Detailed Explanation of Application Scenarios, Advantages and Disadvantages of Elastomeric Bearings
I. Core Types and Application Scenarios of Elastomeric Bearings
Elastomeric bearings, with polymer elastic materials at their core, can be divided into three major categories based on structural form and function, and their application scenarios are as follows:
1. Plain Plate Elastomeric Bearings
Structural Characteristics: Formed by vulcanizing and bonding single or multiple layers of rubber sheets with thin steel plates (reinforcement layers), achieving displacement and rotation through the elastic deformation of rubber.
Application Scenarios:
Medium and small-span bridges: Such as urban road bridges and rural highway bridges (span usually ≤30m), with vehicle live loads as the main load and small displacement requirements (horizontal displacement ≤5mm, rotation angle ≤0.02rad).
Low-grade highways and non-motor vehicle lanes: Scenarios with low requirements for bearing capacity (usually ≤1000kN) and controlled maintenance costs.
Simple beam bridges and culverts: Such as hollow slab bridges and simply supported beam bridges, with simple structural forms and no need for complex sliding functions.
2. Polytetrafluoroethylene (PTFE) Sliding Plate Elastomeric Bearings
Structural Characteristics: A PTFE plate is pasted on the top surface of a plain plate elastomeric bearing to form a sliding pair with a stainless steel plate at the bottom of the beam, combining rubber elasticity with low-friction sliding performance.
Application Scenarios:
Long-span bridges: Such as pre-stressed concrete continuous beam bridges (span 30-80m), which need to adapt to large longitudinal displacements (up to 50-100mm) caused by temperature changes.
Areas with significant temperature differences: Such as cold northern or hot southern regions, where bridges have large thermal expansion and contraction displacements and need sliding functions to release stress.
Bridges requiring multi-directional movement: Such as curved bridges and skew bridges, which need to meet both longitudinal displacement and small transverse rotation requirements.
3. Pot Elastomeric Bearings
Structural Characteristics: The rubber block is sealed in a metal pot, using the principle of triaxial compression to bear high loads, often equipped with PTFE sliding components, and divided into fixed type, unidirectional activity type and multi-directional activity type.
Application Scenarios:
Large bridges and heavy traffic: Such as expressway bridges and railway bridges (especially mixed passenger and freight railways), with a bearing capacity of more than 5000kN, even exceeding 100,000 tons.
River-crossing and sea-crossing bridges: Such as continuous rigid frame bridges and V-shaped pier bridges, which need to bear huge vertical loads and complex horizontal forces (wind force, seismic force) at the same time.
Structures requiring three-dimensional displacement control: Such as auxiliary piers of cable-stayed bridges and intermediate piers of continuous beam bridges, which need to adapt to the deformation of the main girder through the sliding and rotation of pot bearings.
II. Significant Advantages of Elastomeric Bearings
| Advantage Category | Specific Performance | Engineering Value |
| Excellent mechanical properties | – Strong elastic deformation ability, can adapt to small bridge rotation (rotation angle ≤0.05rad) and small displacement (≤10mm); – Non-linear elastic characteristics can buffer the impact of vehicle loads and reduce structural vibration. | Reduce stress concentration of bridge girders and piers, extend structural life, and improve driving comfort. |
| Simple structure and easy installation | – Plate bearings can be directly placed between the beam bottom and the padstone without complex connectors; – Pot bearings have a modular design for convenient on-site assembly. | Shorten the construction period, reduce installation costs, and be suitable for the rapid construction of prefabricated bridges. |
| High cost performance | – Material cost is lower than steel bearings or spherical bearings, and maintenance cost is low (plain elastomeric bearings do not require regular maintenance); – Service life can reach 20-30 years (under reasonable design). | Suitable for medium and small project budget control, especially economical in large-scale municipal bridges. |
| Strong adaptability | – Good weather resistance (natural rubber is suitable for -25℃~+60℃, neoprene can resist -40℃); – Have certain resistance to corrosive environments (such as acid rain, salt spray) (better than unprotected steel bearings). | Suitable for a variety of climate zones and environmental conditions, such as coastal bridges and industrial pollution area bridges. |
| Good shock absorption and energy dissipation effect | – The viscoelasticity of rubber can absorb seismic energy and reduce the seismic response of bridges; – Good buffering effect on low-frequency vibrations (such as vehicle driving). | Improve the seismic performance of bridges and reduce the damage of earthquakes or heavy vehicles to structures. |
III. Main Disadvantages and Limitations of Elastomeric Bearings
| Disadvantage Category | Specific Performance | Engineering Impact |
| Limited bearing capacity | – The bearing capacity of plain plate bearings is usually ≤1000kN. Although pot bearings can reach 10,000 tons, they still lag behind steel bearings (such as hinge bearings). | Not suitable for super-large bridges (such as main tower bearings of suspension bridges with a span >100m) or special heavy-haul railway bridges. |
| Easy to decay in long-term performance | – Rubber aging (oxidation, thermo-oxidation) leads to a decrease in elasticity, and life is greatly affected by the environment (high temperature and ultraviolet rays accelerate aging); – Rubber cracking and steel plate corrosion may occur under repeated loads. | Regular inspection and replacement are required (especially plate bearings usually need to be replaced in 15-20 years), and maintenance costs increase with service life. |
| Poor adaptability to large displacements | – The horizontal displacement of plain plate bearings is ≤10mm, and the displacement of PTFE sliding plate bearings is ≤100mm. If the range is exceeded, multi-joint arrangement or other bearings need to be used. | Not suitable for areas with extremely large temperature differences (such as temperature difference >80℃) or ultra-long bridges (such as span >500m). |
| Insufficient corrosion resistance | – Easy to cause chemical corrosion when encountering strong acids and alkalis (such as chemical plant wastewater, de-icing salt), and rubber swells or hardens; – Salt spray environment in coastal areas may accelerate rubber aging and steel plate corrosion. | Additional anti-corrosion measures (such as stainless steel cladding, anti-corrosion coating) are required, which increases costs and improves maintenance difficulty. |
| Poor fire resistance | – Rubber has a low ignition point (about 300℃), and is easy to melt and fail in case of fire, leading to hidden dangers in bridge structure safety. | Not suitable for fire-prone scenarios (such as bridges near chemical plants), and need to be equipped with fire protection devices. |
IV. Optimization Measures in Engineering Applications
Aiming at aging problems: Use aging-resistant rubber (such as EPDM), or add protective covers (such as stainless steel casings) to the surface of the bearing to isolate ultraviolet rays and corrosive media.
Aiming at large displacement requirements: Adopt a combination of multi-joint PTFE sliding plate bearings, or use them with other bearings (such as spherical bearings) to expand the displacement capacity.
Aiming at insufficient bearing capacity: For heavy-duty bridges, high-damping rubber can be selected or the thickness of the metal pot of the pot bearing can be increased to improve the compressive performance.
V. Summary
With excellent elasticity, economy and easy installation, elastomeric bearings have become the first choice for medium and small span bridges, especially widely used in highway engineering. However, due to the limitations of its bearing capacity, displacement capacity and durability, it needs to be used in conjunction with other types of bearings (such as steel bearings, spherical bearings) in super-large, special environment or heavy-duty bridges. In the future, with the development of nano-material modified rubber and intelligent monitoring technology (such as built-in sensors to monitor the aging degree), the performance of elastomeric bearings will be further improved, and the application scenarios will continue to expand.
Enhance load-bearing capacity with elastomeric bearings – high-performance rubber solutions. Multi-layer design ensures optimal seismic damping, vibration absorption, and all-weather durability. Fast install, ISO-certified. Trusted elastomeric bearings for resilient infrastructure worldwide.
