▶ Core Product Characteristics

Rubber bearings achieve a dual adaptation to structural stress and deformation through the complementary combination of the high elasticity of rubber and the rigidity of metal components. The core characteristics applicable to all types are as follows:

1. High Vertical Load Capacity and Elastic Force Transmission: The composite of rubber and steel plate forms a rigid elastic body with high vertical compressive strength, uniformly transmitting the load from the superstructure to the foundation. Furthermore, the elasticity of the rubber buffers load impact, reducing structural vibration.

2. Adaptability to Multi-directional Deformation: It can freely accommodate vertical compression, horizontal displacement, and angular deformation, meeting the deformation requirements of bridges/buildings caused by temperature expansion and contraction, concrete creep, and foundation settlement, without stress concentration.

3. Excellent Seismic Isolation and Damping Performance: The viscoelasticity of rubber absorbs seismic energy and reduces vibration transmission. Neoprene/natural rubber bearings effectively protect structures in low- to medium-intensity earthquakes, and when combined with seismic-resistant accessories, they can be used in high-intensity earthquake zones.

4. Weather-resistant and durable: Utilizing an aging-resistant rubber formula with added antioxidants and reinforcing agents, it maintains stable performance within a temperature range of -40℃ to 60℃. It is resistant to rainwater, groundwater, and weak acids and alkalis, with an outdoor service life of ≥20 years (bridge bearings) / ≥30 years (building bearings).

5. Easy installation and low maintenance costs: Standardized production results in lightweight and compact products that require no welding on-site; installation simply requires positioning and fixing. Under normal use, there are no easily damaged parts, requiring only periodic inspections and not frequent replacements.

6. Good structural compatibility: Elastic deformation without rigid friction prevents additional stress on piers and foundations. The PTFE sliding plate bearing also reduces horizontal displacement resistance, allowing for free structural sliding.

▶ Mainstream Product Types, Specifications, and Applicable Scenarios

Rubber bearings are classified into three main categories based on structural form, load-bearing capacity, and functional characteristics: plate rubber bearings (including PTFE sliding plate type), pot rubber bearings, and spherical steel bearings. Each category is suitable for projects with different spans, loads, and seismic requirements, and represents over 95% of applications in the market. Specific parameters and compatibility are as follows:

(I) Plate Rubber Bearing (Basic Type, Widest Application)

Core Features

Made of multiple layers of natural rubber/chloroprene rubber bonded to thin steel plates through high-temperature vulcanization. It features a simple structure, economical cost, and convenient installation. Available in standard plate type and PTFE sliding plate type. The PTFE sliding plate type has a built-in PTFE plate, achieving low-friction horizontal displacement.

Standard Specifications

1. Type Classification: GYZ (circular), GJZ (rectangular); GYZF4 (circular PTFE sliding plate), GJZF4 (rectangular PTFE sliding plate)

2. Dimensions: Circular diameter Φ100~Φ600mm, Rectangular 100×100~600×800mm; Total rubber layer thickness 21~110mm, Number of steel layers 3~15

3. Load Capacity Rating: Vertical load capacity 100kN~10000kN (customized according to project requirements, standard 2000kN~5000kN)

4. Displacement Capacity: Standard type horizontal displacement ≤ 10% of total support thickness; PTFE sliding plate type horizontal displacement ≤ 150mm (sliding plate limiting device can be equipped)

▶ Core Applicable Scenarios

For small to medium span projects, priority is given to scenarios with moderate vertical loads and small horizontal displacements:

Bridge Engineering: Highway/municipal small bridges, ramp bridges, pedestrian bridges with spans ≤20m, and simply supported beam supports for beam-slab bridges;

Building Engineering: Beam-slab supports for multi-story civil buildings and light industrial buildings, and steel structure roof supports;

Municipal Engineering: Lightweight structures such as small utility tunnels, pedestrian overpasses, and bus stops.

▶ Core Advantages of Rubber Bearings

Compared to traditional steel and concrete bearings, rubber bearings, with their "rigid-flexible combination" structural characteristics, offer comprehensive performance advantages and are the preferred bearing type in engineering design:

1. Uniform Stress Distribution, Protecting the Foundation: Elastic force transmission disperses concentrated loads on the superstructure, preventing localized crushing of piers and foundations, and reducing structural design complexity.

2. No Rigid Friction, Reduced Wear: The elastic deformation of rubber or the sliding of the PTFE plate involves flexible contact, eliminating rigid friction between metals and preventing wear debris, thus extending the service life of both the structure and the bearing itself.

3. Self-Adaptive Deformation, No Manual Adjustment Required: Automatically adjusts displacement and rotation according to structural deformation, eliminating the need for manual adjustment devices and adapting to deformation needs throughout the entire lifecycle of the project.

4. Vibration and Noise Reduction, Enhanced User Experience: The viscoelastic properties of rubber absorb vibrations and noise generated by vehicle traffic and equipment operation, resulting in greater comfort during bridge operation and building use.

5. Standardized Production, High Interchangeability: Designed and manufactured according to national standards, bearings of the same model have consistent dimensions and performance, eliminating the need for redesign during later maintenance and replacement; direct replacement is sufficient. 6. Lightweight and easy to install: Under the same load-bearing capacity, the weight is only 1/3 to 1/2 of that of steel bearings. Bridge piers and building foundations do not require additional reinforcement. On-site hoisting and positioning are convenient, shortening the construction period.

▶ Key Construction and Installation Points

The installation quality of rubber bearings directly affects their performance and lifespan. The core principles are **"flatness, alignment, fixation, and protection"**. The general construction points for all three types of bearings are as follows:

1. Base Treatment: Clean the top surface of bridge piers and building foundations of laitance, dust, and oil stains to ensure a flat, firm surface with a levelness deviation ≤1‰. If the surface is uneven, level it with cement mortar or epoxy mortar.

2. Bearing Positioning: Accurately lay out the lines according to the design drawings, ensuring that the center of the bearing coincides with the stress center of the superstructure and foundation. The sliding direction of bidirectional/unidirectional movable bearings must be consistent with the direction of structural displacement; they must not be installed in reverse.

3. Bearing Installation:

1. Plate Bearings: Placed directly on the leveling layer. When the upper structure beams are lowered, press them together slowly to ensure even stress distribution, preventing uneven pressure or suspension.

2. Limiting and Protection: Large displacement bearings require limit blocks installed according to the design to prevent damage from excessive displacement. After installation, install protective railings around the bearings to avoid impacts from heavy objects during construction and to prevent mortar from entering the sliding surface during concrete pouring.

3. Post-Inspection: After project completion, regularly inspect the bearings for deformation, displacement, and sealing. For PTFE sliding plate bearings, replenish with silicone grease lubricant every 1-2 years. Repair or replace any bearings with cracked rubber or rusted steel plates promptly.

Implementation Standards

JT/T 4-2019

Production workshop