Norm items and measurement for shear-wall concealed columns, concealed beams, and coupling beams (Beijing DB11/T 2382-2024: concealed members merge into the wall; shear walls route by section height-to-thickness ratio into short-leg walls/columns/straight walls)

Topic Positioning

Which items to apply for concealed columns, concealed beams, and coupling beams in shear-wall structures, where their quantities merge, and the routing between ordinary and short-leg shear walls. Per Beijing DB11/T 2382-2024 Section 4.6 (concrete and reinforced concrete), with GB/T 50861-2024 comparisons.

Core Conclusions

1. Concealed columns/beams: merge into the wall, apply wall items. DB11/T 2382-2024, 4.6.1(2): "In reinforced concrete structures, beams, slabs, columns, and walls execute their respective items; concealed beams and columns integral with the wall execute wall items; decorative bands projecting from walls execute wall items; those projecting from beams execute beam items." No separate column/beam items; quantities merge per 4.6.6(5) "wall piers and projections merge into wall volume".

2. Classify shear walls before applying items. 4.6.1(5): "Shear walls with thickness <= 300mm and maximum limb height/thickness ratio > 4 and <= 8 execute short-leg wall items; with maximum ratio <= 4, column items may apply." Others execute straight-wall and related wall items.

3. Coupling beams. Beijing's text has no "coupling beam" entry; coupling beams cast integrally with wall limbs, usually wall-thick, are handled as "integral with the wall" — merged into the wall, wall items, no separate beam items. Comparison: GB/T 50861-2024 Annex C.8.4 "wall piers (attached columns), concealed columns/beams and projections merge into wall volume" "where slab and wall overlap, count as wall; where beam and wall overlap, count as beam".

4. Measurement interfaces (4.6.6). Wall length: external walls by centerline, internal by net; wall height: with slabs, from foundation (grade beams) or slab top to the next slab top; with beams, to the beam soffit; parapets from roof slab top to parapet top, coping/strings/decorative bands merging in. Beams: length to the wall face where connected.

5. Straight-wall item reference. Item A-5-24 "straight wall", unit m3, work: pouring, vibrating, curing; consumption: labor class II 0.3280 workdays/m3, ready-mix C30 0.9950 m3/m3, same-grade mortar (comprehensive) 0.0150 m3/m3, other materials 1.5%, other machinery 2.0%. Budgeting note: work covers pouring/vibrating/curing only; Beijing prices concrete and formwork separately — formwork goes under measures, neither omitted nor duplicated.

Applicable Boundaries

• Applies to building works priced under Beijing DB11/T 2382-2024; other regions follow local standards (some merge wall/column/beam items with different calibers).
• "Merge into wall" presumes the member is integral with and cast against the wall; independent columns/beams take their own items. Coupling beams projecting beyond the wall face follow the 4.6.6 interface rules (beam to wall face; wall to beam soffit).
• Short-leg wall determination requires per-limb section checks per the drawings.
• GB/T 50861-2024 is the rail transit measurement standard — cited for comparison only.
• Contracts, tender documents, and local interpretations govern.

Further Reading

• DB11/T 2382-2024, 4.6.1 (cast member setup), 4.6.6 (cast concrete measurement), Annex A.5 items (straight wall A-5-24 onward).
• GB/T 50861-2024 Annex C.8.4 (underground structures: concealed members merge into wall volume).
• Measures section formwork provisions (Beijing prices concrete and formwork separately).