Products & Systems / Structural GRP profiles
GRP structural connections
Design the joint.
Resolve the interface.
Connect GRP members, fasteners and the supporting asset within one design. Define the forces, local material behaviour and installation requirements before the fixing schedule is issued.
The complete load path
A fixing is one part
of a working connection.
The joint has to transfer the intended actions between components. Its resistance and stiffness depend on the members, local geometry and fastening arrangement together.
Member to member
Define how the forces pass between profiles. Review the connection geometry, local bearing, remaining material and any joint movement allowed in the design.
Component to frame
Locate deck restraints, guarding attachments and equipment connections. Include the actions introduced into the supporting member.
Frame to asset
Set out the base or support detail and reactions. Confirm the substrate, anchor arrangement and the supporting asset’s ability to receive the forces.
A strong fastener cannot compensate for an unsuitable profile detail or an unverified substrate. Keep the calculation, connection drawing and installation instructions aligned.
Detail the actual joint
Specify the holes.
Support the contact.
Agree the connection layout before fabrication. A bolt diameter alone leaves the geometry and local behaviour unresolved.
Actions and offsets
Identify force directions and load combinations, including offsets from the member or fixing line. Reflect these in the joint design.
Hole layout
Dimension diameters, centres, spacing and edge distances from clear datums. Identify slots, tolerances and any permitted movement.
Local profile checks
Review bearing, the section remaining around holes and other relevant local failure modes using the material and design method for the actual component.
Contact and washers
Specify the contact surfaces, washers, plates or other load-distribution details required. Check hollow-profile walls and access inside the section where relevant.
Fastener specification
Identify material, grade and corrosion suitability, with the required tightening method. Use the instructions for the designed GRP joint rather than assuming a steel connection procedure.
For pultruded members, identify the selected profile grade and orientation. The BS EN 13706 series supports product specification; the joint still requires its own design.
The supporting asset matters
Establish the substrate.
Select the anchorage.
Confirm what the support actually is and how it behaves. Existing construction may need investigation before the anchor design can be completed.
| Establish | Information for the anchor design |
|---|---|
| Base material | Concrete or masonry type, condition, available thickness and relevant strength information. |
| Geometry | Edges, joints, anchor spacing, fixing positions and any constraints on embedment. |
| Actions | Tension, shear and their combinations, together with the base or bracket arrangement. |
| Site constraints | Reinforcement, concealed services, drilling access and the permitted installation method. |
| Exposure | Temperature, moisture, chemical conditions and corrosion requirements for the selected anchor. |
BS 8539:2012+A1:2021 addresses selection and installation of post-installed anchors in concrete and masonry. BS EN 1992-4:2018 addresses fastening design for concrete. Apply the relevant requirements and product information to the actual detail.
Agree the purpose before testing
Make site testing
answer the right question.
Where testing is required, the project team should define what it needs to establish. Record the agreed scope and criteria before work starts.
Purpose
Identify whether the work concerns the substrate or the verification of installed anchors. Agree how the results will be used in the design or acceptance process.
Method
Specify the test locations, equipment, procedure, loading and acceptance criteria through the responsible designer and testing parties.
Record
Keep the anchor identification, substrate, installation information and results together. Refer unexpected results for review before release.
A pull-test result is specific to its test conditions. It does not establish every aspect of the support, joint or assembled structure.
From drawing to installed detail
Prepare consistently.
Check before release.
Use the accepted detail and the applicable product instructions. Ensure the people installing and checking the connection have the information needed for the task.
Record the specified checks and resolve differences before the assembly is released for use. Keep the final connection arrangement available to the receiving team.
Preparation
Check the substrate and set-out before drilling. Follow the specified hole preparation and installation process for the chosen anchor or fastener.
Assembly
Confirm components, contact surfaces and tightening requirements. Review unexpected gaps, damaged profiles or site differences before proceeding.
Inspection
Record the specified checks and any required tests. Keep concealed details and accepted changes within the project record.
Handover
Pass on the final arrangement and relevant inspection requirements. Review later alterations against the original design basis.
Coordinate the connection package.
Send the context with the detail.
Include member sizes, forces, adjoining materials, substrate information and the current drawing revision.
Questions about GRP connections.
Can I use a standard steel joint detail?
Do not assume it transfers directly to GRP. Review material properties, local behaviour, contact and fastener requirements for the actual members.
Does a larger bolt improve the joint?
Not necessarily. A larger hole changes the remaining profile material and edge geometry. The complete joint needs to be reviewed.
Do all anchors need a pull test?
The requirement and purpose depend on the project, substrate and specification. Agree the test scope and acceptance process with the responsible parties.
Can site holes be moved to avoid reinforcement?
Refer the proposed change for review. Anchor spacing, edge distances and the connection geometry may all be affected.
What should be included in the connection enquiry?
Provide the sketch, forces, member dimensions, connected materials, substrate information and site constraints, with the scope of review required.
Resolve the joint.
Send the connection detail.
Share the drawing and design inputs. Ask Vital to review the member, fastener and substrate interfaces for your package.