BS 1377-9:2025 marks an important update for UK ground testing, site verification and construction compliance. For many site teams, the most familiar part of this standard is the plate bearing test, also widely called the plate load test.
The practical change is simple but important: the long-standing reference to BS 1377-9:1990 is now being replaced by BS 1377-9:2025 for in-situ soil testing. That matters for specifications, quotations, method statements, site test requests, reporting formats and how engineers interpret ground performance evidence.
The plate bearing test itself remains a field test used to measure how ground, formation or a prepared working platform responds under load. But the standard behind the test has moved on, and UK construction teams now need to understand what that means in practice.
The key message for contractors and engineers is this: BS 1377-9:2025 does not make plate bearing testing a new test. It updates the technical standard that should be referenced when requesting, carrying out and reporting in-situ soil tests. The biggest practical risk is not the test itself, but old specifications, vague test requests and reports that do not clearly state the standard, load, plate size, location, acceptance basis and limitations.
Jump to: What changed | Old vs new | Plate bearing test impact | What site teams should update | Common mistakes | Checklist | FAQ
What Has Changed?
BS 1377-9:2025 is the updated British Standard for methods of test for soils for civil engineering purposes, specifically in-situ tests. The previous 1990 version had been used across UK construction for decades and appears in many old specifications, ground investigation documents, temporary works designs and testing schedules.
For plate bearing testing, the change means that project teams should no longer casually refer to “BS 1377 Part 9:1990” as the default current standard unless there is a specific contractual reason to do so. New specifications, test requests and reports should be checked so that they refer to the current standard where applicable.
This is especially important because plate bearing testing is often used to support real construction decisions: whether a formation is acceptable, whether a working platform is performing as expected, whether compacted fill has sufficient response, or whether the measured settlement behaviour is within the project’s acceptance criteria.
BS 1377-9:1990 vs BS 1377-9:2025: The Practical Difference
| Area | Old Position | 2025 Practical Position |
|---|---|---|
| Standard reference | Many specifications still refer to BS 1377-9:1990. | New project documents should check whether BS 1377-9:2025 is the correct current reference. |
| Testing context | Often treated on site as a generic “plate test”. | The test should be requested as a defined in-situ test with clear scope, load, plate size, location and reporting output. |
| Reporting expectation | Reports may vary widely depending on provider and project brief. | Reports should be clear about what was tested, how it was tested, what was measured and what limitations apply. |
| Acceptance criteria | Sometimes assumed by site teams or left unclear. | Acceptance should be provided by the engineer, designer, temporary works designer or project specification before testing. |
| Use of result | Sometimes treated as a general pass certificate for the site. | The result should be treated as localised evidence at the tested position, interpreted against the actual project loading case. |
What This Means for Plate Bearing Testing
A plate bearing test applies load through a steel plate onto the ground, formation or platform surface. Settlement is measured as the load is increased, maintained and, where required, reduced. The resulting load-settlement behaviour helps the engineer understand how the tested location responds under controlled loading.
STRUCTinspect has explained the wider test principle in Plate Load Testing Explained for Construction Projects. The important point is that the test produces local ground response evidence. It does not automatically prove that an entire site, working platform or formation is suitable everywhere.
Under the 2025 standard environment, the practical focus should be on clarity. The test request should identify the standard, plate diameter, load or pressure, load sequence if specified, test level, location, reaction arrangement, measurement method, required output and acceptance criteria.
Without that information, a plate bearing test can still produce numbers, but those numbers may not answer the engineering question the project actually needs to resolve.
Why This Matters for Working Platforms
Working platforms are one of the most common reasons plate bearing tests are requested. Piling rigs, cranes, piling attendant plant and other heavy equipment rely on the platform and underlying ground behaving as expected throughout the works.
A plate bearing test can support working platform assessment because it measures local settlement response under a loaded plate. However, it does not replace the working platform design, platform construction control, drainage, inspection, maintenance, exclusion management or plant movement controls.
STRUCTinspect has covered this separately in Plate Load Test for Working Platforms: What Site Teams Need to Know. The same principle applies under BS 1377-9:2025: the test result should be read against the platform design and project acceptance criteria, not used as a blanket approval for all future loading.
Related STRUCTinspect Guidance
What Contractors and Engineers Should Update
The arrival of BS 1377-9:2025 means contractors, engineers and testing providers should review the language used in project documents. Many older templates, specifications and quotation requests still refer to BS 1377-9:1990 by default.
This does not mean every historic document must be rewritten immediately. But for new work, the project team should be deliberate. If the current standard is intended, say so. If an older standard is contractually required, that should also be stated clearly and understood by the parties involved.
| Document or Process | What to Check | Why It Matters |
|---|---|---|
| Project specification | Does it still cite BS 1377-9:1990? | Old references can create confusion between contract requirements and current testing standards. |
| Testing quotation | Does it state the test standard and requested output? | A vague quote may not cover the report content the engineer expects. |
| RAMS | Does the method align with the intended test standard and site controls? | Testing involves loading, reaction systems, exclusion zones and settlement monitoring. |
| Test request | Are load, plate size, level, location and acceptance basis defined? | The test cannot answer a design question that has not been properly stated. |
| Final report | Does it separate measured data from interpretation? | The tester records behaviour; the responsible engineer normally decides whether it satisfies the project requirement. |
The Reporting Issue: Data Is Not the Same as Approval
One of the most important lessons from the updated standard environment is that a plate bearing test report should not be treated as a generic approval certificate unless the acceptance route is clearly defined.
A good report should state what was tested, where it was tested, how it was loaded, what settlement was measured, what the ground condition looked like, what reaction system was used and what limitations apply. It should also record the requested load or pressure and any acceptance criteria supplied before testing.
This is especially relevant for working platforms. If the test was carried out at one location on a platform, the result should not be automatically applied to untested areas, different platform build-ups, different weather conditions or different plant loading arrangements.
The distinction is important: the test provider supplies measured evidence. The designer, engineer or temporary works team normally decides what that evidence means for the intended construction load.
Common Mistakes After the Standard Update
The 2025 standard update is likely to expose existing weaknesses in how plate bearing tests are requested and used on site. The following mistakes are common on construction projects.
| Mistake | Why It Is a Problem | Better Approach |
|---|---|---|
| Requesting “a plate test” with no standard stated. | The tester may not know what method, output or reporting basis the project expects. | State the test standard, test purpose and required result format. |
| Using old BS 1377-9:1990 wording in new specifications without review. | It may conflict with the current standard position or create ambiguity in procurement. | Update templates and confirm the intended standard with the engineer. |
| No design load or bearing pressure provided. | The test may not relate to the actual construction loading case. | Ask the designer or temporary works engineer to specify the target load or pressure. |
| No acceptance criteria provided. | The report may show settlement data but not support a clear decision. | Agree settlement, bearing, stiffness or project-specific acceptance criteria before testing. |
| Treating one test as proof of the whole site. | Ground and platform conditions can vary significantly across a site. | Select representative and risk-based locations, with more tests where conditions vary. |
Plate Bearing, CBR, DCP and LWD Are Not the Same Thing
Another practical issue is test confusion. Plate bearing testing, CBR testing, DCP testing and Light Weight Deflectometer testing are often discussed together, but they do not measure the same behaviour.
A plate bearing test measures load-settlement behaviour under a loaded plate. A CBR test gives a California Bearing Ratio value, commonly used for pavement and subgrade assessment. A DCP test measures penetration resistance with depth. An LWD test measures dynamic surface deflection and stiffness-related response.
STRUCTinspect has explained these differences in Light Weight Deflectometer Test: What It Measures on Construction Sites and CBR Test in Construction: What the Result Means for Subgrade Design.
| Test | Main Evidence Produced | Common Use |
|---|---|---|
| Plate bearing test | Load-settlement response under a plate. | Bearing and settlement evidence for formations, platforms and compacted layers. |
| CBR test | California Bearing Ratio percentage. | Subgrade, pavement and road design assessment. |
| DCP test | Penetration resistance with depth. | Identifying shallow weak layers, variability and relative resistance. |
| LWD test | Dynamic deflection and stiffness-related response. | Rapid comparison of compacted layer consistency. |
Checklist Before Requesting a Plate Bearing Test Under BS 1377-9:2025
Before booking a plate bearing test, the project team should confirm the information below. This avoids wasted mobilisation, unclear results and reports that do not answer the engineer’s question.
- Test standard: confirm whether BS 1377-9:2025 is required.
- Purpose of test: formation approval, working platform assessment, compacted layer check, bearing evidence or other requirement.
- Plate size: confirm the required plate diameter.
- Test location: provide a drawing, grid reference, marked location or agreed site instruction.
- Test level: confirm whether testing is on formation, capping, platform surface, sub-base or another layer.
- Maximum load or pressure: this should come from the engineer, designer or temporary works designer.
- Loading sequence: confirm if a project-specific sequence is required.
- Settlement criteria: confirm allowable settlement, residual settlement or other acceptance criteria.
- Required output: confirm whether the report needs bearing pressure, load-settlement curve, modulus-related output, photographs or location plan.
- Reaction load: confirm plant, kentledge, vehicle or other reaction arrangement.
- Access and safety: confirm working area, exclusion zone, traffic management, ground conditions and safe reaction setup.
- Interpretation responsibility: confirm who will decide whether the measured result satisfies the project requirement.
RAMS and Site Safety Still Matter
Plate bearing testing involves applying load, setting up a reaction system, measuring settlement and controlling the work area. That means the RAMS should not be treated as generic paperwork. The method should reflect the actual site arrangement, reaction load, access, exclusion zone and test load.
STRUCTinspect has covered wider testing safety principles in What a Structural Testing RAMS Must Contain Before Loading Starts. Those principles apply to plate bearing tests because loading operations need clear control, competent supervision and safe separation from other site activities.
What the New Standard Means Commercially
The commercial impact of BS 1377-9:2025 is likely to be felt through specifications, procurement and reporting expectations. Contractors may find that clients, consultants and quality teams begin asking for the new standard reference in quotations, method statements and final reports.
Testing providers may also need to review their templates, calibration references, report wording, scope descriptions and internal procedures. Where accreditation applies, the provider should also check how the standard update affects their accredited schedule and reporting statements.
For principal contractors, the safest approach is to stop relying on vague wording such as “plate test required” or “test to old BS 1377”. Instead, issue a clear brief that tells the testing company exactly what is required and tells the engineer exactly what evidence will be produced.
What This Does Not Mean
The publication of BS 1377-9:2025 does not mean that every previous plate bearing test report is suddenly invalid. Reports should be understood in the context of the standard, specification, test date, project requirement and contract under which they were produced.
It also does not mean that a plate bearing test can replace design. The test provides measured ground response at a specific location under a specific loading arrangement. Engineering judgement is still required to decide whether that evidence is adequate for the proposed use.
Finally, this article is not a substitute for reading the official British Standard. The official BS 1377-9:2025 document should be used for the detailed apparatus, test procedure, calculations, reporting requirements and technical clauses.
Evidence-Based Summary
BS 1377-9:2025 updates the standard reference for in-situ soil testing, including plate bearing testing.
For UK construction, the main practical impact is on specifications, test requests, RAMS, reporting language, acceptance criteria and how test results are used.
Plate bearing testing remains a local load-settlement test. It should not be treated as a blanket approval for an entire site, formation or working platform.
The strongest project approach is to define the standard, purpose, plate size, load, location, acceptance basis and interpretation responsibility before the testing team arrives on site.
FAQ: BS 1377-9:2025 and Plate Bearing Tests
What is BS 1377-9:2025?
BS 1377-9:2025 is the updated British Standard covering in-situ methods of test for soils for civil engineering purposes. Plate bearing testing sits within the wider family of in-situ soil tests covered by this standard.
Does BS 1377-9:2025 replace BS 1377-9:1990?
Yes. BS 1377-9:2025 is the current standard and BS 1377-9:1990 is listed as withdrawn. Project teams should check new specifications and test requests to make sure the correct standard is being referenced.
Is a plate bearing test the same as a plate load test?
In UK construction, the terms are often used interchangeably. The test applies load through a plate and measures settlement response. The important point is to define the standard, plate size, load, location and required output clearly.
Does the new standard change the purpose of plate bearing testing?
No. The purpose remains to obtain measured in-situ ground response under a loaded plate. The practical change is that specifications, reports and test requests should now align with the current standard where applicable.
Can a plate bearing test approve a working platform?
A plate bearing test can support working platform assessment, but it should not be treated as a blanket approval. The result needs to be reviewed against the working platform design, plant loading, platform construction, drainage, inspection regime and acceptance criteria.
Who should provide the test load or acceptance criteria?
The required load, pressure and acceptance criteria should normally be provided by the engineer, designer, temporary works designer or project specification. Testing providers should avoid guessing the design requirement.
Is a plate bearing test the same as CBR, DCP or LWD testing?
No. A plate bearing test measures load-settlement response under a plate. CBR, DCP and LWD tests measure different behaviours and should not be treated as direct replacements unless the project specification accepts a defined relationship.
Do old plate bearing test reports become invalid?
Not automatically. Historic reports should be read against the standard, specification, contract, date and project requirement under which they were produced. New work should use the correct current reference unless the contract states otherwise.
Source Context and Editorial Note
This article is a STRUCTinspect technical explainer based on the publication of BS 1377-9:2025 and its practical implications for plate bearing testing, working platform assessment and construction ground verification in the UK.
It is not a clause-by-clause summary of the British Standard and does not reproduce the official test method. The official BS 1377-9:2025 document should be consulted for apparatus, procedure, calculations, reporting requirements and technical compliance.
This article does not provide engineering, geotechnical, temporary works, legal, contractual or construction advice. Plate bearing test requirements should be confirmed by the project engineer, geotechnical designer, temporary works designer, specification author or competent professional responsible for the works.
