What are the main contents of civil engineering practice?

Understanding practice is the first practical teaching link of civil engineering, which helps me to establish correct professional thinking and correct attitude towards professional knowledge learning. During the four-day trip, we carried out the principle of integrating theory with practice and went deep into the construction site to learn knowledge, which made us understand the vast field of civil engineering-not only civil engineering, but also bridges and tunnels, which helped to stimulate our curiosity and cultivate our interest in professional courses.

First, the purpose of cognitive practice:

1, get a preliminary understanding of general industrial and civil buildings, roads and bridges and related construction technologies before construction;

2. Cultivate students' interest in civil engineering and further deepen and consolidate their knowledge through practice;

3, through personal participation in construction practice, cultivate the ability to analyze and solve problems independently;

4, understand the basic production technology of building construction;

5. Understand the actual level of construction technology and construction organization management in China at present, and put forward some new construction and management methods according to the actual construction management.

Second, the internship location and project overview:

Day 1: Construction site of Xinxin Expressway in Xincai County, Zhumadian

This project mainly adopts pile foundation, and the pile adopts reinforced skeleton. The underground part is called pile, and the above-ground part is called column. Once you start pouring piles, you can't stop it no matter what the weather is. Once the grouting interval exceeds 40 minutes, it is considered as broken pile and abandoned pile. After pouring, the pile can be detected by acoustic wave, and whether there are cracks or faults inside can be judged according to the shape of acoustic wave. The requirements are extremely strict. After the formwork is removed, it will be poured at one time without artificial decoration. If bubbles, rough surface and other problems affect the appearance of the column, the column will be sandblasted and reprocessed. So the pillar we usually see is what it looks like when it is formed. After the column is molded, it should be wrapped with a special moisturizing film. The column should be in an environment with water, surrounded by armor when it is cold, and attention should be paid to the insulation effect and other processes.

Some knowledge about cranes;

According to the different structures, heavy cranes can be divided into beam cranes, bridge cranes, portal cranes, mobile cranes, cantilever cranes, tower cranes, cable cranes, ship cranes, carrier bridges and so on. Beam cranes include: beam cranes mainly include single-beam bridge cranes and double-beam bridge cranes. Mobile cranes include truck cranes, wheeled cranes, chain cranes, all terrain crane and cross-country cranes.

The next day: Bihai Garden Community, Yinhe New Village, Zhumadian

This project is a low-rise brick-concrete structure with (6+F) structure. There are 7 floors in the building, and the basement is completely poured with concrete for the garage. The ground floor is made of solid bricks, and the upper floor is made of hollow bricks. Gantry is mainly used to transport building materials during construction (gantry is suitable for low-rise civil buildings, and tower cranes and other large-scale construction equipment are used for high-rise civil buildings). The main beams and columns of the commodity house are poured with commercial concrete. The construction cost and time are greatly reduced, and the engineering quality is improved.

Through the technician's explanation, I learned a lot of construction technology and common sense, and I feel benefited a lot. It is known that there are some small holes in the wall at regular intervals, which are used to erect steel pipes during construction to facilitate the construction of the wall and the upper plate. , need to backfill after completion. There is a "five zero lines" on the ground floor, which is convenient to find the horizontal line, generally 30 cm above the ground. The cross beam in the house wall is serrated, which is beneficial to strengthening the joint between the column and the wall. Increase the seismic resistance of the building wall, and add a ring beam on each floor to prevent uneven settlement. Why does the stair surface adopt step-by-step type, and the lintel on the door has the function of ring beam? Prestressed hollow slab is used for the top floor of the building, solid slab is used when the slab spacing is less than 1.2m, and hollow slab is used when it is greater than1.2m. (Both prestressed hollow slab and solid slab have certain technical requirements for their length, width and height) A gap of about 35 ~ 40mm should be left between the hollow slab and solid slab as expansion joint, and concrete should be filled to eliminate cracks. In addition, toilets and kitchens are generally poured lower than the ground, and waterproof technology is adopted, and waterproof belts are built with pouring plates in the walls. When the house was built, all the wires, pipes and drainage holes were buried in the wall. The interior is very beautiful.

The advantages and disadvantages of hollow brick and ordinary clay are compared as follows:

1. There are many kinds of hollow bricks. This paper mainly introduces a kind of direct pouring hollow brick.

This kind of brick has the advantages of light weight, high compressive strength, sound insulation, heat insulation, moisture prevention, fire prevention and corrosion resistance.

Concrete hollow block is about 1/3 lighter than red brick, which can reduce the self-weight of buildings. It can be used as load-bearing wall, especially solid concrete block, in addition to filling walls in various industrial and civil buildings. In some areas, such as Shanghai, the use of concrete blocks is more common, often replacing red bricks as load-bearing walls in brick-concrete structures. Shanghai has also successfully built a 18-storey house with reinforced concrete blocks as the load-bearing structure. However, because it is a hollow block, the performance of nailing heavy objects is slightly worse than that of solid bricks. Embedded pipes are also worse than solid masonry.

2, clay brick

The oldest state of clay brick is solid clay brick. This is one of the oldest building materials in the world, which has inherited the history of architectural civilization in China for thousands of years. However, the raw materials for firing solid clay bricks come from cultivated land. According to the data, 700,000 mu of fertile land burned in China is damaged every year. In addition to destroying cultivated land, another hazard of solid clay brick is that it consumes a lot of energy. Figures provided by relevant departments show that burning a cubic meter of solid clay brick requires120kg of coal. A large amount of carbon dioxide is produced in the process of brick burning, which also seriously pollutes the environment. At present, most provinces and cities in China have stopped using clay bricks.

Plate, beam, column, wall, foundation, arch and other components in building structure and their functions;

Beam-flexural members arranged horizontally (usually) or obliquely (stair beam) in engineering structures. According to the structural function, it is mainly divided into main beam, secondary beam, tie beam, ring beam and lintel.

Flat plate-a flexural member supported on a beam (or column or wall) to cover a plane whose length and width are much larger than its thickness. It mainly bears the vertical gravity load or wind load imposed on the floor. Usually there are horizontal placement (vertical gravity load), inclined placement (such as stair slab-vertical gravity load) and vertical placement (such as wallboard-vertical wind load). According to the cross-section form, it is divided into solid plate, hollow plate and vertical wind load.

Column-the vertical component in the engineering structure that bears the vertical pressure (mainly) and bending moment. According to the materials used, it is divided into: stone column, brick column, block column, steel column, reinforced concrete column, rigid reinforced concrete column, concrete filled steel tube column and various composite columns.

Wall-bears the pressure from beams and slabs, the self-weight of the wall, and sometimes horizontal loads.

Foundation-The structural members that transfer the loads of buildings, machines and equipment to the foundation are called foundations (such as foundations under columns and walls). They are made of brick, stone, concrete or reinforced concrete, and the foundation must have sufficient bottom area and buried depth (to ensure the strength and stability of the foundation without excessive deformation).

Arch-curved structures are mainly subjected to axial pressure, and are widely used in building construction (arch beams or arch long-span structures of brick doors and windows) and bridge (arch bridge) projects.

Day 3: Lianjiang Bridge on Yicheng Avenue in Zhumadian

The bridge has been basically completed. According to the actual measurement, this road forms an angle of 75 degrees with the river. So the bridge is made into a 75-degree oblique bridge. The construction process of the bridge mainly includes piling, pouring piles, pouring beams, pouring capping beams and paving. Commercial concrete is used for the pile foundation, and 25 # steel bars are mainly used. There are also piles with the interval of 10X 10. Above the capping beam is a prestressed hollow slab, which is hollow to reduce its own weight. Between the column and the capping beam, there is a rubber bearing, and a thin structural layer composed of rubber plate and steel plate is used to adjust the stress balance and uniformity. The hollow slab is paved with double-layer net reinforcement and concrete and asphalt. There are expansion joints between hollow plates, and materials are added in the middle. The pier is poured with concrete to prevent rain erosion. The boundary of the bridge is abutment, and the size of slab reinforcement is 25* 15 cm. The beam slab is 95 cm high and 99 cm wide. In addition, there are ear walls and back walls.

Knowledge about expansion joints:

Expansion joint is an important part of bridge structure. The quality of expansion joint construction not only affects the beauty of the bridge deck, but also has a great influence on the overall structural safety of the bridge. Expansion joint is an important part of bridge structure. Under the influence of temperature change, concrete shrinkage, live load, settlement and creep of pier and abutment, the bridge span structure will be deformed, which will lead to the displacement of beam end. In order to adapt to this displacement and keep the vehicle running smoothly on the bridge, transverse expansion joints must be set between the two ends of the bridge deck and between the beam end and the back wall of the abutment. Once the bridge expansion joint is damaged, it will lead to vehicle jumping, noise and water leakage, which will affect traffic safety and shorten the service life of the bridge. The quality of bridge construction joints is closely related to the quality control in the construction process.

1. Bridge expansion joint types: steel plate expansion joint, filler expansion joint, geotextile expansion joint and plate rubber expansion joint.

2. Construction technology and method of bridge expansion joint

(1) Preparation before construction of bridge expansion joint. Before the construction of bridge expansion joints, a series of construction preparations are needed. For the preparation of bridge deck, at present, in order to ensure simple construction control and high quality, it is generally required that the construction of expansion joints should be carried out after the continuous paving of bridge deck black pavement is completed; For expansion joints, the quality of expansion joints must be checked before construction, and they must be loaded, unloaded, placed and transported in strict accordance with the methods required by manufacturers. Bending or twisting expansion joints cannot be used; High-quality cement and aggregate must be selected for the concrete used in the construction of bridge expansion joints. The strength of concrete is generally one grade higher than that of beams, and certain additives can be added when necessary.

(2) Construction technology and method of bridge expansion joint.

After making relevant preparations before the construction of bridge expansion joint, the construction of bridge expansion joint is divided into four steps: slotting, installation, concrete pouring and maintenance.

1). During the construction of slotted beam expansion joints, firstly, the slot width should be determined according to the requirements of construction drawings, accurately set out, cut with a cutting machine, and pay attention to protecting the pavement outside the kerf to prevent the stone powder generated during kerf from polluting the pavement.

2). Installation-When installing bridge expansion, whether the temperature at the time of installation is quite different from that at that time should be considered. If yes, the clearance value of assembly and positioning should be adjusted before installing the expansion joint.

4). Maintenance-After concrete pouring is completed, it should be covered with sacks. And spray water for maintenance. When the concrete strength reaches more than 50% of the design strength, rubber sealing strips can be installed, and they can only pass after the concrete strength reaches the design strength.

Day 4: Blue Water Garden on Lianjiang Avenue

The building is a barrel-shaped frame-shear wall structure, which is environmentally friendly. Residents take it out by themselves and there is no garbage passage. Because of the complex foundation, the sliding sheet pile structure is adopted, and the pile depth is 17m, and hundreds of high-strength steel bars are applied. Piles of buildings and bridges bear different moving loads to prevent cracks caused by uneven settlement and hysteresis. (Whether a section is a shear wall or a column depends on the aspect ratio: when the ratio is greater than 8, it is called a general shear wall. In order to ensure the ventilation of the basement, a passage leading to the top floor is set to adjust the air flow, and a vent is set at the top to prevent water from entering when it rains. Toilets and toilets generally have low floors, but there are one or more holes through which water can be discharged. The first, second and third floors are commercial facade rooms, which run through from top to bottom, and guardrails should be set around to ensure safety. The building is also designed with balconies and guardrails, which should not be less than1.2m. The windows protrude outward, so there is a "cover" on the top and bottom to keep out the rain. You can also put air conditioning here. The key to judge whether a building is a frame structure or a shear wall structure is whether there is a shear wall, and the frame structure is only composed of columns.

For high-rise buildings, high-rise frames, frame-shear wall structures, shear wall structures, frame-supported shear wall structures and tube structures are generally adopted. The following is the understanding of relevant knowledge:

1. High-rise frame: The stress system is composed of beams and columns, which bear reasonable vertical load and poor horizontal load. It is used for buildings with small height and few stories (vertical load has little influence on structural design). Because of the large height and many stories, the cross-section size of beams and columns is unreasonable. For example, the main building of the Great Wall Hotel adopts this structure.

2. Frame-shear wall structure: Shear wall is a section of reinforced concrete wall, which is called shear wall because of its strong shear resistance (which limits the flexibility of building layout to some extent). Shear walls bear most horizontal loads (about 80%), while frames mainly bear vertical loads (which can greatly reduce the cross section of columns), and are used in office buildings, hotels, houses and some craft rooms. For example, the Science and Technology Complex of Beijing University of Technology (16th floor), Vocational and Technical Teachers College of Beijing Union University (13rd floor) and the plane of Guangzhou Zhongtian Plaza Building (80th floor) all adopt this structure.

3. Shear wall structure: When the building is high and the horizontal load is large, it is appropriate to adopt shear wall structure (which is composed of shear walls arranged vertically and horizontally) to bear horizontal and vertical loads at the same time, so that the space is separated and fixed. The building layout is generally used in houses, hotels and so on. For example, Guangzhou Baiyun Pavilion (1976) has a standard floor of 1+ 33 and a height of 1 12.45 m, ranking first in China) > 100m.

4. Frame-supported shear wall structure: Due to the shortage of land, the functions of upper-level houses or office buildings are different from those of lower-level shops. Upper-level houses and offices need small bays, which are suitable for shear wall structures, while lower-level shops need large spaces, which are suitable for frame structures. The two structures are combined together, and a huge transfer beam (often near the first floor, used as the equipment floor) is set at the joint to transfer the load of the upper shear wall to the lower column. Attention should be paid to the great stiffness of the upper shear wall and the small stiffness of the lower frame in the design, which is unfavorable to the overall earthquake resistance. Transfer beam, as a connection node, has complex stress, so it should be used with caution in high seismic fortification areas.

5. Tube structure: A high-rise building system with one or more tubes as the load-bearing structure is suitable for multi-storey high-rise buildings. Under the lateral wind load, the force is similar to that of a rigid box-section cantilever beam, with the windward side in tension and the leeward side in compression. The tube structure is divided into frame-tube system (the tube with shear wall at the core and frame around it), tube-in-tube system (when the surrounding frame columns are densely arranged, it can be regarded as an outer tube and the inner core shear wall as an inner tube, forming a tube-in-tube system), truss tube system (tube structure system with diagonal bracing system, system stiffness and horizontal bearing capacity) and bundle tube system (tube structure composed of multiple tubes).

Third, the internship experience:

The four-day internship is over. Although the four-day internship is very short, it has brought us an unforgettable experience. During these four days, we learned more about roads and bridges, civil buildings, construction procedures and methods of roads and bridges, general classification of roads and bridges and related knowledge of civil buildings, and mastered some practical knowledge. The so-called practice is the only criterion for testing truth. This internship is the initial connection between what we have learned before and practice, which not only strengthens the correctness of what we have learned before, but also broadens our knowledge and contacts many useful new terms. Every new technology in this industry comes from practice, as long as we pay attention to learning everywhere.

In a word, in this internship, we have made progress in all aspects. I believe that the experience brought by this internship will definitely bring great help to our future study and life!