Ground beams

Longrines (ground beams): what the project manager needs to know about these linear foundations to avoid confusing two structurally different elements — and approving a pour with no inspection-body check

"The reinforcement cages for the ground beams are in place. Pouring of the ground beams carried out following today's site visit." A single sentence in the Foundations section. If you haven't checked that the inspection body actually examined the reinforcement before this pour, it's too late.

1. Operational definition + common mistake

Longrines ("ground beams") are linear reinforced-concrete foundation elements that connect isolated point foundations (footings) to each other, or that form a continuous load-bearing frame at the base of a structure. They play an essential role in transferring vertical loads to the ground and in horizontally tying the structure together, particularly to limit differential settlement.

In this CR, the ground beams form the main foundation of the renovation extension. The process is described: reinforcement in a rebar cage → site visit (inspection-body and MOE check) → pour. This sequence is critical: ground beams can only be poured after inspection and, where required, sign-off by the inspection body.

Many assume ground beams are simply "strip footings" — in reality, strip footings directly support load-bearing walls at surface level, while ground beams are connecting and tying elements between point foundations, with a distinct structural logic and design.

2. Where it appears

In a site meeting report — in the Foundations or Shell-and-Structure section, during the early phases of structural execution. In this CR:

"The reinforcement cages for the ground beams are in place."
"Pouring of the ground beams: carried out following today's site visit."

3. How to read this entry in the CR

If you read "ground-beam reinforcement in place" → this is the signal of a potential checkpoint. Check whether the inspection body needs to approve the reinforcement before the pour. If so, schedule the visit before letting the contractor pour.

If you read "ground beams poured" → check that the inspection body's verification visit actually took place beforehand, and that the sign-off has been obtained. If not, document it and take corrective steps.

4. Who does what

5. What this changes in practice

A project manager who schedules the verification visit before every foundation pour can ensure the reinforcement is compliant. A project manager who discovers after the fact that ground beams were poured with no inspection-body visit can no longer verify the reinforcement's compliance: the structure is closed.

Failure scenario: the ground beams are poured on a Friday afternoon while the inspection-body visit scheduled for Monday hasn't taken place yet. If a structural defect later occurs, the absence of a sign-off before pouring weakens the entire chain of liability.

6. Example of real wording

"The reinforcement cages for the ground beams are in place."
"Pouring of the ground beams: carried out following today's site visit."

7. Points of caution

• A ground beam cannot be poured without the reinforcement being checked by the inspection body (if their assignment covers it).

• Ground beams are buried elements: once poured, verification is impossible without demolition.

• The ground-beam reinforcement drawing is a document subject to MOE and inspection-body sign-off — check it's actually approved before installation.

• On projects subject to DO insurance and inspection-body oversight, ground-beam records and certificates are part of the as-built file (DOE).

• Don't confuse ground beams with horizontal tie-beams higher up in walls.

8. Not to be confused with

9. Related terms

Same phase (foundations): Strip footing · Raft foundation · Reinforcement · Pouring · Formwork · Inspection-body visit

Same actor (contractor/inspection body/structural engineer): Structural drawings · Sign-off (visa) · DOE · Checkpoint