In our previous article, Key Technologies and Practices in Foundation Construction of High-Speed Railway Bridges, we reviewed the three basic foundation types—pile foundations, open caisson foundations and spread foundations—and the key technical points involved: hole forming, reinforcement cage fabrication, concrete pouring and curing, caisson sinking correction and base sealing, and foundation pit support and base treatment. That article established the quality logic of foundation work: highly concealed, and therefore controlled at the source. Above the foundation lies the pier and abutment—the hub that carries vertical loads and transfers transverse forces. Its dimensional accuracy, concrete density, prestressing effectiveness and appearance quality directly affect the load-bearing behavior of the superstructure and the smoothness of train operation. This article focuses on pier and abutment construction, covering formwork design and installation, concrete pouring and curing, prestressing, appearance quality control, and the transition zone between abutment and subgrade.

1 Pier Construction Technology and Practice

Pier formwork design and installation must take into account the pier's structural form and construction loads. Materials with suitable strength and stiffness should be selected, surface flatness and joint precision controlled during fabrication, and axis and elevation precisely set during installation. Joints must be tight and firm to prevent grout leakage and deformation during pouring, and a full inspection should be carried out after installation to ensure compliance with construction requirements. Pier concrete pouring requires controlled discharge speed and uniformity, with layered pouring adopted. Vibration frequency and depth must be regulated to ensure concrete density, while workability should be monitored and the operating rhythm adjusted promptly to avoid segregation, honeycombing, surface voids and other defects. Pier prestressing requires rational layout of prestressing tendons, precise control of cutting length and installation position, and flat, undamaged placement. During tensioning, stress values and loading rates must be controlled, and the timing scheduled in line with concrete strength development to ensure prestressing effectiveness and the pier's load-bearing performance. Appearance quality control should start from every construction stage: optimizing formwork jointing to reduce seam marks, controlling concrete pouring to avoid surface defects, and carrying out timely surface finishing and curing after pouring to improve flatness and smoothness and ensure the pier meets appearance quality standards.

2. Abutment Construction Technology and Practice

Abutment formwork must be designed and fabricated specifically for the abutment's structural form and dimensions. Material selection should balance strength and cost-effectiveness, and fabrication precision must meet specification requirements. The construction sequence should follow formwork installation, positioning, fixing and inspection. During installation, attention must be paid to the interface between formwork and foundation and between formwork panels, ensuring accurate positioning and firm fixing to prevent displacement during construction. Abutment concrete pouring and curing should account for the abutment's load-bearing characteristics: pouring sequence should be rationally arranged, and pouring speed and vibration quality controlled to ensure uniform, dense concrete. Curing must begin promptly after pouring, with methods selected according to ambient temperature and humidity; curing time and moisture conditions should be controlled to prevent shrinkage cracks on the concrete surface and ensure the abutment's structural strength and durability. The connection between abutment and subgrade must follow the technical requirements for the transition zone between high-speed railway bridges and subgrade. A rational transition structure should be provided, and the connection area compacted in layers with controlled layer thickness and passes to ensure specified density. Elevation and slope control at the connection must be strengthened during construction to ensure a smooth abutment–subgrade transition, reduce differential settlement, and avoid structural defects caused by improper connection, thereby safeguarding the ride comfort and safety of high-speed railway operations.

Pier construction has four control priorities: formwork precision, concrete density, prestressing timing and appearance quality. Abutment construction, beyond tailored formwork design and concrete pouring and curing, places greater emphasis on the transition zone with the subgrade—layered compaction, elevation and slope control, and prevention of differential settlement are all key to ride comfort. Positioned between foundation and girder, the pier and abutment carry girder loads from above and transfer foundation reactions below. Their construction quality is constrained by foundation accuracy and directly affects the alignment accuracy and geometric control of subsequent girder erection—making them a vital link in the bridge construction chain.

Above the pier and abutment lies the direct load-bearing element of the bridge—the girder. Our next article will introduce Key Technologies and Practices in Girder Construction of High-Speed Railway Bridges.