Replacement Strategies for Aged PTFE Bridge Bearing Pads in Steel Bridges

Steel bridges are widely used in urban viaducts, railway bridges and long-span bridge projects due to their light weight, high strength and fast construction speed. PTFE bridge bearing pads are important force-transmitting and displacement-adjusting components of steel bridges. After long-term service, affected by cyclic load, environmental erosion and material natural aging, PTFE bearing pads will have aging problems such as surface wear, friction performance attenuation and structural compression deformation, which affect the structural coordination and safe operation of steel bridges. Scientific and reasonable replacement strategies for aged PTFE bearing pads are of great significance to extend the service life of steel bridges and ensure structural safety PTFE SHEET.

The first step of the replacement strategy for aged PTFE bearing pads in steel bridges is scientific aging detection and performance evaluation. It is necessary to regularly detect the surface wear degree, friction coefficient, structural deformation amount and compression resilience of bridge bearing pads, evaluate the residual service performance and safety redundancy of aged bearings, and distinguish minor aging, moderate aging and failure aging states. For slightly aged bearing pads with only slight surface wear and stable overall performance, regular monitoring and maintenance can be adopted without immediate replacement; for moderately aged bearings with decreased friction performance and partial deformation, targeted maintenance and repair can be carried out to delay aging failure; for severely aged and failed bearings with invalid displacement coordination and unstable force transmission, rapid replacement construction is required.

In terms of replacement construction technology, steel bridge structures have the characteristics of light self-weight, flexible structural deformation and sensitive stress change, so precise jacking and synchronous replacement construction schemes need to be adopted. During the replacement process, professional synchronous jacking equipment is used to lift the steel bridge superstructure evenly, ensure uniform structural stress, avoid local stress concentration and structural deformation caused by uneven jacking, and protect the steel bridge main structure from construction damage. The new replacement components adopt high-performance upgraded PTFE TUBE and sheet bearing pads, which have better wear resistance, aging resistance and friction stability than old conventional products.

The seasonal and environmental optimization strategy of replacement construction is also very important. PTFE bearing pad replacement of steel bridges should avoid extreme high temperature and extreme low temperature weather, and choose stable temperature seasons for construction, which is conducive to accurate adjustment of bridge displacement and uniform stress recovery. For steel bridges in coastal and industrial corrosive environments, anti-corrosion treatment and protective measures should be added after bearing replacement to improve the environmental adaptability and service life of new bearings.

After the replacement of aged PTFE bearing pads, long-term operation monitoring and regular maintenance strategies need to be established. Real-time monitoring of bridge structural displacement, stress change and bearing operating state is carried out to ensure that the new bearings work stably and coordinate with the steel bridge structure. Scientific replacement and maintenance strategies can effectively solve the structural hidden dangers caused by aging bearings of steel bridges, restore the mechanical coordination performance of bridge structures, extend the overall service life of steel bridges, and reduce the long-term operation and maintenance cost of bridge infrastructure.