What are the symptoms of damage to bridge bearings?

Bridges are like the skeletal system of the human body, and supports are the "joints" that connect various "bones". As a bridge engineer with many years of experience, I have seen too many major accidents caused by bearing diseases. Today, we will take you to a deeper understanding of this often overlooked "bridge gate".

I. Pain Signals (Symptoms) of Bridge Bearings

1. Voiding Symptoms: Obvious gaps appear between the bearing and the beam/pier. Hazard: Equivalent to joint dislocation, leading to abnormal stress concentration. Case Study: A cross-river bridge experienced a 15cm misalignment of the beam due to bearing voiding.

2. Shear Deformation (Common in Rubber Bearings) Symptoms: Wavy, "layered cake"-like protrusions appear in the rubber layer. Data: When the deformation exceeds the design value by 30%, the bearing capacity decreases by 50%.

3. Steel Plate Corrosion (Fatal Flaw in Steel Bearings) Symptoms: "Rust tears" appear on the surface, and anchor bolts corrode into a honeycomb pattern. Case Study: A northern overpass experienced bearing fracture due to chloride corrosion.

4. PTFE Plate Wear (Killer of Sliding Bearings) Characteristics: "Fish scale" pattern appears on the sliding plate surface; if the thickness decreases by more than 2mm, immediate replacement is required.

II. The Truth Behind the Lesions (Cause Analysis)

1. Inherent Insufficiency and Design Defects: A cable-stayed bridge suffered from insufficient wind resistance due to incorrect bearing selection. Substandard Materials: Testing revealed that inferior rubber bearings shortened the service life by 60%.

2. Acquired Imbalance: Overloading and Heavy Impacts: A national highway bridge experienced an average of 3,000 overloaded trucks daily. Temperature Stress: In areas with a temperature difference of 50°C, bearing displacement exceeded the design value by 2.8 times. Chronic Corrosion: The salt spray corrosion rate of coastal bridges is 7-10 times that of inland bridges.

3. Lack of Maintenance and Clogged Drainage Systems: Waterlogging accelerated rubber aging. Ten Years Without Maintenance: A bridge bearing was jammed by debris, causing rotational failure.

III. A Shocking Case: A Retrospective of an Accident on a Hangzhou Elevated Bridge

2019 Inspection Revealed: 100% Corrosion of Pot Bearing Anchor Bolts

Disassembly Revealed: Rubber Sealing Rings Carbonized and Cracked

Emergency Response: Overnight Repair Using a "Lifting + Replacement" Process

IV. Prevention Strategies (Engineer Recommendations)

1. Inspection System

Mandatory Inspection Items: Annual Measurement of Bearing Displacement, Quarterly Inspection of Dust Covers

New Technology: 3D Laser Scanning + AI Defect Recognition System

2. Targeted Treatment

Temporary Measures: Stainless Steel Sheet Pads to Raise Voided Bearings

Ultimate Solution: Overall Lifting and Replacement (Accuracy Controlled to 0.1mm Level)

3. Preventive Measures

New Materials: Weathering Steel Bearings + Graphene Coating

Intelligent Bearings: Built-in Sensors for Real-Time Pressure/Displacement Monitoring

Conclusion:

Bridge bearing defects are like silent killers; every accident leaves a trace. It is hoped that this article will awaken more people's awareness of the importance of "bridge joints."