In the current era of rapid development of transportation infrastructure, cantilever bridges, with their strong spanning capabilities and unique aesthetic value, have become key projects for connecting natural barriers and integrating road networks. However, the construction technology of cantilever bridges is complex. Quality defects in any construction process may lead to structural safety hazards and even threaten people's lives and property. Therefore, strictly controlling the key points of construction technology quality control has become the core task to ensure the quality and service life of cantilever bridge projects. This article will elaborate on the key aspects of quality control in the construction technology of cantilever bridges from five aspects: key points of raw material control, key points of pre - reserved hole construction, key points of concrete mix proportion design, data control, and key points of prestressing construction.

1. Key Points of Raw Material Control

During bridge construction, it is necessary to ensure that the raw materials used are effectively controlled and there are no quality problems. The selected sand, crushed stones, cement, admixtures, etc. should all be the most suitable. Generally speaking, portland cement has strong applicability, while slag, pozzolana, fly ash, etc. should not be used. When applying concrete, its strength should meet the requirements, and the elastic modulus should be ensured to be more stable, and the actual frequency should be understood through experiments. After the raw materials enter the construction site, they should be stacked in categories, and centralized management should be adopted, which can effectively reduce material losses and ensure that the service performance is not affected. When determining the aggregate gradation, it should be ensured that the gradation is the most reasonable, so as to greatly improve the strength of the concrete. When transporting the mixture, there should be no blockage. Therefore, attention should be paid to the use of coarse aggregates, and both the maximum particle size and the gradation should be well controlled.

2. Key Points of Construction of Preformed Holes

From the current situation of cantilever beam construction, corrugated pipes are usually selected for the construction of continuous beam holes. During construction, it is necessary to ensure that the position is accurate, so as to ensure that the position and direction of the prestressed steel bars will not be affected. When placing the corrugated pipes, the firmness must be effectively improved, and the joints should be smooth and tight. The positioning reinforcement mesh, reinforcement framework, etc. should be fixed in place. Pipeline reinforcement should be set in the corrugated pipes, which can greatly improve the strength of the corrugated pipes. The lap length should be controlled, and then both ends should be sealed to ensure that problems such as water seepage, grout leakage, and disconnection can be effectively avoided. When pouring the concrete, the dumping of the mixture must be carried out carefully to ensure that it will not affect the corrugated pipes. When vibrating, the vibrator should be used correctly and should not come into direct contact with the corrugated pipes. In some areas where the pipelines are relatively concentrated, even more caution is required, so as to greatly improve the operation quality.

3. Key Points of Concrete Mix Proportion Design

During the construction of cantilever bridges, attention should be paid to the concrete mix proportion, and the design work should be well completed to ensure that the pouring cycle can be shortened to a certain extent, and the early strength and elastic modulus of the concrete can be greatly increased. When the cement dosage can meet the actual needs, the water-cement ratio should be appropriately reduced. When conducting trial mixing in the laboratory, attention should be paid to the aggregates to ensure that the selection is the most reasonable. The aggregates must be kept dry. When conducting on-site mixing, since there will be a certain amount of moisture in the aggregates, accurate conversion must be ensured at this time. If you want to effectively improve the pumpability of the mixture, starting from the early strength and elastic modulus, an appropriate amount of water-reducing agent should be added, so that the workability and slump can meet the standard requirements. Regarding the slump, the conveying pipeline cannot be ignored. Multiple bends, multiple joints, and pressure losses, etc. should all be considered. In particular, the slump for upward pumping should be well controlled, so as to ensure that the backflow pressure can be controlled within a reasonable range.

4. Data Control

The main objective of numerical control is to ensure that the elevation parameters can be effectively managed and controlled. Relevant personnel must effectively carry out simulation calculations and modeling processing to ensure that the elevation parameters are the most reasonable. If there are any problems, they should be modified immediately. When modifying the data, the staff should integrate theory and practice. In addition to analyzing and calculating the deformation data, relevant tests should also be carried out, so that the parameter design can be more reasonable and the errors can be controlled within the minimum range.

5. Key Points of Prestressing Construction

The strength of the cast-in-place concrete box girder must meet the design requirements. The prestressing tensioning operation should be carried out in the established sequence, that is, first longitudinally, then transversely, and finally vertically. Regarding the tensioning of the cross-section, the established principles should be effectively implemented. First, the web plate and then the top plate, and the left and right should be symmetrical. During construction, the calibration work for jacks, oil pumps, etc. must be well done. During the tensioning operation, every link cannot be ignored. Initial tensioning, over-tensioning, load holding, etc. must all be carried out properly. The design of the tensioning tonnage cannot be ignored either. During tensioning, dual control must be effectively implemented. The tensioning end position is the main consideration, and the elongation value check is used as an auxiliary. And the quality of the anchor wire ropes should be repeatedly checked to ensure that there will be no situations such as wire breakage or wire slippage during tensioning.

To Wrap Up

The key points of quality control in the construction technology of cantilever bridges run through the entire project construction process. From the meticulous selection of raw materials, precise control of construction links, to accurate data analysis, each key point is crucial for ensuring the quality of the bridge. Only by implementing these key points into every construction detail can we create safe, reliable, and high - performance cantilever bridges, lay a solid foundation for the long - term development of the transportation industry, and enable the bridges to continuously play an important role over time.