January 6, 2026
Rubber Bearings vs. Steel Bearings for Municipal Bridges:
Comparison of Core Performance Indicators and Cost-Effectiveness Analysis When selecting bearing types for municipal bridges, it is necessary to consider the bridge's span, load characteristics, service environment, and maintenance requirements, focusing on four core performance indicators: load-bearing capacity, deformation, durability, and construction/maintenance. Cost-effectiveness must consider both initial cost and total life-cycle cost, not just the initial investment. The following is a detailed analysis across different dimensions:
I. Comparison of Core Performance Indicators: Matching Bearing Characteristics to Municipal Bridge Needs
The core requirements for municipal bridges are "safe load-bearing capacity + adaptability to urban environments (such as traffic interference and rain corrosion) + low maintenance." The differences in performance indicators between the two types of bearings directly determine the applicable scenarios. A specific comparison is as follows:
Performance indicators | Rubber bearings (taking plate/ pot rubber bearings as an example) | Steel bearings (taking steel hinge bearings / sliding steel bearings as examples) | Key Considerations for Municipal Bridge Selection |
1. Load-bearing capacity | - Vertical load-bearing capacity: relies on the compressive strength of the rubber elastomer (usually 10-15MPa), and has good adaptability to small and medium loads; - Horizontal load-bearing capacity: relies on the shear deformation of the rubber to transmit loads, and has a relatively weak ability to resist horizontal forces (requires the use of limit blocks). | - Vertical load-bearing capacity: relies on the compressive/bending strength of steel (Q355 steel compressive strength ≥310MPa), with strong adaptability to large loads and large spans; - Horizontal load-bearing capacity: relies on the rigid transmission of steel components, and its ability to resist horizontal braking force and wind load is better than that of rubber bearings. | Rubber bearings are selected for small and medium spans (≤30m) and conventional vehicle loads (City-A / City-B level); steel bearings are selected for large spans (>30m) and heavy loads (if truck traffic is also taken into account). |
2. Deformation adaptability | - Horizontal deformation: Achieved by rubber shear or sliding surface (PTFE plate of pot bearing), with strong adaptability to temperature deformation (horizontal displacement can reach ±50mm); - Corner deformation: The rubber elastomer can naturally adapt to the beam end corner (usually ≤0.02rad), without the need for additional construction. | - Horizontal deformation: achieved by sliding surfaces (steel-steel or steel-PTFE), with good adaptability to large displacements (up to ±100mm or more), but the rotation angle depends on hinge nodes (such as single hinge or double hinge), and the structure is more complex; - Rotation angle deformation: hinge nodes precisely control the rotation angle, but the non-hinged parts are rigid and have weak deformation adaptability. | Rubber bearings are selected for urban road bridges with multiple curves and small-radius ramp bridges (which need to frequently adapt to temperature deformation and small turning angles); steel bearings are selected for straight long-span bridges (such as municipal bridges across rivers, which require large horizontal displacement). |
3. Durability and environmental adaptability | - Disadvantages: Rubber is prone to aging (lifespan is usually 15-20 years), susceptible to high temperatures (softens easily at >60℃), oil contamination, and long-term water immersion; - Advantages: It has a certain degree of corrosion resistance (chloroprene rubber has good weather resistance), and does not require complex anti-corrosion treatment. | - Disadvantages: Steel is prone to rust (requires hot-dip galvanizing, anti-corrosion coating, etc., which is costly), and once the anti-corrosion layer is damaged, the rusting speed is fast; - Advantages: No aging problem, strong structural rigidity, and a service life of 30-50 years (provided that anti-corrosion is in place). | Rubber bearings are selected for ordinary urban areas that are rainy, humid, but not highly corrosive (such as pedestrian bridges and secondary road bridges); steel bearings with proper anti-corrosion treatment are selected for main road bridges in coastal areas (high salt spray), industrial areas (high pollution), or areas with high service life requirements (≥30 years). |
4. Installation and maintenance costs | - Installation: Lightweight (each plate support weighs only tens of kilograms), installation can be done manually with small equipment, with minimal traffic disruption (short-term closure at night is sufficient); - Maintenance: Regular inspection for aging (such as cracks and bulges) is required, and replacement is convenient after aging (replacing a single piece takes ≤1 day). | - Installation: Heavy weight (a single steel hinge support can weigh hundreds of kilograms), requires large hoisting equipment, has a long installation period (requires closure of the entire bridge deck), and has a significant impact on urban traffic; - Maintenance: The anti-corrosion layer needs to be recoated every 5-8 years, and repairs are difficult after damage (requires hoisting and replacement of steel components), resulting in high maintenance costs. | Rubber bearings are selected for urban core areas and busy traffic sections (such as main road bridges in the city center) (installation and maintenance do not block the road); steel bearings are selected for suburban areas and large-span bridges with low traffic volume (such as outer ring river bridges) (long-term maintenance frequency is low). |
5. Seismic performance | - Ordinary rubber bearings: have weak seismic resistance and are easily sheared during earthquakes; - Modified rubber bearings (such as lead-core rubber bearings ): can dissipate energy through lead core yielding and are suitable for low- to medium-intensity earthquake zones. | - Conventional steel bearings: High rigidity, easily transmit seismic forces during earthquakes, leading to pier damage; - Seismic isolation steel bearings (such as friction pendulum steel bearings ): Require additional seismic isolation structures, high cost, suitable for high-intensity earthquake zones. | Ordinary rubber bearings are selected in non-seismic zones or low-to-medium intensity zones (such as most cities in East and South my country); lead-core rubber bearings or special seismic isolation steel bearings are selected in high-intensity seismic zones (such as some cities in Southwest and Northwest China). |
II. Cost-Effectiveness Differences: Initial Cost vs. Life Cycle Cost
Cost-effectiveness cannot be judged solely by "how much it cost at the time of purchase." It must be considered in conjunction with the design life of municipal bridges (typically 15-30 years), calculating the sum of "initial cost + maintenance cost + replacement cost":
1. Initial Cost: Rubber Bearings are More Advantageous
Rubber Bearings: For small to medium spans (e.g., a 20m simply supported beam bridge), the cost of a single plate rubber bearing is approximately 200-500 yuan, with a total cost of approximately 800-2000 yuan per span (4 bearings); Pot bearings (suitable for large spans) cost approximately 1000-3000 yuan per piece, with a total cost of approximately 4000-12000 yuan per span.
Steel bearings: For small and medium span steel hinge bearings, a single piece costs approximately 800-1500 yuan, with a total cost per span of approximately 3200-6000 yuan (2-3 times that of rubber bearings of the same span); for large spans (such as 40m beam bridges), a single sliding steel bearing costs approximately 5000-15000 yuan, with a total cost per span of approximately 20,000-60,000 yuan (1.5-2 times that of pot bearings of the same span).
2. Life cycle cost: Steel bearings are more cost-effective in the long run (two prerequisites must be met). Taking a municipal bridge with a design life of 30 years as an example, the life cycle cost composition of the two types of bearings is as follows:
Cost type | Rubber bearing (plate type) | Steel support (steel hinge + anti-corrosion treatment) | in conclusion |
Initial cost | 100% (benchmark) | 200%-300% | - |
Maintenance costs | Inspection every 5 years (labor cost approximately 500 RMB/span), replacement every 15 years (support + construction cost approximately 3000 RMB/span), total maintenance + replacement cost over 30 years approximately 4000 RMB/span. | Reapply anti-corrosion coating every 8 years (materials + labor cost approximately 1000 RMB/span), no replacement required for 30 years, total maintenance cost approximately 3750 RMB/span. | The maintenance costs are similar, but the rubber bearings need to be replaced once, which adds extra traffic management costs during the replacement period (such as temporary detours and overtime fees for nighttime construction). |
Total lifecycle cost | Initial cost (1000 yuan) + 4000 yuan = 5000 yuan/span | Initial cost (3000 yuan) + 3750 yuan = 6750 yuan/span (small and medium spans); for large spans, steel bearings do not need to be replaced frequently, and the total cost exceeds that of rubber bearings (for example, for a 60m span bridge, rubber bearings need to be replaced twice, while steel bearings only need one maintenance). | - Small and medium spans (≤30m): Rubber bearings have lower overall lifespan costs (20%-30% lower than steel bearings); - Large spans (>30m) / Long lifespans (≥30 years): Steel bearings have better overall lifespan costs (15%-25% lower than rubber bearings). |
III. Summary: Scenarios where rubber bearings are preferred for municipal bridges:
Small to medium spans (≤30m), busy urban core areas, non-corrosive environments, and municipal bridges with a design life of 15-20 years (e.g., branch road bridges, pedestrian bridges, small-radius ramp bridges);
1. Scenarios where steel bearings are preferred: Large spans (>30m), heavy load requirements (e.g., accommodating trucks), highly corrosive environments (coastal/industrial areas), and municipal bridges with a design life ≥30 years (e.g., main road bridges across rivers, large-span suburban bridges);
2. Special scenarios: Lead-core rubber bearings are selected in earthquake-prone areas; pot bearings or sliding steel bearings are selected for large displacement requirements; and steel hinge bearings are selected for precise angle control. In short, the core of municipal bridge bearing selection is: "For small spans, consider initial cost; for large spans, consider long-term durability; for busy road sections, consider maintenance convenience; for harsh environments, consider corrosion resistance." A comprehensive judgment based on the specific project's technical requirements and cost budget is necessary.
Westcoast New Area, Qingdao City ,Shandong Province ,China
