Based on the present situation of bridge construction, the cracks in bridge construction are classified, and their causes are analyzed, so as to study the crack prevention strategies in bridge construction, so as to improve the construction efficiency and quality, promote the stable construction work and improve the aesthetics of bridge engineering.
Keywords: bridge construction; Cracks; Preventive and control measures;
With the development of national economy and the advancement of urbanization, the number of bridge projects has gradually increased. Under the guidance and influence of market economy system, bridge engineering has played a great role in promoting the development of urban economy, national economy and national comprehensive strength. With the increase of the number of bridge engineering, some problems in bridge engineering are gradually exposed. Once the bridge crack phenomenon develops to a serious degree, it will cause great safety accidents and great waste of resources.
1 Damage of cracks in bridge construction
As far as the present situation of bridge construction projects in China is concerned, bridge cracks are the most important factor affecting the quality of bridge projects. Once bridge cracks occur, it will have an immeasurable negative impact on the overall quality of bridge engineering. The harm of cracks to the quality of bridge engineering mainly includes the following aspects: First, once cracks appear in the bridge, it will seriously affect the stability of the overall engineering structure of the bridge. In the case of structural fracture or structural stability damage, it is very dangerous to use bridge engineering. Secondly, for bridge engineering, cement and other external mixed materials ensure the stability and safety of the internal steel structure of the bridge. Once cracks appear in the bridge, the steel bars inside the bridge will be exposed. Under the long-term influence of the surrounding environment, such as long-term sun exposure or rain erosion, the steel bars will be worn and corroded to varying degrees, thus causing the looseness of the internal structure of the bridge, affecting the safety and stability of the overall structure of the bridge project, shortening the service life of the bridge project and wasting certain economic resources. Thirdly, due to the occurrence of bridge cracks, the service performance and service life of bridge engineering will be shortened to varying degrees. Because the causes of bridge cracks and the surrounding environment have different damage to the internal structure, they have different effects on the service life of bridge engineering, but they will all cause certain safety risks.
2 causes of cracks in bridge engineering
As mentioned above, once cracks appear in bridge engineering, it will definitely affect the overall quality and service life of bridge engineering. In order to study the preventive measures of bridge engineering, it is necessary to discuss and classify the causes of cracks in bridge engineering, study the prevention and control of bridge engineering in a targeted manner, and improve the safety and stability of bridge engineering.
2. 1 The quality of concrete material is unqualified.
In the process of bridge engineering construction, concrete is one of the essential building materials, which has a great influence on the final quality of bridge engineering. Bridge engineering is basically wrapped by the internal structure of concrete, so if there are quality problems in concrete, it will cause cracks in the bridge to some extent. Concrete is mainly composed of cement, aggregate and some additives, so even if there are quality problems in the material composition of concrete, it will affect the overall quality of concrete, and then affect the construction quality of bridge engineering. Generally speaking, concrete is a very common building material in building engineering. Practice has proved that it has relatively stable performance and bearing capacity. Therefore, it is not difficult to understand that when there is a problem with the quality of concrete building materials, it will have a great impact on the overall construction quality of bridge engineering, and cracks are only one of the manifestations of the impact, threatening the safety and stability of bridge engineering.
2.2 cracks caused by load
Generally speaking, the load of bridge engineering is set at the initial stage of design, and the bridge engineering is built according to the bridge load requirements in the budget, but when it is actually put into use, the actual negative weight of bridge engineering is often greater. This is a problem after it is put into use. In the process of bridge construction, it is often necessary to use high-quality construction equipment and materials, which are usually placed in the place where the bridge has been built for easy call. However, if the relevant construction equipment and materials are placed in an unreasonable position in the actual construction process, or the relevant construction requirements are not observed in the installation process of the bridge structure, the actual load of the bridge structure will be greater than the theoretical load, thus causing additional pressure on the bridge project, causing bridge cracks and affecting the overall quality of the bridge construction project. In addition, in the process of bridge construction, due to the lack of technology and experience of the relevant construction personnel, the professional quality is relatively low, the internal engineering structure of the bridge engineering has changed, and the bridge engineering lacks fatigue detection, which leads to the wrong estimation of the actual bearing capacity of the bridge, which will increase the load of the bridge engineering and lead to bridge cracks. Finally, in the actual construction process of bridge engineering, the error of bridge fatigue calculation by the mechanical equipment of the construction unit will also affect the occurrence of bridge construction cracks.
2.3 Cracks caused by shrinkage
In the process of bridge construction, improper operation of several links will cause bridge cracks. The first is shrinkage. In the process of bridge construction, concrete pouring is an important construction process. After concrete pouring, it needs to meet the hardening standard. The water on its surface will evaporate rapidly in a short time, which will reduce the water in the concrete structure as a whole, but the water in the internal structure will not evaporate completely, which will lead to the difference between the water on the concrete surface and the water inside, and make the internal and external forces unbalanced. After concrete is hardened, uneven moisture will cause some shrinkage, and then cracks will occur. The second is plastic shrinkage. This shrinkage usually occurs about 5 h after concrete pouring. Due to the change of concrete moisture, molecular chains are formed, and the rapid loss of surface moisture forms plastic deformation, and cracks along the direction of steel bars will also appear. The third kind of crack is more common, which is caused by temperature difference. Under the influence of thermal expansion and cold contraction, when the temperature difference between the inside and outside of concrete is large, concrete will harden, and the rapid hardening in a short time will cause uneven shrinkage, thus forming temperature cracks. In addition, under the influence of certain environmental conditions, it will also cause temperature cracks, because the temperature of the bridge is greater than the load stress, which will break the internal structure of the bridge. In summer, uneven heating of bridge structure will also affect the quality of concrete, thus causing temperature cracks and affecting the quality of the project.
3 bridge engineering concrete crack prevention measures
3. 1 Strictly control the quality of materials
In the process of bridge construction, the quality of building materials greatly affects the final quality of the bridge. In order to ensure the construction quality of bridge engineering, it is necessary for relevant units to manage and control the construction materials. First of all, the construction unit needs to be equipped with personnel with professional knowledge to select construction materials. They need to have some experience and a certain understanding of various concrete materials. On the basis of not increasing the construction cost, high-quality building materials should be selected as far as possible, so as to avoid secondary rework and substandard construction quality caused by quality problems of building materials, and avoid cracks in bridge engineering caused by quality problems of concrete materials. At the same time, in the process of concrete pouring, attention should be paid to related technical links to avoid uneven concrete condensation or poor performance caused by improper technical operation. Before using concrete, the proportion of concrete materials must be well made, and the construction of bridge engineering should be carried out scientifically and reasonably.
3.2 Improve the load problem
For bridge engineering, reasonable load can greatly reduce the probability of cracks in bridge engineering. Therefore, it is necessary for relevant staff to improve the bridge load, improve the rationality of concrete structure design and steel bar arrangement spacing, and avoid cracks in bridge engineering due to structural problems. Admixtures can be properly added in the process of concrete pouring to improve the protective effect of concrete on internal structure. In order to avoid the influence of load problems on bridge engineering, it is necessary to limit the passage of overloaded vehicles and control the actual load of bridge engineering within a reasonable range.
4 conclusion
Cracks appear in some bridges during construction or after they are put into use for a period of time, which not only affects the stability and safety of the overall structure of the bridge, but also affects the service life of the bridge. Therefore, it is very necessary to study the causes and prevention measures of bridge cracks, which can effectively reduce the occurrence of bridge cracks, improve the stability and service life of bridge projects, ensure the travel safety of urban residents, and promote the further development of urbanization and economy.
refer to
[1] White and blue sky. On cracks in bridge construction [J]. Architectural Engineering Technology and Design, 20 14 (27) :329.
[2] Yu Chunyong. Cracks in Bridge Construction and Measures [J]. Urban Architecture, 20 15 (32) :254.
Horse, Wang. Analysis and discussion on cracks in bridge construction [J]. Real Estate Guide, 20 13 (2 1) :207.
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