Quantity take-off for curb backrests (concrete support behind curbs) and pricing by applying quota line items under Beijing DB11/T 2382-2024 (sub-items D2-3-44, D2-5-1, E-3-75)

Topic Positioning

This card explains the quantity take-off (measurement) basis for curb backrests (concrete support behind curbs) and the method of pricing by applying quota line items under Beijing's current consumption standard, for BOQ listing, quantity takeoff, and price assembly of curb backrests in municipal road and landscape works.

Core Conclusions

1. Quantity take-off (measurement)

1. Curb backrest (back-support concrete) is measured in m3 by volume: computed per design dimensions, i.e., design section area of the backrest x corresponding length, accumulated segment by segment.
2. Measured separately from the curb body: curb setting is measured in m along the design centerline; the backrest is an independent concrete element, listed separately in m3, and must not be merged into the curb-setting item.

2. Pricing by applying quota line items (Beijing DB11/T 2382-2024 Consumption Standard for Construction Works)

Use	Sub-item	Name	Unit
Municipal road: backrest concrete	D2-3-44	Concrete support behind curbs (Table D.2.11-6)	m3
Backrest formwork (if needed)	D2-5-1	Formwork, curb (Table D.2.18 formwork)	m2
Landscape: backrest concrete	E-3-75	Concrete support behind curbs (continuation of Table E.3.3-3 curbs, tree-pool edging)	m3

D2-3-44 consumptions (per m3): composite labor class II 0.9480 workdays; ready-mixed pea-gravel concrete C20 1.0100 m3; nylon cutting disc D100 1.5000%; 4 t water truck 0.0615 shifts; other tools 2.0000%. Work content: trenching, setting, pointing, curing, cleanup, etc.

E-3-75 consumptions identical to D2-3-44 (composite labor class II 0.9480 workdays, ready-mixed pea-gravel concrete C20 1.0100 m3, nylon disc D100 1.5000%, 4 t water truck 0.0615 shifts, other tools 2.0000%); work content: concrete placing, vibrating, curing, cleanup, etc.

D2-5-1 consumptions (per m2, by formwork contact area): composite labor class I 0.1690 workdays; lumber 0.0030 m3; composite steel forms 0.1250 m2-day; nails 0.2090 m, 0.1000 kg; nylon disc D100 5.0000%; 15 t truck 0.0011 shifts; 16 t truck crane 0.0011 shifts; other tools 2.0000%. Work content: on-site haulage, formwork fabrication, erection, release agent, stripping, repair, stacking, etc.

3. Common error D2-3-43 "cast-in-place concrete curb" (material: ready-mixed concrete C30) is the sub-item for the curb body itself, not the backrest; backrest concrete is priced by applying sub-item D2-3-44 (ready-mixed pea-gravel concrete C20) — do not mix them up.

4. Workmanship and acceptance requirements (verbatim)

• T/AACPM 002-2020 Clause 10.1.2: "Curb backrests should use cast-in-place C15 concrete; height and width shall be formed and cast per the design drawings; the height must not be reduced by widening, otherwise later replacement of planting soil in green belts is affected." "After casting, backfill promptly to protect; width preferably not less than 50 cm, height not less than 15 cm."
• BJJT 0047-2019 Clause 5.1.4: "The dimensions and strength of curb foundations and back concrete shall meet the design requirements."

Applicable Boundaries

• Region and version: sub-item numbers and consumptions are from Beijing's DB11/T 2382-2024 (Appendix D municipal: D2-3-44, D2-5-1; Appendix E landscape: E-3-75); other provinces/cities follow their local consumption quotas — numbers are not transferable across regions.
• Material conversion: D2-3-44 and E-3-75 are based on ready-mixed pea-gravel concrete C20; convert per quota rules where the design grade or material differs.
• Design prevails: backrest dimensions and strength follow the drawings (BJJT 0047-2019 Clause 5.1.4).
• Measurement basis: computed per design dimensions; the consumptions are the quantities embedded in the quota norms (loss included, e.g., ready-mixed concrete 1.0100 m3/m3); labor, material and machinery unit prices are adjusted separately at the compilation-period market prices or published price information (government guidance prices).

Further Reading

• DB11/T 2382-2024 Consumption Standard for Construction Works, Appendix D municipal works, Table D.2.11-6 "concrete support behind curbs" (sub-items D2-3-43, D2-3-44); Table D.2.18 "formwork" (sub-item D2-5-1 "formwork, curb").
• Same standard, Appendix E landscape works, E.3 garden roads and bridges, E.3.3-3 "curbs, tree-pool edging" and continuation (sub-item E-3-75).
• T/AACPM 002-2020 Guideline for Standardized Construction of Urban Roads and Ancillary Works, Chapter 10, Clause 10.1.2 (curb installation process, backrest casting, tolerance checks).
• BJJT 0047-2019 Specification for Construction Quality Acceptance of Granite Curbs, Clause 5.1.4.