Practice direction: road and bridge engineering

Internship location: *

Internship time: 7.21-7.25.

Lecturer: * */* *

Intern students: * */* * Class/* * *

First, the purpose of internship

Graduation practice is an integral part of the whole graduation design teaching plan, and it is also an important practical field of civil engineering specialty. By organizing visits and listening to some special technical reports, we can collect some information and materials related to graduation design, which will lay a solid foundation for the smooth completion of graduation design. Through practice, the following objectives should be achieved:

1, understand the whole design process of general industrial and civil buildings or road and bridge projects;

2. Understand the general layout of the building, the classification and function of the building, the types and characteristics of the structure, the arrangement of structural members and the load transfer route, the details of the main node structure and the treatment methods. ;

3. Understand the construction methods of buildings;

4. Understand the relationship between architecture, structure and construction;

5. Understand the latest trends and development direction in the field of building structure.

Second, the practice method, place and content

According to the practice plan and schedule of the teaching and research section of road and bridge engineering, we conducted a five-day graduation practice, which was transferred to the construction site of Tianxingzhou Bridge in Wuhan and the stations along Wuhan light rail. The specific practice methods and places are as follows:

Date, week, method and place

3.2 1 A short film, Bishop of Engineering Department of Wuhan University

3.22 The second on-site inspection of Tianxingzhou Bridge construction site

3.23 Three technical reports of Tianxingzhou Bridge Construction Office

3.24 Four field trips along Wuhan Light Rail.

3.25 Lecture by Bishop of Five Engineering Departments

First, short film observation

In the morning, I mainly watched some road and bridge projects across the sea, river and river, and briefly reviewed the construction technology and process. First, the planning and design of Kaohsiung-Danshui Expressway in Taiwan Province Province. Through the demonstration of the plan, this project introduces the location of each mid-point city, the topography along the way and the connection of each branch road, and considers to build an expressway network along the island to connect with it, which is also outstanding in environmental protection. Specially, animal and plant experts are hired to evaluate and test the impact on the environment during and after the construction of this project, and their research results are considered in design and planning. This is obviously not enough in China. Later, I contacted the records of road construction and arch bridge construction in the United States and other countries one after another, and got a preliminary understanding of the new technology and new technology of road and bridge.

In the afternoon, I continued to watch slides, in which the construction process of Yangluo Highway Yangtze River Bridge was simulated with dynamic and realistic three-dimensional animation, and the learning effect was obvious; Since then, the initial demonstration of the Shinkansen project in Tohoku, Japan and the construction of a large highway bridge in Thailand, although there are certain language barriers, still achieve multiple goals of cognition, learning and thinking because of the detailed system and repeated playback of the pictures.

The following briefly introduces the construction work of the above three projects in turn:

1, Yangluo bridge system is a suspension bridge. Jiangsu Runyang Yangtze River Bridge currently under construction has a span of 1.490 m, making it the third largest suspension bridge in the world. The characteristic of suspension bridge is that it can span an unparalleled long span of other bridge types, and because of the simple and clear force, the rolled steel basket is convenient for transportation. After the cable is erected, a solid and stable structural support system can be formed, and the risk in the construction process is relatively small. The specific construction process of slide show of Yangluo Bridge is as follows:

(1) face surface treatment;

(2) the construction of the excavation groove section;

(3) North anchorage construction;

(4) Cable tower construction;

5] template pouring concrete tower;

[6] Installation of cable system of main bridge and installation of bridge segments.

Because the soil quality of the north and south banks of Yangluo Bridge is different, the construction scheme is different, and the soil quality of one side of the bridge is good, so it can be directly excavated. On the other hand, it belongs to sandy muddy soil, and concrete should be excavated downward at the excavation outer diameter of the ingot to make a retaining wall. It is particularly important to pay attention to process (2) and process (5). The former excavates and pours concrete from top to bottom to prevent collapse; The latter is caused by excessive hydration heat in mass concrete construction, which should be controlled.

2. Tohoku Shinkansen Project in Japan

This paper introduces the construction method of moving formwork used in the Shinkansen project in Tohoku, Japan. The method is to pour the bridge hole by hole by using mobile scaffolding and assembled formwork. It consists of bearing beam, guide beam, trolley, pier support and formwork. Load-bearing beams and supporting templates are set on both sides of the box girder to bear the construction gravity. The length of the guide beam is longer than the span of the bridge, and the bearing beam is supported on the pier when pouring concrete. The guide beam is mainly used to transport load-bearing beams and movable formwork, so it needs twice the span of the bridge. After the construction of one-hole beam is completed, demoulding and frame unloading are carried out, and the load-bearing beam and movable formwork are transported to the next bridge hole by the guide beam and the front and back trucks on the completed bridge. After the bearing beam is in place, move the guide beam forward.

3. Construction of large highway viaducts in Thailand

Through long-term exhibition and detailed introduction to the construction site by slides, it is shown that the pier and abutment of the bridge are cast in site and the beam section of the bridge body is prefabricated by the factory. Its advantages are that the upper and lower structures of the bridge can be constructed in parallel, which greatly shortens the construction period, and there is no need to manufacture components at high altitude, the quality is easy to control, and it can be mass-produced in one place, which reduces the engineering cost. But the disadvantage is that it needs large hoisting and transportation equipment. Obviously, due to the longitudinal joints between components, the overall working performance of spliced components is not as good as that of cast-in-place method.

B.tianxingzhou bridge

1, project overview

Wuhan Tianxingzhou Yangtze River Bridge is located in the first line from Qingshan District to Chenjiaji in Hankou, about 9.5 kilometers away from the upstream Wuhan Yangtze River Bridge. It is a key construction project of the tenth five-year plan, which is jointly built by Hubei Province and the Ministry of Railways. The bridge was officially started on September 28th, XX, and the contract completion date was August 3rd, 20081day.

The total length of Tianxingzhou Yangtze River Bridge in Wuhan is 4657. 1m, and the section from Qingshan Bank to Hangang is a 40.7m box girder (98196 504196 98) cable-stayed bridge with 40.7m steel truss girder (54.2×80 54.2 Among them, the combined construction of public railways is 2842. 1 m, which is undertaken by China Railway Bridge Bureau Group Co., Ltd.

2. Main bridge structure

The main bridge of Tianxingzhou Yangtze River Bridge in Wuhan is a (98 196 504 196 98)-meter steel truss girder cable-stayed bridge with twin towers and three cable planes, with a length of 1092 meters. The upper highway has 6 lanes and the bridge deck is 27 meters wide; The lower railway is designed in four lines, including two I-class trunk lines and two passenger dedicated lines. The main girder is a plate-truss composite steel truss, an N-truss and three main trusses, with a width of 2× 15m, a height of 15.2m and an internode length of 14m. The main tower adopts concrete structure, inverted Y-shape, and the height above the pile cap is188.5m. There are 3× 16 galvanized parallel steel wire stay cables on both sides of the main tower. The cable section is 45 1φ 7mm, and the cable tension is about 1250 tons. The foundation of the main tower is about φ 3.4m bored pile, with 32 piers No.2 and 40 piers No.3, and the pile caps are constructed with double-walled steel cofferdam. The bridge integrates the "four new" technologies of new technology, new structure, new technology and new equipment, and is a landmark project of a new level in China's construction.

3, engineering innovation and characteristics

⑴ Long span of main bridge: The main span of cable-stayed bridge is 504m, which is the first span of * * * bridge in the world.

⑵ Heavy bridge load: This bridge is the world's first highway-railway cable-stayed bridge built according to the four-line railway, which can bear 20,000 tons of load at the same time, making it the world's largest highway-railway bridge.

⑶ Fast design speed: This bridge is the first iron in China.

For the long-span cable-stayed bridge of passenger dedicated line, the design speed of passenger dedicated line is 200 km/h, and the dynamic simulation design is carried out according to 250 km/h.

(4) New structural type: This bridge adopts a new structural type with three main trusses and three cable planes for the first time; The highway deck adopts orthotropic slab or the combined system of concrete and steel truss, and the railway deck adopts the combined system of concrete and steel truss. The main tower is equipped with a large-tonnage hydraulic damping device to limit the longitudinal displacement of the beam.

5. New construction technology: the new technology of precise positioning of prestressed anchor pier of giant double-wall steel box cofferdam is adopted for the first time for the pier foundation of No.2 main tower; The pier foundation of No.3 main tower adopts the floating positioning heavy anchor construction technology of giant double-wall steel hanging box cofferdam; For the first time, a power head drilling rig with torque of 30tm was developed for the construction of φ 3.4m large diameter bored pile.

[6] Construction difficulty: The overall manufacturing, horizontal launching, floating transportation and positioning construction of the giant double-walled steel cofferdam factory with a plane size of 70m× 44m are the first in China, with high technical requirements. The plane positioning accuracy of cofferdam is within 5cm, and the verticality of steel casing is within 1/500; Construction of φ 3.4m large-diameter bored pile in conglomerate with uneven soft and hard cementation: 16000 mass concrete construction and control of square platform: the fabrication and installation of new three main trusses and new plate trusses have high construction precision, strict technical requirements and great construction difficulties; 45 1 φ 7mm long 27 1m galvanized parallel steel wire stay cable fabrication and installation; Vertical construction control of main tower with a height of 188.5m and spatial positioning of cable ropeway pipe: integral cast-in-place construction of large-tonnage box girder with its own weight of 2× 1300 tons.

4. The key technical research and test items of Tianxingzhou Yangtze River Bridge have been reduced from 65,438+07 to the following 65,438+00, namely:

⑴ Analysis and research on dynamic characteristics of live load standard of four-line railway;

⑵ Seismic analysis and research of large-tonnage hydraulic shock absorber;

⑶ Wind-resistant performance and simulation experiment research;

⑷ Experimental study on railway concrete steel truss bridge deck system;

5. Spatial structure behavior and stability analysis of cable-stayed bridge with three main trusses;

[6] Experimental study on structural fatigue performance;

(7) Large-scale model test of typical joints;

(8) Development of temperature expansion regulator for large displacement track and expansion device for beam end track;

(9) Development of large-tonnage and large-displacement bearings;

⑽ Experimental study on new technology of building manufacturing.

We mainly investigate the construction of No.3 main pier. As mentioned above, the foundation of No.3 main tower pier adopts the construction technology of giant double-wall steel cofferdam with integral floating and heavy anchor positioning, and adopts 40 φ 3.4m bored piles with a pile length of 80.4m and a hole-forming depth of10/m-102m, reaching the underground rock foundation. Because the hole-forming depth and hole diameter are the highest in China, China Railway Bridge Bureau specially organized a technical public relations team to develop a power head drilling rig with torque of 30tm for the first time, which was used for the construction of φ 3.4m large-diameter bored piles.

On the third day of practice, Teacher Zhang gave us a technical report with high gold content. Finally, he gave us a meaningful sentence: never be satisfied with bridge technology. It is a spur and an incentive, which should be the unremitting ideal and pursuit of every bridge designer and builder.

C. Wuhan rail transit

The second stop visited the first phase of Wuhan light rail project, with a total investment of 265,438+99 million. The total length of the project is 10.234 km, and there are Zongguan and Pacific stations 10 along the way. It was completed and put into use in July of XX. It was originally equipped with the 12 train. Each train has 4 carriages and can carry 950- 1200 passengers. The average speed of design and operation is 34.5 kilometers per hour, and the speed can reach 80 kilometers per hour. Due to the short distance between the two stations, the actual speed is only 50 kilometers per hour, but its average speed is still higher than that of ordinary road traffic vehicles. It only takes 17 minutes from Huangpu Road to Zongguan Waterworks.

The first phase of light rail 1 Line adopts integral viaduct, and the pier adopts box-type simply supported beam structure. Its construction technology adopts ballastless track construction, and the process flow is as follows: bridge deck treatment-benchmark measurement-turnout rail material on the bridge-paving turnout rail-turnout support block on the bridge-connecting turnout rail-erecting turnout and aligning fittings-supporting block on the bridge-coarse adjustment of turnout rail state-steel bar binding and welding-fine adjustment of turnout-rail state inspection-pouring piers-dismantling support frame-rail state inspection-rail bearing platform template assembly.

At the intersection of this project and Beijing-Guangzhou railway, the elevated height becomes larger. Considering the control of train height in the future, the traffic standard of double-deck freight cars is adopted. The technicians repeatedly explained the construction situation of the intersection here: they specially reported to the railway department for approval, and won the Beijing-Guangzhou line to be interrupted for two hours at night to win valuable construction time. The light rail is divided into two lanes after crossing, and its platform is located in the middle, which is called "island station". At Zongguan Station, the project has set up a vehicle lane, and the track has been adjusted accordingly to adapt to the traction power of the double-headed car.

How to organize effective construction emergency repair and how to properly handle official business is something that every technician should study hard while guiding on-site construction.

D. Special lectures

We are honored to invite Dean Xu from the Fourth Survey and Design Institute to give a special report. Director Xu elaborated on the qualities that professional engineers and technicians should possess as follows:

A, there must be a clear inauguration goal, principle: jump up and reach it;

B, from now on, cultivate good qualities (thought-behavior-habit-character-destiny);

C, cultivate good thinking methods and clear thinking;

D, be good at grasping opportunities;

E, properly handle interpersonal relationships;

F, in a society with a clear division of labor, we should do our respective duties;

G, correctly treat "name" and "profit";

H, cultivate the ability of combining learning, writing, theory and time;

First, the ability to face pressure and deal with difficulties;

J, improve cultural taste;

K, love civil engineering and career.

Subsequently, we had a wide and enthusiastic exchange on matters related to employment and career selection and related professional theoretical knowledge. Many of his suggestions and experiences are of high reference value, and we have benefited a lot.

Third, the internship summary

Although the internship time is short, it basically achieves the multiple purposes of collecting data for graduation design, perfecting the knowledge learned and integrating theory with practice.

In the practical project, we learned the whole process and general steps of road and bridge engineering design, the new trend and new method of structural design, and the related construction technology.

The essence of internship is a simulation exercise before graduation, and it is very important to sharpen it when you are about to enter the society and set foot on the job. I hope life can be extended from this, and I can really apply what I have learned.