Thrust Block Calculator

Compute the external thrust at plugs, tees and bends, verify block stability against passive earth pressure and base friction (K·R ≤ T), and print a trilingual (EN/FR/ZH) design calc sheet modeled on a real approved project document.

Disclaimer：Results are produced by deterministic formulas and are intended for quantity estimating and option comparison only. A qualified engineer must verify them against the project specification, design documents and actual site conditions before use. The author accepts no liability for any loss arising from their use.

Calc sheet — printable (ZH / EN / FR)

Thrust block design table — editable sizes with live stability check (K·R ≤ T)

Safety factor K K = 1.5

When you edit one dimension, the dimensions you have not touched are auto-set to their minimum required value; dimensions you set yourself are kept as entered — rows that still fail K·R ≤ T are highlighted in red (Reset restores the recommended sizes).

Fitting	DN	Thrust R (N)	Block dimensions (m) · editable			Concrete V (m³)	Resistance T (N)	K·R−T (N)	Check
Fitting	DN	Thrust R (N)	L (m)	H (m)	E (m)	Concrete V (m³)	Resistance T (N)	K·R−T (N)	Check
Blank end (plug)	DN63	902.55				0.001	1488.0	-134.2	✓ OK
	DN90	1841.94				0.003	3436.7	-673.8	✓ OK
	DN110	2751.54				0.008	6267.2	-2139.9	✓ OK
	DN160	5821.44				0.015	10038.7	-1306.6	✓ OK
	DN225	11512.12				0.040	20640.9	-3372.7	✓ OK
Tee	DN63	902.55				0.001	1488.0	-134.2	✓ OK
	DN90	1841.94				0.003	3436.7	-673.8	✓ OK
	DN110	2751.54				0.008	6267.2	-2139.9	✓ OK
	DN160	5821.44				0.015	10038.7	-1306.6	✓ OK
	DN225	11512.12				0.040	20640.9	-3372.7	✓ OK
45° bend	DN63	690.78				0.001	1488.0	-451.9	✓ OK
	DN90	1409.76				0.003	3436.7	-1322.1	✓ OK
	DN110	2105.94				0.003	3436.7	-277.8	✓ OK
	DN160	4455.54				0.015	10038.7	-3355.4	✓ OK
	DN225	8811.00				0.026	14810.2	-1593.7	✓ OK
90° bend	DN63	1276.40				0.003	3436.7	-1522.1	✓ OK
	DN90	2604.90				0.008	6267.2	-2359.9	✓ OK
	DN110	3891.27				0.008	6267.2	-430.3	✓ OK
	DN160	8232.76				0.026	14810.2	-2461.1	✓ OK
	DN225	16280.60				0.060	27589.7	-3168.8	✓ OK

Initial values are theoretical optima (minimum cube block, rounded up to 5 cm) — adjust freely; rows marked red do not satisfy K·R ≤ T.

Parameters are inherited live from the calculator inputs above (any change recomputes the whole table): test pressure P₀ = 1.2 N/mm², joint factor k = 0.9, Pₛ = 1 N/mm²; φ = 49°, γ = 19.7 kN/m³, base friction f = 0.4 (soil class: sand); depth to block top h₁ = 1 m; C15 block γc = 22 kN/m³. T1 uses the degree-based (correct) tangent. Concrete volume deducts the pipe occupancy (1/18).

This table is printed/exported together with the calc sheet above as one report.

ASSUMPTIONS

RESULT

CALCULATION

Calc sheet — printable (ZH / EN / FR)

As-built thrust block sizes — Kinshasa water project (K = 1.1, project sheet)

Fitting	DN	R (N)	L (m)	H (m)	E (m)	T (N)	K·R−T (N)
Blank end (plug)	DN63	902.55	0.40	0.35	0.40	997.44	-4.63
Blank end (plug)	DN90	1841.94	0.64	0.36	0.60	2028.20	-2.06
Blank end (plug)	DN110	2751.54	0.63	0.53	0.60	3031.09	-4.39
Blank end (plug)	DN160	5821.44	0.82	0.70	0.82	6418.00	-14.41
Blank end (plug)	DN225	11512.13	1.00	0.97	1.00	12720.37	-57.03
Tee	DN63	902.55	0.40	0.35	0.40	997.44	-4.63
Tee	DN90	1841.94	0.64	0.36	0.60	2028.20	-2.06
Tee	DN110	2751.54	0.63	0.53	0.60	3031.09	-4.39
Tee	DN160	5821.44	0.82	0.70	0.82	6418.00	-14.41
Tee	DN225	11512.13	1.00	0.97	1.00	12720.37	-57.03
90° bend	DN63	1276.40	0.45	0.41	0.45	1409.05	-5.01
90° bend	DN90	2604.90	0.60	0.53	0.60	2886.75	-21.36
90° bend	DN110	3891.27	0.75	0.56	0.73	4286.85	-6.46
90° bend	DN160	8232.76	0.90	0.84	0.89	9063.94	-7.91
90° bend	DN225	16280.60	1.21	1.00	1.20	17937.67	-29.00
45° bend	DN63	690.78	0.35	0.33	0.34	761.55	-1.69
45° bend	DN90	1409.76	0.48	0.42	0.46	1559.66	-8.92
45° bend	DN110	2105.94	0.53	0.53	0.50	2318.84	-2.31
45° bend	DN160	4455.54	0.72	0.66	0.73	4927.11	-26.02
45° bend	DN225	8811.00	0.89	0.90	0.90	9747.75	-55.65

METHOD

Deterministic pipeline: P = 0.758·D²·(P₀−k·Pₛ) (bore estimated as 0.983·D, matching the project sheet) → R = P or 2P·sin(α/2) → T₁ = ½·tg²(45°+φ/2)·γ·(h₂²−h₁²)·l → T₂ = G·f (pipe occupancy 1/18 deducted) → verdict K·R − T ≤ 0. Every rendered number comes from these formulas — no AI text. The calc sheet reproduces the structure of the approved Kinshasa project document; figures are kept from the source textbook with translated captions only.

Formula system: 「支墩设计计算」(Thrust block design), C15 plain-concrete block; external thrust P = 0.785·Di²·(Po − k·Ps) with the pipe bore taken as 0.983·D (project convention 0.758·D²), resistance from passive earth pressure plus base friction, verified as K·R ≤ T = T1 + T2.
Friction coefficients f per Table 2-1 of the source document (sand 0.40, gravel 0.40–0.50, stiff clay 0.30–0.40, plastic clay 0.25). Internal friction angle φ must come from the geotechnical report; sand ≈ 48–49° per the project reference.
Default dimensions prefill the as-built table of the Kinshasa water supply project (K = 1.1). That table was computed with TAN(45+49/2) evaluated in radians (≈ tan 0.385 rad), i.e. a far smaller soil term than the degree-based textbook formula — the as-built blocks are therefore conservative. This tool computes T1 correctly in degrees.

Engineering Translation

Working across languages on tenders, specs and technical clauses? EngTranslate gives you domain-trained Chinese ⇄ English translation, a construction & BIM terminology base, and metric–imperial unit handling in one place. EngTranslate →

Thrust Block Calculator

INPUT

Calc sheet — printable (ZH / EN / FR)

Thrust block design table — editable sizes with live stability check (K·R ≤ T)

ASSUMPTIONS

RESULT

CALCULATION

Calc sheet — printable (ZH / EN / FR)

As-built thrust block sizes — Kinshasa water project (K = 1.1, project sheet)

METHOD

Engineering Translation