- Zhongjiao Engineering Materials
- November 14, 2020
Comparative Analysis of Ddvantages and Disadvantages of Prestressed Structures on Bridge Engineering
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Prestress is widely used in highway and bridge engineering. In fact, no matter what product has its advantages and disadvantages, as long as we use the advantages of the product in the right place, it is beneficial to the overall project.
Prestressed concrete is to make the concrete subject to certain compressive stress in advance by tensioning the steel cable and then bearing the external load. It started to be used in my country around the 1950s. Due to the technical advantages and characteristics of prestressed concrete, prestressed concrete relieves the tensile stress of the concrete, so that the tensile stress of the structural part is well controlled, effectively alleviating the cracking of the concrete, and greatly improving the crack resistance of the component. The quality and span of highway bridges have been improved to a certain extent.
Analysis of the advantages and disadvantages of prestressed structures
- Advantages of prestressed structure
Prestressing technology can appropriately reduce the weight of the bridge because the application of prestressing technology requires high-quality construction materials, that is to say, the concrete used is high-viscosity, and the steel bar is high-strength. When ensuring the same construction quality, the number of materials used will be relatively small, which reduces the weight of the structure itself, and the utilization rate of steel is appropriately increased. From an economic point of view, the application of prestressing technology can reduce the cost of engineering organizations, and if it is from the perspective of engineering quality, the reduction of the structural weight can increase the carrying capacity of the entire highway bridge.
The application of prestressing technology in highway bridge construction can also adjust the internal force of the bridge structure. In other words, if the span of the bridge project is large, the application of prestressing technology can ensure the integrity of the project and improve the stability of the whole project.
- Disadvantages of prestressed structure
The prestressing technology will also bring certain shortcomings, but this shortcoming is for engineering construction, not for engineering quality. Although it can improve the construction quality of highway bridges, the prestressing technology will appropriately increase the difficulty of engineering construction, and many engineering details are difficult to control. For example, prestressing technology itself is complicated, and has high requirements on the quality of construction behavior and the equipment used in the project. Therefore, it must be equipped with experienced and skilled construction technicians and must also ensure that the mechanical equipment can meet the requirements of prestressing technology. Prestressing technology has high requirements for concrete structures. Incorrect use of concrete structures will lead to the appearance of inverted arching, which is what we often call anti-tensile stress. This anti-tensile stress will seriously affect the construction quality of highway and bridge projects. The use of prestressed structures is subject to certain conditions. Normally, prestressing technology is suitable for highway and bridge projects with a large amount of work and a large span. If it is applied to a small-scale engineering project, the project itself will have fewer components and a small span. If a large number of high-quality construction materials are used, it will greatly increase engineering investment.
Application of prestressing technology in highway bridge construction
The application of prestressing technology in highway and bridge engineering can be analyzed from three major directions, and it has applications in bending members, reinforcement construction, and reinforced concrete. The application of prestressing technology in bending components mainly relies on carbon fiber, because it has better strength and the construction difficulty is also low; usually, in the construction of highway bridges, the guarantee of the bearing capacity of the bridge is often the selection of component reinforcement or structural performance improvement. The ultimate goal of this is to increase the actual service life of the highway bridge and meet the requirements of bridge transportation. The prestressing technology is also a kind of reinforcement method that is currently widely used in reinforcement construction. The main method is to prestress the components of the bridge in advance so that there will be a certain tension zone and press area on the bridge. In this way, the force of the completely opposite nature will be generated in different areas, so that the strain force of the component itself will be reduced, and the bearing capacity of the component will increase. In the construction of large highway bridges, there will definitely be a multi-span continuous beam, the need to apply prestressing technology in this part is mainly because there is a positive and negative bending zone on the beam, and when the bending and shearing capacity of the beam cannot meet the requirements, targeted reinforcement is required. And the prestressing technology is to use high-strength carbon fiber to strengthen it to improve the bearing capacity of the bridge.
