysis module of Envi5.1 is used to analyze the accuracy of the results of the single threshold method, the most likelihood method, and the object-oriented method in the two research fields. As shown in Table 3, the accuracy of object-oriented bridge information extraction is much higher than other methods (Walker 2005). In summary, the object-oriented extraction method in this paper has high accuracy and can extract bridged targets with different characteristics, and the positioning is relatively accurate (Walker and Busman 1990). The extraction result is a high-precision small error, which may be consistent with the actual bridge target to a certain extent.

Table 3 Accurate comparison of different extraction methods

Sensitivity analysis of bridge parameters

As shown in Table 4, by comparing the extraction result of the bridge target with the visual interpretation result of the original image, it can be found that the shape and position of the extracted bridge target are better consistent with the actual bridge. However, due to the spectral characteristics of various ground objects and various detailed effects, the shadow of the bridge itself is mixed with the water area, and there is a slight misclassification. The accuracy analysis module of Envi5.1 is used to analyze the accuracy of the results of the single threshold method, the most likelihood method, and the object-oriented method in the two research fields. As shown in Table 4, the accuracy of object-oriented bridge information extraction is much higher than other methods. In summary, the object-oriented extraction method in this paper has high accuracy and can extract bridged targets with different characteristics, and the positioning is relatively accurate. The extraction result is a high-precision small error, which may be consistent with the actual bridging target to a certain extent.

Table 4 Comparison of sensitivity coefficients of various parameters when the design frequency is 1%

It can be seen from Fig. 3 that a proper span distribution can obtain a better aesthetic effect. The split span layout of multi-span bridges should take into account the ratio of pier height and span. The ratio of the pier height to the span should be greater than 1/5; otherwise the bridge’s spanning feeling will be reduced, showing the feeling of being close to the ground. The ratio of pier height to span from top to bottom shown in the figure is 3/5, 1/5, 3/20, and 1/40, respectively.

Fig. 3

Schematic diagram of the influence of pier height and span ratio on bridge spanning sense

Discussion

General principles of bridge modeling design

The concept of Bauhaus gives infinite inspiration to the design of bridges. The bridge design of the old times, like the art form of the old time, also requires criticism to develop. The most fundamental aspect of the design of the bridge is its function. The shape of the bridge from large to small and the form of each component should have its rationality. The function of the bridge is mainly divided into structural force function and use function. The force function of the structure means that the type of bridge component adopted must meet the requirements of its mechanical performance. This aspect is embodied in the combined arrangement of components to obtain better structural rigidity and strength, such as the double limb thin-walled pier of continuous rigid frame bridge, the tower tie beam of main tower of cable-stayed bridge or suspension bridge with double cable planes, the inward inclined arch rib of basket arch bridge, etc., on the other hand, it is reflected in the shape of the components, such as A-shaped, H-shaped, inverted Y-shaped, drop-shaped, vase-shaped, and other shapes of main towers and square and round piers. The selection of these different forms of bridge components is designed based on the rationality of their forces, and the current “topological form finding” method is to start from the most fundamental force analysis to find the necessary and extremely streamlined shapes. Each form of the same type of component has its own advantages and shortcomings. The selection of bridge components requires the first in terms of mechanical function. The clear communication of force is the foundation of bridge beauty.

The use function is the durability and maintainability of the structure type used. The durability of bridge structures is now a hot topic. It has spawned a series of research activities on bridge structure life span monitoring, inspection, maintenance, and reinforcement. In the past 30 years or so, domestic infrastructure construction has developed rapidly. After many years of inspections, the engineering projects during this period have found many problems such as cracks and excessive deformation. Such as the double-curved arch structure that has been widely admired for a period of time. Taking into account its better mechanical properties and the ease of construction that can be divided into parts and then integrated into parts, it is largely adapted to the level of construction technology at that time, so it has been widely disseminated. However, it was later discovered that it was precisely because of too many scattered components and the immature construction technology that the final structure was poor in integrity, and a large number of key joint parts cracked and failed, and the safety of the structure was at risk. As early as many years ago, the double-curved arch bridge was not allowed to continue to be built. It can be seen that the durability of the bridge is not only reflected in the initial design, but also in consideration of the actual construction situation. The design should be considered an important indicator, which is important for bridge construction.

The normal use and maintenance after completion plays an important role.

Only when it becomes the expression of formal meaning can the external profile achieve its purpose. Kandinsky’s views on form and internality are reflected in the form and function of the bridge structure. There is a close connection between functional requirements and appearance form. There is no doubt about this, except for landscape bridges. Except for the bridge structure with the main modeling characteristics, ordinary bridges should maintain a sincere appearance; that is, the form of the force should be fully displayed; that is, the form should reflect the function. This is not only an important source of psychological stability for the viewers; it also has a positive effect on the assimilation of the bridge shape. The vague force system, that is, the false external form, will only bring the viewer elusive and unstable feelings. In this way, the beauty of the bridge is also it became an empty talk.

For color, there are two important indicators, namely brightness and warmth, which are also the most direct and strongest color factors perceivable by the human body. Lightness refers to the degree of lightness and darkness of a color, and colors of the same hue may have different lightness and darkness. Bright colors and warm colors express the visual effect of stretching forward to approach the viewer, while dark colors and cool colors move backward and away from the viewer. The French impressionist painter Claude Monet paid great attention to exploring the field of color. His representative work “The Haystack” has a small area of ​​sporadic warm colors but continues to extend forward, and even as the haystack shadow at the center of the painting, because of the cold color retreating consciously, the picture has a strong sense of depth.

The Russian artist Kandinsky initially divided colors into four basic tones, namely bright warm colors, dark warm colors, bright cool colors, and dark cool colors. He thinks warm colors are yellowish, and cool colors are blue. From a monochrome point of view, yellow produces a sensation of spreading outwards and approaching the audience, with a stinging sensation; blue is constantly shrinking inward, with a sense of suction. The yellow is exaggerated, and the blue is deep and restrained. Red is passionate and unrestrained, condensed in firm and strong centripetal force. The characteristics of the three colors will produce richer changes when mixed with each other. Yellow and blue are in extreme sensory opposition, so the green that is mixed tends to be quiet and stable; the orange that is mixed with red and yellow is actually the red that is pulled by the yellow to further approach the viewer, with a strong vision attraction; red and blue when mixed turn into purple; it is a kind of cooled red, with the characteristics of morbidity and decay. In addition to the three primary colors and their complementary colors, there are also black and white colors as special existences, which are the end points of light and dark. Black is a dead silence without any possibility, a sign of the end and the beginning. Both black and white are neutral tones. White is an infinite void, pure, and full of unknowns. The gray formed by mixing black and white has basically lost its vitality. The stillness of gray is different from that of green, and it is lifeless. As the brightness decreases, gray even gradually conveys the feeling of desolation and depression, while the brightened gray can get a sense of breathing and bring back vitality. In addition, each color tone will bring a different feeling to the original color after more or less other colors are added. For example, vermilion and crimson with red tones have completely different emotional characteristics from scarlet. The vermilion red is like flowing molten steel, which condenses when it meets water, while the deep red lacks vitality. It has become a cool color but still has a warm feeling. The color combination generates momentum. The generation of this momentum comes from the cold and warm colors and the light and shade, but the movement between the colors caused by the light and shade is more compulsive. And the light and shade will strengthen the momentum caused by the cold and warm. When matching colors, there will be a very strong contrast between colors that are complementary colors. When appropriate, the combination of complementary colors can form a strong visual impact. If they are not properly matched, it will be counterproductive and cause strong rejection from viewers. The color selection of the bridge should be selected based on the environment in which it is located. In order to keep the bridge simple and neat and avoid dazzling people, it is advisable to choose no more than two colors for the bridge.

Design of the main components of the bridge

It can be seen from Fig. 4 that a proper span distribution can obtain a better aesthetic effect. The ratio of pier height to span from top to bottom shown in the figure is 3/5, 1/5, 3/20, and 1/40, respectively.

Fig. 4

Schematic diagram of the influence of pier height and span ratio on bridge spanning sense

(From top to bottom, the mid-span ratio is 1.3, 1, 0.6, and 0.4.)

It can be seen from Figure 5 that for a variable sorghum bridge, the bottom of the beam presents a feeling of jumping, and the ratio of the height of the pier top beam to the mid-span beam height is determined to be between 1.3 and 2.5 to achieve a better visual effect.

Fig. 5

Schematic diagram of the influence of the mid-span span ratio of the equal sorghum bridge on the aesthetic effect

(From top to bottom, the mid-span ratio is 1, 0.7, 0.6, 0.4, and 0.3.)

It can be seen from Figure 6 that due to the relatively simple structure of the beam bridge, simplicity is the key to achieving a better aesthetic effect of the beam bridge. Excessive beam height and vertical lines will destroy the effect of horizontal and longitudinal extension. For the equal-sorghum bridge, the solid guardrail presents the same effect on the elevation as the main beam height. Therefore, the height of the solid guardrail should be taken into consideration when splitting holes in the ratio of beam height to span to avoid a top-heavy look. Another treatment method is to use transparent guardrail form. For the sorghum bridge, the bottom of the beam presents a feeling of jumping, and different curves of the bottom of the beam present different sense of rhythm and tension, conveying different feelings. The ratio of the pier top beam height to the mid-span beam height is determined to be between 1.3 and 2.5 to achieve a better visual effect.

Fig. 6

Schematic diagram of the influence of the mid-span ratio of the variable sorghum bridge on the aesthetic effect

It can be seen from Figure 7 that the cantilever of the beam can be lengthened. Under sunlight conditions, a longer cantilever will produce a larger shadow area on the beam. Because the dark color will produce the effect of retreat, it becomes inconspicuous visually, and it can give people the illusion that the beam has become thinner. Take the box beam as an example. Similarly, when exposed to sunlight, the upper beams will create larger shadows on the facade than the lower beams and appear slimmer in terms of visual effects.

Fig. 7

Schematic diagram of the influence of the length of the cantilever plate on the visual height of the same beam height

It can be seen from Figure 8 that the design of the bridge piers should remain coherent and uniform as a whole; that is, the same modeling elements should be adopted, and minor adjustments should be made when necessary. The ratio of the width of the pier along the bridge to the height of the main girder should be between 0.25 and 0.5. For a single T-shaped pier column, the height of the cantilever root should not be less than the width of the pier column along the bridge; the width of the pier column in the transverse direction should be about 1/4 of the width of the pier top in the transverse direction; the height ratio between the cantilever end and the root should be appropriate around 0.5. For double T-shaped piers and multi-T-shaped piers, the transverse width of the pier column should be 1/10 of the width of the pier top: the height difference between the root of the inner cantilever and the connection of the inner cantilever should be 1/4 of the height of the cantilever root. In expressway bridges, the shape of the piers should be kept as simple as possible and not complicated. The sides of the piers are the most commonly seen in the three-dimensional intersection of highways. When the length of the cap beam of the multi-pillar pier is greater than the height of the pier, the number of pier columns should be controlled or a pier column with better permeability should be adopted; when the length of the cap beam of the multi-pillar pier is less than the height of the pier, the size of the pier bottom should be increased And make an appropriate transition. The treatment method for slab piers is similar.

Fig. 8

Schematic diagram of the effect of rounded corners and cut corners on the visual height of the main beam with the same beam height

It can be seen from Figure 9 that the design of the abutment mainly takes into account factors such as the span and height of the main girder and the height of the space under the bridge and strives to balance the mass. The exposed height of the abutment should be kept within a certain range, and the lowest exposed height of the abutment at the beam end support position should not be less than 1/2 of the height of the main girder. For bridge towers that are too exposed, their visual volume should be appropriately reduced. The available methods are line and surface material treatment.

Fig. 9

Schematic diagram of the effect of scribing on the reduction effect of abutment volume

It can be seen from Figure 10 that the principle of line processing is also the optical illusion effect. When the horizontal and vertical lengths are the same (ab), the horizontal stripes can make the vertical length of the shape longer, that is, a <b; the vertical stripes can make the horizontal length of the body longer, that is, a >b. In addition, as the density of horizontal or vertical stripes increases, the optical illusion effect will be reduced.

Fig. 10

Schematic diagram of visual illusion effect caused by stripes (a=b)

It can be seen from Figure 11 that if the abutment is too large due to the short bridge abutment in the design, visual illusion can be used. Due to the effect of visual illusion in Figure 10, the main beam appears longer, and the space under the bridge is more open, with a better view, and a good aesthetic effect has been achieved. For example, the Neris River in Lithuania is a good example. Its slender bridge body and the heightened main girder allow the space under the bridge to be preserved to the utmost extent and achieve a good landscape effect. The caps are sometimes exposed, and their influence on the shape of the bridge cannot be ignored. The horizontal cross-sectional shape of the cap and the horizontal cross-sectional shape of the pier column should correspond to each other; that is, if the pier column is treated with rounded corners, the cap should also be treated with rounded corners. The same is true if corner chamfering or facade engraving is used, in exchange for a coordinated response effect.

Fig. 11

Schematic diagram of the effect of the abutment with the bottom shrinking outward

Bridge modeling design effect and evaluation

Analysis of the effect of bridge modeling design

As the most eye-catching existence of the long-span suspension bridge, the pylon must be the focus of the modeling design. The pylons of the Cuntan Yangtze River Bridge use the word “open” and the concept of archways to integrate traditional Chinese cultural elements into modern bridges. This is understandable, but appropriate methods need to be adopted when combining them.

There are many types of archways, but when using them, attention should be paid to the coordination and beauty of the proportions. The shape of the pylon of the Cuntan Yangtze River Bridge is similar to that of the most primitive Hengmen, which is a relatively simple archway. But from the perspective of the appearance of the archway, the excessively long pylons have caused serious imbalance in proportions and lost the aesthetics they should have. From the perspective of the bridge tower, although the force is calculated to meet the requirements, the corbel structure formed by the cross beam of the main tower extending through the tower column is still unfavorable to the force of the main tower. According to the Bauhaus design theory, form and function should be consistent and concise. In addition, the use of decorations should also be reasonable. Chinese knot decoration not only helps the bridge itself and the coordination with the surrounding environment, but also increases the burden on the main tower. Such decorations should be avoided. In addition, considering the densely vegetated mountains as the background, in order to minimize obscuration, a more concise form of bridge tower should be used. The upper part of the pylon of the Cuntan Yangtze River Bridge is more complicated, and the Chinese knot decoration further reduces its permeability, forming a barrier. Combined with the aforementioned method of design guidance for cable load-bearing bridges, each part of the main bridge will be evaluated separately.

Overall review

Whether the bridge is beautiful or not cannot be measured by a single, absolute standard. People’s aesthetic orientation will gradually change as the times change. Most of the ancient beam bridges and stone arch bridges were decorated with certain sculptures, which was the mainstream modeling technique at that time. After several years of history, these bridges have also shown a different kind of beauty, and they have been praised today. However, it is worth noting that these ancient bridges were built in accordance with the times when the surrounding buildings or natural scenery were suitable. The environment and aesthetic tendency of people today are very different from those in the past, and the design techniques of modern bridges are bound to be very different from the past. Naturally, the use of decorative objects cannot continue to be directly stacked, and traditional elements need to be more euphemistic. Modern technology is merged. The development of modern design theory has provided many new methods for the design of bridge modeling. There are also many experts and scholars in the industry dedicated to the research of this area, providing unlimited possibilities for the design of modern and future bridges, but what remains unchanged is that the beauty of the bridge must be built on coordination. After field investigations, only the west side has the conditions to build ground anchors, and Babin Road on the east bank has built new high-rise residential buildings and commercial streets. The ground anchors can only be installed under Binjiang Road. However, due to the low terrain, flood levels sometimes occur. Because of the risk of being submerged, it is not advisable to build ground anchors on the east bank. Self-anchored suspension bridges can avoid this problem. The Egongyan Yangtze River Bridge double-track bridge chose a self-anchored suspension bridge system when ground anchors could not be built. However, because its location is close to the Chongqing Egongyan Yangtze River Bridge, which has been in service for many years, a similar appearance was adopted for coordination with it. A self-anchored system with similar shape is adopted for coordination. There are no other bridges near the proposed bridge location of Huangjueping Yangtze River Bridge. The aforementioned Egongyan Yangtze River Bridge and its double-track bridge can only be seen at the 4 supporting points. However, the distance is too far and visually integrated with the building in the distant view; it has little impact on the new bridge. Since the self-anchored suspension bridge must be built after the main girder can be anchored at its ends, the most commonly used construction method is to erect a temporary main tower on the top of the tower after the main tower is completed and complete the cantilever by staying cables. Assembling or pouring, after the main beam construction is completed and the main cable is anchored, the temporary main tower is demolished, which is costly and complicated in construction. If you have the conditions to build a full hall under the bridge, you can achieve a certain degree of economy. However, the Huangjueping Yangtze River Bridge has frequent navigation and a large traffic volume, and it is more feasible to build a full hall in the center of the river. In contrast, a cable-stayed bridge system with strong economy and convenient construction is a more suitable choice. The overall rigidity of the cable-stayed bridge is large. Compared with the suspension bridge with flexible main cable, it can better reflect the perseverance and stubbornness in the bones of the old Chongqing people (National Engineering Handbook 1974).

The design of modern bridge components must be based on the rationality of their existence. In the modern bridge design concept that promotes simplicity, lightness, and thinness, bridge decorations such as sculptures and reliefs have been difficult to adapt to today’s aesthetic standards. The answer to how the various parts of the bridge itself can be concise and thin has been answered in the Bauhaus ideological system that appeared in the early twentieth century. By applying the Bauhaus thought system to the design of bridges, this paper has formed the guiding principle of bridge design with function as the leading factor. The beauty of bridges must be based on the understanding of coordination. Coordination is the foundation of bridge beauty, and artistry is the highest pursuit of bridge design (US Department of Agriculture et al, 1974). But the creation of art is not enough to rely solely on beauty or coordination. It also requires the talent and creativity of designers. Regarding this point, since most colleges and universities in China have not incorporated aesthetics education into the education of engineering students, most bridge designers with engineering backgrounds do not have a deep enough understanding of the aesthetics of bridges. Even if a designer with a background in art and a bridge designer work together to complete the project, it is often difficult to achieve the desired effect. Due to differences in thinking modes and unfamiliarity with each other’s professional content, there are bound to be huge obstacles to communication between the two. Therefore, only by combining bridge engineering technology and artistic literacy can it be possible to truly create a masterpiece of bridge art. I would like to propose to add art courses to the training of engineering education. It is expected that the seeds of art will be planted in the hearts of engineering students and will become bridge engineers with both skills in the future.

Conclusion

Traffic target recognition based on remote sensing images is one of the important technologies of automatic target recognition theory. The representative targets of this investigation mainly include different levels of roads, bridges, highways, and other transportation hub identification methods. The process of the recognition method mainly includes edge detection (low-level processing), line primitive extraction (medium processing), line primitive connection, and target description and extraction (high-level processing). In addition, in order to identify urban roads from high-resolution remote sensing images, this paper uses the method of extracting block edges to achieve road extraction. This breaks the idea of ​​extracting the features of the line. First, apply multi-resolution image fusion based on wavelet transform to obtain multi-resolution image fusion. Then, the SMKE operator and the Sobel operator are used to detect the contour of the object in the low-frequency sub-state image. In other high-frequency sub-images, wavelet-based symbols are applied, and a method of connecting line elements of remote sensing images in different resolutions and different scenes is proposed. According to the linear characteristics of roads, the principle and implementation of phase marking and Radom transform as the two most representative original extraction methods are analyzed, and an improved road extraction algorithm based on directional statistical features is proposed, which takes linear features into account. The experimental results show that the former has a good effect on the extraction of ordinary line objects, and the latter has a good effect on the extraction of roads from open terrain with low-resolution images. The road target recognition method based on remote sensing images is being studied extensively.