The expansion of the railway network and the increase in operation and maintenance intensity have rendered the durability, applicability and standardization of bridge guardrails key bottlenecks for ensuring personnel safety, improving the efficiency of maintenance windows, reducing the full life cycle cost, and promoting the high-quality development of railways. It is urgent to systematically sort out the domestic technological evolution, quantitatively evaluate the material performance, establish a full life cycle management framework, fill the gaps in the current standards regarding material selection, manufacturing and acceptance, and provide a scientific basis for the formulation of new standards.

(1) Literature and case study research - summarize the application characteristics and failure modes of steel, concrete, and fiber composite materials. (2) Material and process testing - measure the mechanical, corrosion resistance, and aging resistance properties of polyurethane pultruded composite materials. (3) Structural calculation - check the displacement of each railing post and handrail, and verify the safety margin. (4) Standard comparison - identify the gaps between domestic and international standards and the improvement paths.

Polyurethane railings are lightweight, high-strength, weather-resistant, maintenance-free, have minimal deformation and are suitable for coastal and cold regions. Steel railings corrode rapidly, are costly to repaint, and are difficult to maintain. Concrete is prone to cracking, frost peeling and rust expansion, and has a short lifespan. The current standards lack durability indicators, process control and full-life cycle evaluation, which restricts the promotion of new materials.

Establish polyurethane as the preferred option in complex environments; offer optimization directions for steel and concrete anti-corrosion structures; supplement durability indicators, process key points and cost models, and promote the standardization, lightweighting and long service life of ancillary facilities.