AA. Bridge Machinery¶
1. Purpose¶
To ensure that completed machined bridge components meet the dimensional, fit and finish requirements for integration into the bridge. These machined components may be: stand-alone components – items used independently of other machined items that are installed directly to the structure (eg: live load shoes, centering devices and bridge bearings); part of an assembly where they mate with other fabricated items or the existing structure with critical dimensions existing on both components (eg: turned bolts, span locks, bearings and shafts); a full drive-train for operation of a bascule leaf, span lock, tail lock or other assembly. Shop inspection and assembly (when enough components are available) will be performed to ensure adherence of machined component fit and compatibility with the mating components.
2. Definitions¶
For readability, this section uses the following definitions and abbreviations.
- 2.1 FCM: Fracture Critical Material
- 2.2 RFI: A formal communication from Seacoast to the customer asking for clarification on a topic.
- 2.3 RFM: A formal communication from Seacoast to the customer asking for approval to use a material that is a change from original specifications.
3. References¶
- 3.1 Seacoast Inc. Quality Control Plan (Section A)
- 3.2 Applicable ASTM Standards
4. Responsibilities¶
- 4.1 Owner of Process: The engineering manager will review and approve any changes to this procedure. The procedures will be reviewed periodically and at a minimum, annually.
- 4.2 Quality Control (Manager): The quality control manager will approve the final procedures before deployed to the Quality Manual.
- 4.3 Engineering Manager: The engineering manager must approve the job specific shop machining procedures, developed as part of this procedure.
- 4.4 Owner: By contract, the owner may also require approval of the job specific shop machining procedure by the owner's representative engineer.
- 4.5 Shop Foreman: Responsible for reviewing the machining requirements in the prefabrication meeting and ensure staff follows procedures.
- 4.6 Shop Staff / Machinist: Responsible to follow these procedures and any job specific machining procedures if applicable.
5. Quality Records¶
Unless otherwise noted, all Quality Records follow the Seacoast "Policy for Maintenance of Quality Records" documented in the QCM Quality Control Plan (Section A-page 13)
- 5.1 Detailed Drawings: Retained for 2 years from the project completion date.
- 5.2 Job Specific Documentation (if required): Filed in the Job Book and retained for 2 years after the completion of the Job. Job specific machining procedures may also include a table to record critical measurements, including applicable tolerances for each of the measurements and the accuracy of the measurement to be taken, or may include actual measured dimensions red-lined onto the shop drawings.
6. Documentation¶
6.1 Standard Practice¶
The Quality Manual of Seacoast, Inc. is to be followed in the production of bridge machinery, supplemented by more specific criteria contained in this section when required. Bridge Machinery requires additional considerations because of the complexity of mating bridge machinery parts with existing and/or new structural components. Coordination with the structural supplier or existing field conditions is paramount.
6.2 Bridge Machinery Supplemental Procedures¶
Seacoast, Inc. follows the procedures in the Quality Manual at a minimum. Bridge Machinery is complex and additional considerations are required when working on or producing bridge machinery parts. This procedure identifies what to document and consider when deciding if supplemental job specific bridge machinery procedures are required.
| Topic | Supplemental Procedure (Consideration) |
|---|---|
| Contract and Specification Review | As machinery typically mates with structural components, and the two are often designed by different parties, review of all machinery and structural details must take place to ensure the items are compatible. Review for conflicts between structural details and the ability to install or operate the machinery component. Review for compatibility of connections between the machinery component and the structure. Ensure that existing field dimensions can be properly determined, where they will be required. If conflicts exist between the plan details and the specifications or existing conditions, initiate the RFI/RFM process. |
| Detailing | Bridge Machinery components must be detailed to include all pertinent characteristics. Consideration must be given to the installation and alignment of the machinery component after the fabrication is complete. Often conflicts between the structure and the machinery will not be noted until detailing is in progress. Contract and specification review is, therefore, continued through the detailing process. When detailing: Include the tolerance for all dimensions of the components, either specifically for the fit required or by a standard tolerance table in the drawings, if the specific fit is not required. Base tolerance on the fit required, shared by the capability of the machine or tooling forming the part and that used to form the mating part, or bolt hole. If mating components are being fabricated by other providers, ensure compatibility of tolerances. Ensure the structural details are considered for how the component can be installed. Where existing conditions cannot be determined, detail the components to leave flexibility in installation, where possible, or determine if the existing component can be replaced as well. Where a finish is required, ensure the machining process necessary to fabricate the part can produce the finish. If the two are incompatible, initiate the RFI/RFM process. Shop drawings must include all material requirements, including supplemental tests, necessary for the proper procurement of materials, finished or unfinished. Consider the final location of welds and ensure machining will not remove weld material that is necessary for the overall strength or integrity of the final part. Select material sizes to provide machine stock, to allow anticipated distortion to occur prior to machining the component to the final dimensions. |
| Welding Process and Distortion Control | Welded components that are to be machined to become Bridge Machinery will be welded according to the Quality Manual and any supplemental contract requirements. Consider material hardness or other properties affected by welding that can alter the machinability of the material. Use the appropriate process and material to ensure the final product can be produced. Prior to any welding, determine the steps necessary to produce the final product, considering when partial fabrications will be machined, to allow access to weld, to allow access to machine and to ensure the final product meets the necessary tolerances for flatness, squareness and basic assembly requirements. Typically, due to distortion from weld cooling, a component should be heat-treated for stress-relief prior to machining to minimize springing during the machining process. Consider pre-heat and post-heat that may not be required to achieve the appropriate weld but would assist in distortion control before or during machining. |
| Bolt Installation | Where necessary, fabricate items with undersized bolt holes, for the holes to be finished in the field, at installation, to provide the proper fit with turned bolts. |
| Painting | Paint selection must consider the condition of the material to be painted. Machine finished surfaces require epoxy paints, or must be blasted to provide adequate anchor profile for zinc primer. If magnetic drills are to be used in the field for installation, limit coatings to primer only, when possible, to allow the drill magnet to adhere properly – applying the intermediate and finish coats after all drilling is complete. |
| Inspection and Testing | Inspection of component dimensions and finish will be completed in accordance with the procedures outlined in the Quality Manual. Instruments (measuring tools) used will include micrometers (inside, outside, depth), calipers, feeler gauges, dial indicators and similar. Measurements will be taken as machining is progressing, ensuring rough cuts are completed first leaving a small amount of material removal for final cuts to provide appropriate surface finish. Material property testing must be completed prior to acceptance of raw or partially completed materials, if completed by the supplier or as a function of acceptance of the material, if completed in-house. Acceptance criteria will be established by the governing material specification, typically an ASTM, including all supplements specified in the Contract Documents. |
| Calibration of Tools and Equipment | Measuring tools must be checked against standards weekly, and any time there is cause to question the accuracy of the tool. Measuring tools shall be adjusted for proper calibration whenever they are found to not match the standard. Measuring tools must be replaced if they vary from the standard three consecutive times of being checked. |
| Non-conformance, and Corrective Action | Non-conformance and corrective action need to consider the overall tolerance of the machinery items with their mating components. Often an item out of tolerance for an individual part may be in tolerance as an assembly with the mating part. This possibility needs to be examined when considering the acceptability of machined components. Additionally, the mating component may not have been completed and the final dimensions, with tolerance, of the mating component may be adjusted before completion to bring the assembly into acceptance. |
| Purchasing | Purchasing must include the additional testing requirements that may be required either by the Contract Documents, particularly any required Supplemental requirements chosen to apply from the ASTM specification. Castings, in particular, require UT, to ensure porosity is within limits. Forgings often require supplemental strength or toughness tests. |
| Receiving | Materials that require supplemental testing performed by the provider will not be accepted until the test results have been provided indicating acceptable material. These tests are performed in addition to normal MTR requirements. |
6.3 Quality Assurance¶
Measurements and quality control will be performed by the Machinist and Shop Foreman. Quality assurance will be provided in-house by the engineer or other qualified technician. Third party QA personnel will be given access and the opportunity to witness machining, witness measurements or perform independent measurements as necessary to qualify the acceptance of the in-progress and finished components. Where the client requires third party QA personnel, the client will be notified as far in advance of production as possible – often the contract determines the minimum amount of advance notice required.
Finished components provided by outside suppliers will be inspected at receiving and acceptance will be further determined by the engineer or other qualified technician. Purchased final products will typically be:
- Shims
- Roller bearings
- Couplings
- Turned bolts
- Bushings
Where possible, finished Bridge Machinery components will be partially, or fully, shop assembled to ensure compatibility.
7. Revision History¶
| Revision Date | Approved By |
|---|---|
| 2026-05-12 | Engineering Manager |
Summary of Change: Reformatted to standard procedure template.