March 8, 2026
Bridge bearing replacement is one of the most technically demanding maintenance operations in the bridge engineering lifecycle. Bearings are critical structural components that transfer all loads from the bridge superstructure to the substructure, and their deterioration — through corrosion, PTFE wear, rubber degradation, or seismic damage — can compromise the safety and serviceability of the entire structure. This guide provides a comprehensive, step-by-step overview of the bearing replacement process using synchronous hydraulic jacking, the industry-standard technique for this operation.
Why Bridge Bearing Replacement is Necessary
Bridge bearings have a finite service life. Elastomeric bearings may develop surface cracking, delamination, or excessive shear deformation after 30–50 years of service. Pot bearings can suffer PTFE wear, contamination of the sliding surface, or corrosion of the steel components. In seismic regions, bearings may be damaged or displaced during an earthquake event. In all these cases, timely replacement is essential to restore the bridge to its design performance level and avoid more costly structural interventions.
A synchronous hydraulic jacking system in operation during bridge bearing replacement. Multiple flat jacks are positioned at bearing locations, connected to a central control unit that ensures equal lift at all points simultaneously.
Phase 1: Pre-Replacement Structural Assessment
Before any jacking operation begins, a thorough structural assessment must be carried out. This involves reviewing the original bridge design drawings to determine the bearing reaction forces, the structural sensitivity of the superstructure to differential settlement, and the locations of any utilities or services that may be affected by the jacking operation.
A site survey should confirm the condition of the pier caps and abutment bearing shelves, as these will serve as the jacking platforms. Any cracking, spalling, or reinforcement corrosion in these areas must be repaired before jacking commences. The survey should also identify any secondary structural effects of the lift, such as changes in deck drainage falls or the behaviour of adjacent expansion joints.
Phase 2: Temporary Works Design for Bridge Jacking
The jacking operation requires a detailed temporary works design, typically prepared by a chartered structural engineer. This design specifies the jack positions, the required lift height (typically only 5–10 mm above the existing bearing seating), the maximum permissible differential settlement between jack points, and the monitoring instrumentation required.
For a typical two-girder bridge, a minimum of four jacks will be required — one at each corner of the bearing arrangement. For wider bridges or continuous structures, the number of jacks and the complexity of the synchronisation requirement increases significantly.
Phase 3: Synchronous Hydraulic Jacking Equipment
Synchronous hydraulic jacking systems are the preferred equipment for bridge bearing replacement because they allow all jacks to be raised simultaneously at the same rate, preventing differential movement that could damage the superstructure or the substructure. A modern synchronous system consists of:
●Flat hydraulic jacks (pancake jacks) with a low profile to fit within the limited clearance between the girder soffit and the pier cap
●A central hydraulic power unit (HPU) that distributes hydraulic pressure equally to all jacks
●Electronic load and displacement monitoring at each jack point, with automatic shut-off if any jack deviates beyond a pre-set tolerance
●A control console allowing the operator to monitor all jack readings simultaneously
A deteriorated pot bearing showing worn PTFE surface and rust staining (left) alongside a new Bridgent replacement bearing (right). Timely replacement prevents progressive structural damage to the pier cap and girder.
Phase 4: The Bearing Replacement Procedure
With all jacks in position and the monitoring system active, the lift can commence. The procedure follows a strict sequence:
Step 1 — Pre-load all jacks to approximately 10% of the calculated bearing reaction to confirm stable contact and correct load distribution. Step 2 — Raise all jacks simultaneously at a controlled rate (typically 0.5–1.0 mm per minute) until the superstructure is lifted clear of the existing bearings by approximately 5 mm. Step 3 — Insert temporary packs to support the superstructure independently of the jacks. Step 4 — Remove the old bearings, breaking out any mortar bedding and cutting any anchor bolts. Step 5 — Prepare the bearing seating: clean, level, and repair the concrete bearing shelf to the required surface tolerance. Step 6 — Install the new bearings in their correct position and orientation. Step 7 — Lower the superstructure onto the new bearings, monitoring loads at all jack points throughout. Step 8 — Remove all temporary works and restore the bearing area to its finished condition.
Safety and Quality Assurance
Throughout the jacking operation, the bridge must remain open to traffic only if the temporary works design specifically permits this and appropriate traffic management is in place. Continuous monitoring of jack loads and displacements is mandatory. A pre-agreed "stop" criterion must be established — typically a differential settlement of more than 2 mm between any two jack points — at which the operation is immediately halted and the situation assessed.
Bridgent provides complete hydraulic jacking packages for bearing replacement projects, including flat jacks from 50 kN to 5,000 kN capacity, synchronous control systems, technical supervision, and post-replacement inspection reporting. Our equipment has been used on highway bridges, railway viaducts, and major infrastructure projects across more than 30 countries.
Planning a Bridge Bearing Replacement?
Bridgent supplies hydraulic jacking systems and provides technical support for bearing replacement operations on all bridge types.
Tags: Bridge Engineering Bridge Maintenance Bridge Construction Bridge Maintenance Bridgent Products
Westcoast New Area, Qingdao City ,Shandong Province ,China
