As an important component of modern transportation infrastructure, the main tower construction of long-span cable-stayed bridges constitutes a critical phase of the entire bridge project. The height and structural complexity of main towers pose great challenges to construction technology and safety. This paper introduces the key technologies for main tower construction.

1. Optimization and Innovation of Construction Technology

Optimization and innovation of construction technology for main towers of long-span cable-stayed bridges are essential to ensure smooth project execution. The new steel boxed cofferdam technology improves the anti-seepage performance and stability of cofferdams by optimizing structural design and material selection. During concrete pouring of main towers, layered pouring and vibration technology can effectively prevent cracks and honeycombing inside concrete.

The compactness and uniformity of concrete are guaranteed through precise control of the thickness of each concrete layer and vibration duration. The application of intelligent formwork technology also brings innovations to construction procedures. Equipped with sensors, intelligent formwork can monitor concrete pouring status and formwork deformation in real time. The feedback data allows timely adjustment of formwork supporting force and pouring speed, thus improving construction quality and efficiency. Combined with BIM technology, construction simulation and optimization can identify potential construction hazards in advance, such as structural collisions and unreasonable construction sequences, enabling timely revision of construction plans. Thanks to these technological optimizations and innovations, the efficiency and quality of main tower construction for long-span cable-stayed bridges have been markedly enhanced, laying a solid foundation for subsequent works.

To meet the stringent requirements of main tower construction, new large tower cranes have been developed. Featuring greater lifting height and load capacity, these cranes can satisfy the hoisting demands of large components during main tower construction. Equipped with advanced control systems, they achieve precise hoisting positioning and speed regulation, greatly boosting the efficiency and safety of lifting operations. Construction technology optimization also includes redesign of construction workflows. In conventional workflows, poor connection between working procedures often leads to schedule delays. By adopting advanced construction management concepts, workflow optimization realizes tight connection of each process, cutting waiting time and resource waste. After the completion of main tower concrete pouring, formwork removal and cleaning shall be carried out immediately to prepare for subsequent construction stages.

2. Construction Quality Control and Monitoring Technology

Construction quality control and monitoring technology are critical to guarantee the safety and quality of main tower construction for long-span cable-stayed bridges.

During steel bar binding of main towers, strict inspections are conducted on steel bar specifications, quantity and spacing to ensure the stability and accuracy of steel reinforcement frameworks. Advanced monitoring technologies are adopted for real-time construction supervision. High-precision measurement using total stations and levels enables real-time monitoring of main tower verticality and displacement. Strain gauges and displacement sensors installed at different positions of the main tower collect structural stress and deformation data continuously, which are transmitted to the monitoring system for analysis. Remedial measures can be implemented promptly once abnormal data is detected. Unmanned aerial vehicle (UAV) technology is applied for construction inspection, which can rapidly discover safety and quality defects, such as unstable formwork supports and uneven concrete pouring. The adoption of these quality control and monitoring technologies effectively safeguards the quality and safety of main tower construction, reduces construction risks, and elevates the overall project quality.

Key technologies for main tower construction of long-span cable-stayed bridges are of great significance to bridge engineering. The application of optimized and innovative construction technologies as well as quality control and monitoring methods can substantially raise construction quality and safety standards. In the future, with continuous technological advances and accumulated engineering experience, the construction technologies for main towers of long-span cable-stayed bridges will keep improving, providing stronger support for transportation infrastructure development.