ITP generator — earthworks and fill

Class, place, compact, prove — with the acceptance criteria a highway ITP actually carries, including the plant limits nobody writes down until an inspector asks.

Earthworks is the scope where the requirement is almost never in the clause you cite. SHW Series 600 tells you what to control; the contract-specific Appendix 6/1 holds the acceptable material classes, and Appendix 6/4 the compaction requirement. An ITP that cites “Series 600” and stops has documented that a rule exists, not what it is — and that is one of the most common review comments there is.

It is also the scope with the shortest evidence window. As-revealed ground conditions are recordable for as long as they are open. Once the fill is on, the only record is the one somebody made at the time.

It is free and there is no sign-up. Type the scope, read the whole plan on screen. Where the tool has not been given your specification, project-specific criteria come back marked TBC — EVIDENCE REQUIRED with the document that would close them named. That is the correct answer, not a limitation politely worded — an ITP that quietly fills a tolerance with a typical value is worse than one that leaves the box open, because somebody signs the first one.

What controls earthworks and fill

These are the documents an acceptance criterion on this scope has to agree with. A criterion that restates the activity and attaches a reference is doing half the job.

• MCHW Specification for Highway Works, Series 600 — Earthworks — classification, acceptability, placing, compaction, tolerances. OGL, and the source of the class system (Table 6/1). The Clause carries the rule; the contract Appendix carries the number. Cite both.
• MCHW Series 800 — Unbound and hydraulically bound mixtures — capping and sub-base.
• BS EN 13251 — Geotextiles and geotextile-related products for earthworks and foundations. The declaration of performance goes to the lead designer BEFORE placement, not with the handover pack. That timing is itself a hold point.
• PD CEN/TS 17006 — Continuous compaction control. Where the earthworks support or could affect a running line, continuous compaction control is commonly specified rather than spot testing.
• BS 5930 / BS EN 1997 — Ground investigation and geotechnical design — the basis for termination criteria.

The inspection sequence, and where the gates fall

Hold points belong where the evidence stops being recoverable, and the test is always the same question: what becomes invisible next? On this scope that puts 7 of the 18 steps below at a hold point — the rest are witness points, surveillance, review or recorded inspection depending on your contract and on who is watching.

1. [H] Material approvals against the fill classification table — Placing unacceptable material is not a snag, it is an excavation.
2. [H] Geotextile and geogrid declarations of performance submitted to the lead designer — Required before placement, not with the records.
3. Consents and certificates in place; archaeology decision record
4. Ground investigation instrumentation protected, top levels recorded
5. Existing land-drainage survey
6. Pre-earthworks trial trenching to confirm presence or absence of residual geotechnical hazards
7. Site clearance and topsoil strip; stockpiles located, classified and recorded
8. [H] As-revealed ground conditions inspected, mapped and recorded by a qualified engineering geologist — The only window there will ever be. Adverse conditions reported at the time, not reconstructed later.
9. Identification of periglacial features, soft ground and dissolution features needing mitigation
10. [H] Demonstration area (commonly 700 m²) accepted by the assurance body — An explicit hold point in the corpus — works do not progress past it.
11. [H] Foundation termination criteria — undrained shear strength by hand vane or DCP, stiffness by plate-loading modulus, to the appendix testing grid
12. Fill placing and compaction by method or end product as required for the class
13. [H] Fill to structures — restricted plant list within 2 m
14. Sub-formation and capping; geotextile separator where granular meets cohesive
15. [H] Formation preparation and proof roll — The pavement covers it next.
16. Instrumentation and monitoring installed at the correct stage
17. Drainage — V-ditches, channels, French and toe drains, relief wells to the TW design
18. Surface level tolerance checked against the earthworks tolerance table

One rule that catches people and is not negotiable: hold points cascade upward. Where the client, the designer or a third party has identified an intervention as a hold point, it is a hold point in your column too. You cannot accept theirs and keep yours as a witness.

Acceptance criteria that survive a review

The acceptance-criteria column header in one real template is the whole test: what answer should we get if it is right? If the entry does not let a third party, months later, decide pass or fail from the record alone, it is not an acceptance criterion. These are from issued ITPs on this scope — not composed as illustrations:

• Compaction plant used on fill to structures within 2 m of the structure limited to: vibratory roller ≤1300 kg per metre width of roll and ≤1000 kg total mass; vibrating plate compactor ≤1000 kg; vibro-tamper ≤75 kg. Compacted level within this zone not to differ from the adjoining fill by more than 250 mm.
• Stockpiles not exceeding 5 m height; topsoil not stockpiled for more than five years; stockpiles sealed against water ingress, signposted with classification.
• Where formation or sub-grade is softened by precipitation or site activity, strip by at least 40 mm to expose a competent sub-formation and re-compact.
• Geotextile minimum overlap 500 mm; exposure to sunlight not to exceed 5 hours; not placed during extreme heat, extreme cold, heavy rain or frost.
• Class 1A on-site grading (Table 6/2): 100% passing 125 mm, 95–100% passing 90 mm, less than 15% passing 63 µm.

Against which, the ones that get marked every time: as per design · as specified in the material approval form · as per manufacturer’s instruction · document accepted · within accepted tolerances · acceptable to use · visual inspection · see notes. They fail for one reason: they defer the criterion to a document the inspector does not have on the deck, and they give the person signing nothing to be wrong about.

What comes back TBC on this scope, and where it comes from

The generator does not have your specification, so it will not invent these. It marks them and names the document that would close them:

• Appendix 6/1 — which material classes are acceptable on this contract
• Appendix 6/4 — the compaction requirement, and whether it is method or end product
• The testing grid and frequency from the appendices
• Formation and capping level tolerances
• The termination criteria values — shear strength or modulus — from the geotechnical designer

Other scopes

• ITP generator — in-situ reinforced concrete
• ITP generator — drainage
• ITP generator — formwork and falsework
• ITP generator — precast erection
• ITP generator — waterproofing

Why the generated draft is a draft, and stays one

Starting permanent works without an accepted ITP is a critical non-conformance in its own right, and proceeding through a hold point gets an NCR raised against you. Before this output is issued it needs the project references and drawing revisions, the criteria above completed from your specification, the responsible parties set against your own contract, the check-sheet numbering aligned — inspection item 4.12 on the ITP has to be item 4.12 on the check-sheet — and a named author, reviewer and approver.

So it says DRAFT — FOR COMPETENT REVIEW on its own title, and should keep saying it until a competent person has been through it against the specification.