Thermoplastic Composite Bar Reinforced Concrete Prefabricated Longitudinal Beams

Release time: 2025/12/23 Publisher： original Views：

The reinforced concrete longitudinal beams used at the wharf are exposed to the marine environments for a long time, which can easily cause internal steel corrosion. By replacing the steel bars with high toughness, high durability, and reusable thermoplastic composite bars, the durability of concrete structures in harsh marine environments can be significantly improved. The achievements obtained by Harbin Institute of Technology in NEXCEL 2024SFP-4 Project, titled “Research and Demonstration of Thermoplastic FRP Stirrups”, have been successfully applied in the Dayangshan offshore base project. This marked the first application of thermoplastic composite in concrete prefabricated longitudinal beams, significantly improving the durability of concrete structures and achieving good demonstration effects.

Dayangshan offshore base project is located in the Yangshan Port Area of Ningbo Zhoushan Port (Figure 1).

Figure 1. Location of Dayangshan offshore base project

Dayangshan offshore base project has a shipping wharf and a material wharf, and the total length of wharf shoreline is 315 meters. The material wharf mainly composed of three parts: wharf platform, approach bridge, and air compression station platform (Figure2). The wharf platform and approach bridge adopted a high-pile beam slab structure, and the air compression station platform adopted a high-pile pier structure.

Figure 2. Floor plan of material wharf

In the design of prefabricated high-pile longitudinal beams, the thermoplastic composite bars with a diameter of 16mm were used. Each concrete beam was equipped with 6 thermoplastic composite bars, and each bar was 6 meters long. The total usage of thermoplastic composite bars was 1080 meters (Figure 3). This project was implemented in May 2024 and completed in August 2025.

Figure 3. Application of thermoplastic composite bars in prefabricated longitudinal beam demonstration project for wharf.

The successful application of high-performance thermoplastic composite bar reinforced concrete prefabricated longitudinal beams in the offshore base project not only opened up a new technological path for solving the durability problem of concrete structures at the wharf, but also effectively promoted the development of marine engineering towards longer service life and higher performance.