The previous article has conducted a detailed discussion on the basic principles, construction characteristics, application scope and common problems of prestressed technology in bridge construction, clarifying the core value of this technology in improving the safety, durability and economy of bridge structures. In modern bridge engineering, prestressed technology has been widely applied due to its unique advantages such as improving structural bearing capacity, enhancing structural stability and prolonging service life.

1. Selection and Application of Prestressed Steel Strands

As an important component of prestressed technology, the selection and application of prestressed steel strands are directly related to the effectiveness of prestressing. Prestressed steel strands are steel products twisted from multiple steel wires, featuring high strength and low relaxation. According to different surface treatment methods, prestressed steel strands can be divided into uncoated, galvanized and other types. Uncoated low-relaxation prestressed bridge steel strands are widely used in bridge engineering due to their excellent mechanical properties and corrosion resistance. When selecting prestressed steel strands, factors such as the actual needs of the bridge project, construction conditions and material properties need to be considered. Firstly, it is necessary to ensure that the strength of the steel strands meets the design requirements to guarantee the bearing capacity of the bridge. Secondly, the relaxation performance of the steel strands should be taken into account to avoid excessive prestress loss caused by relaxation during use. In addition, the corrosion resistance of the steel strands needs to be considered to ensure their durability in complex environments. Prestressed steel strands are mainly used in the tensile zones of bridges, such as prestressed concrete beams and prestressed concrete slabs. By tensioning the steel strands, pre-compressive stress can be generated inside the concrete, thereby offsetting the tensile stress caused by external loads and improving the structural bearing capacity. Prestressed steel strands can also be used in bridge reinforcement projects; increasing the number of prestressed steel strands or raising the tensioning stress can enhance the bearing capacity and stability of the bridge.

2. Selection and Application of Prestressed Anchors

Prestressed anchors are important components in prestressed concrete structures, used to fix and transmit the tensioning force of prestressed tendons. According to different structures and uses, prestressed anchors can be divided into wedge-type anchors, cone-plug anchors, bonded anchors and other types. Wedge-type anchors clamp the prestressed tendons through wedges and transmit the tensioning force by virtue of friction; cone-plug anchors achieve anchorage through the taper fit between the cone plug and the prestressed tendons; bonded anchors transmit the tensioning force by setting special bonding materials between the prestressed tendons and concrete to form strong bonding force. When selecting prestressed anchors, factors such as structural requirements, construction conditions and material properties need to be considered. Firstly, it is necessary to ensure that the bearing capacity of the anchors meets the design requirements to guarantee the safety of the bridge. Secondly, the construction convenience of the anchors should be taken into account to avoid affecting the construction progress and quality due to improper installation of anchors during construction. In addition, the durability of the anchors needs to be considered to ensure that they will not fail due to corrosion or wear during long-term use. Prestressed anchors are mainly used in prestressed concrete structures of bridges, such as prestressed concrete beams and prestressed concrete slabs. The prestressed tendons are fixed in the concrete through anchors and the tensioning force is transmitted to achieve the prestressing effect. Prestressed anchors also play an important role in bridge reinforcement projects; increasing the number of anchors or raising the tensioning stress can enhance the bearing capacity and stability of the bridge.

3. Analysis and Calculation of Prestress Effect

The analysis and calculation of prestress effect are key links in prestressed technology, directly related to the effectiveness of prestressing and the safety of the bridge. The analysis of prestress effect mainly includes the calculation of prestress loss, the stress distribution of prestressed tendons and the impact of prestress on structural performance. Prestress loss mainly includes anchor deformation loss, prestressed tendon relaxation loss, concrete shrinkage and creep loss, etc. When calculating prestress loss, the influence of various factors such as material properties, construction conditions and environmental conditions needs to be considered. The stress distribution of prestressed tendons is one of the important contents of prestress effect analysis; it is necessary to ensure that the stress distribution of prestressed tendons in concrete is uniform to avoid excessive stress concentration. The calculation of prestress effect mainly includes the calculation of the tensioning force of prestressed tendons, the stress calculation of prestressed concrete and the bearing capacity calculation of the structure. When calculating the tensioning force of prestressed tendons, factors such as the friction coefficient of anchors, the elastic modulus of prestressed tendons and the tensioning process need to be considered. When calculating the stress of prestressed concrete, factors such as the elastic modulus of concrete, Poisson's ratio and the stress distribution of prestressed tendons need to be considered. When calculating the bearing capacity of the structure, factors such as the geometric dimensions of the structure, material properties and prestress effect need to be considered. The calculation methods of prestress effect mainly include theoretical calculation methods and experimental verification methods. Theoretical calculation methods mainly establish mathematical models and formulas to accurately calculate the prestress effect. Experimental verification methods verify the accuracy and reliability of theoretical calculation results through actual tests. In practical engineering, a combination of theoretical calculation and experimental verification is usually adopted to ensure the accuracy and reliability of the calculation results of prestress effect.

4. Prestressed Construction of Reinforced Concrete Structures

The prestressed construction of reinforced concrete structures is one of the important applications of prestressed technology in bridge engineering. Adequate preparation work needs to be done before carrying out prestressed construction. Firstly, the prestressed tendons need to be cleaned and treated to ensure that their surfaces are free of impurities such as oil stains and rust. Secondly, the anchors need to be inspected and accepted to ensure that their quality meets the design requirements. In addition, the quality inspection and performance testing of concrete need to be carried out to ensure that its performance meets the design requirements. The technological process of prestressed construction mainly includes the tensioning of prestressed tendons, the installation and fixation of anchors, the pouring and curing of concrete and other steps. During the tensioning of prestressed tendons, the tensioning force needs to be controlled and adjusted in accordance with the design requirements to ensure uniform stress distribution of the prestressed tendons. During the installation and fixation of anchors, it is necessary to ensure that the anchors are accurately positioned and firmly fixed. During the pouring and curing of concrete, the pouring speed and vibration intensity of concrete need to be controlled to avoid damage to the prestressed tendons and anchors. Quality control of prestressed construction is a key link to ensure the effectiveness of prestressing; during construction, it is necessary to strictly control and inspect the tensioning force of prestressed tendons, the installation quality of anchors and the pouring quality of concrete. It is also necessary to conduct real-time monitoring and evaluation of the prestress effect to ensure that it meets the design requirements.

5. Prestressed Construction of Concrete Pavements

The prestressed construction of concrete pavements is one of the extended applications of prestressed technology in road engineering. Prestressed concrete pavements have the characteristics of high strength, high stiffness and good durability. By applying prestress, the bearing capacity and crack resistance of the pavement can be significantly improved, and the service life can be prolonged. The construction process of prestressed concrete pavements mainly includes the arrangement and tensioning of prestressed tendons, the pouring and vibration of concrete, the maintenance and detection of pavements and other steps. During the arrangement and tensioning of prestressed tendons, it is necessary to ensure that the prestressed tendons are accurately positioned and the tensioning stress is uniform. During the pouring and vibration of concrete, the pouring speed and vibration intensity of concrete need to be controlled to avoid damage to the prestressed tendons. During the maintenance and detection of pavements, regular inspection and maintenance of the pavement need to be carried out to ensure that its performance meets the design requirements. Quality control of prestressed concrete pavements is a key link to ensure the performance of the pavement; during construction, it is necessary to strictly control and inspect the arrangement and tensioning quality of prestressed tendons, the pouring quality of concrete and the maintenance quality of pavements. At the same time, it is also necessary to conduct real-time monitoring and evaluation of the bearing capacity and crack resistance of the pavement to ensure that the pavement performance meets the design requirements.

In summary, the specific application of prestressed technology is a systematic project involving multiple key links such as material selection, component matching, effect calculation and process implementation. The scientific control of each link plays a decisive role in the bearing capacity, stability and durability of the bridge structure. By rationally selecting prestressed steel strands and anchors, accurately calculating the prestress effect and standardizing the construction processes of various types of structures, the engineering value of prestressed technology can be maximized, laying a solid foundation for the high-quality construction of bridge engineering. However, quality control during the construction process is equally important, serving as a core guarantee to avoid deviations in technology application and prevent engineering hidden dangers. Therefore, the next article will focus on the quality control measures during the application of prestressed technology in road and bridge construction.