Replacement Bridge Bearings: Site Measurements and RFQ Information

Replacement starts with evidence, not a like-for-like assumption

A replacement-bearing inquiry is different from a new-build product request because the existing structure, site constraints and asset condition become part of the technical brief. The goal is not to diagnose a bridge remotely or promise a replacement method from a photograph. The goal is to gather enough evidence for the responsible project team to decide what must be investigated, what can be measured and which documents need to accompany a quotation request. A bearing with the same outside dimensions may not be a like-for-like answer if actions, movement, interfaces, deterioration, access or owner requirements have changed.

Start by separating three possible scopes: inspection/assessment, repair/refurbishment and replacement. A project may need only one of these, or it may need evidence from an assessment before the scope can be chosen. In an RFQ, state the requested scope and identify what is known from records, site survey and approved analysis. Do not infer that a supplier provides field services, jacking, temporary works or installation simply because a replacement bearing is being discussed. Those responsibilities must be defined by the project and confirmed against the actual offer.

Identify the existing asset and available records

Begin with the bridge name or asset reference, location, structure type, support location, bearing identifier and any original drawings, schedules, product records, inspection reports or previous repair information. Match each site photograph and measurement to a support location so that images do not become detached from the bearing schedule. If the asset has multiple similar supports, a simple location plan with marked positions is more useful than a folder of unnamed photographs.

The records should also indicate whether the existing bridge layout has a defined fixed point, guided bearings, free movement locations, expansion joints or separate restraint elements. These facts help the project team understand what the old arrangement was intended to do, but they do not prove that it remains adequate. The relevant current actions, movement assumptions, support condition and owner requirements must be checked through the project’s responsible engineering process. Where records are missing, list that gap in the RFQ instead of inventing a bearing type from visual appearance alone.

For a related project route, review Elastomeric Bearings or Pot Bearings or Spherical Bearings in the context of Seismic Retrofit.

Measure the interfaces, not only the old bearing

An RFQ should capture the available envelope around the bearing as well as the component itself. Record plan dimensions, overall height, top and bottom levels, pedestal and superstructure geometry, plate or anchor details, hole locations, edge distances, clearances, nearby reinforcement or diaphragms, access routes, drainage or water condition and any visible interface constraints. Identify the measurement datum and whether a figure is surveyed, taken from a drawing or estimated from a photograph.

Measurements should be made and interpreted by appropriate project personnel. This article does not prescribe a site procedure or claim that a set of photos can confirm installation condition. Its purpose is to make the information boundary clear. The bearing supplier needs a picture of the support interface so that the requested product scope can be discussed against actual constraints. The project engineer and contractor remain responsible for site safety, survey quality, temporary works, lifting, traffic or rail control and any construction method decisions.

Record function, actions and movement before calling it like-for-like

The existing arrangement may have been fixed, guided, free or part of a broader restraint strategy. Identify what the drawings say about its intended function and how that function relates to the full bridge. Then provide the current or governing project actions, translations and rotations by axis. Changes in bridge use, rehabilitation, geometry, expansion-joint behaviour, seismic assessment, settlement, exposure or owner requirements can mean that the replacement question is not identical to the original procurement question.

State the bearing position, local axes, guide direction and whether a separate key, stop, pin or connection element participates in restraint. Include minimum reactions, uplift or exceptional actions where relevant, but always identify the source and load basis. The RFQ does not need to contain a complete calculation package if the project has not issued one. It should identify which engineering data are approved, which are preliminary and which must be supplied later. That makes it possible to compare a quotation assumption with the project record rather than with an unlabelled number.

Describe site and programme constraints without prescribing a method

Replacement projects often have constraints that do not appear in a new-build catalogue. These can include live traffic or rail operations, possession windows, restricted access, overhead or adjacent utilities, limited lifting space, jacking questions, temporary support needs, environmental protection, storage limitations, delivery sequence and required approvals. Put these constraints in the RFQ as questions or project facts, not as generic instructions. A supplier may need them to define product interfaces, packaging, marking or document scope, while the responsible contractor and engineer determine the actual means and methods.

Handling and restraint information should be controlled for the exact assembly and project stage. Do not assume that a shipping restraint, lifting point, storage condition or disassembly approach from another product or supplier is applicable. Before moving or installing any assembly, the responsible parties need the approved project-specific lift plan, handling instructions, condition checks, orientation information and authorization route. The RFQ can identify these documentation needs without attempting to replace them with a web-page procedure.

Define the requested supply and document package

Ask suppliers to separate the bearing assembly from possible adjacent scope. Depending on the project, the quotation may need to address upper or lower connection plates, anchors, guides, sliding components, protection, identification, drawings, material records, dimensional inspection, testing/witness requirements, packing, delivery sequence and handover documents. The RFQ should not assume every item is included. It should ask the supplier to identify inclusion, exclusion, assumptions and information still required.

Document types also need clear roles. A drawing coordinates interfaces and dimensions. A data sheet may support screening. A quality or inspection record documents an agreed control activity. A site handling or installation document, if applicable, must identify the exact assembly and revision. An owner may require additional approval, inspection or independent checking steps. List these requirements rather than using a generic statement such as “full certificate package.” That makes the commercial comparison more accurate and reduces the risk of a critical document being discussed only after delivery.

Prepare a disciplined replacement-RFQ package

A strong package includes a short scope statement, asset and bearing identifiers, location plan, existing drawings/schedules, condition photographs, site measurements with datum, current or required actions/movements/rotations, local axes and restraint intent, support/interface details, environment, access and programme constraints, requested quality/documents, quantity and delivery sequence. Add a log of unknowns: missing original drawings, pending survey data, unclear guide orientation, incomplete action information or owner decisions that have not yet been made.

The supplier can then respond to the actual product and documentation request while showing any assumptions that need project confirmation. If assessment, repair and replacement are all potential outcomes, keep them separate in the request. This prevents a product quotation from being read as a field-service proposal or a site condition assessment from being treated as a manufacturing release. The result is a more transparent technical handover among owner, engineer, contractor, inspector and supplier.

Before approval or delivery

Before a replacement bearing is released, the project should confirm that the selected scope matches the approved bearing schedule and support detail; actions, movements, rotations and restraint direction have been reviewed; the supply boundary is clear; drawing and document revisions are controlled; marking matches the location plan; packing and delivery sequence are agreed; and the responsible parties have the applicable project instructions for site handling, restraints, lifting, storage and installation readiness. These checks are not a construction method statement. They are document-control gates that ensure the right questions have reached the right responsible party.

A replacement project is successful when the evidence travels with the decision. Use the RFQ to collect the current facts, retain unknowns visibly, separate product scope from site responsibilities and preserve the need for project-specific engineering verification. That approach gives a supplier enough context to respond clearly while avoiding unsupported promises about existing condition, construction method or final bridge performance.