design strength reality check

Short-Term to 50-Year Design Strength Reality Check

Enter any supplier’s published crush figure and watch it collapse once creep (long-term behaviour) and the CIRIA C737:2016 partial material factor are applied. This is an illustrative calculator for comparing catalogue claims — not a Storm Manage design value.

Inputs

Step 1

Supplier’s published short-term strength (kN/m²) Catalogue tonnages are short-term crush figures, not design values.

Step 2

Creep-reduced characteristic strength at 50 years (kN/m²) From a long-term BS EN 17151 programme; competing BBA-certified crates publish 121.2 and 137.5 kN/m².

Step 3

Partial material factor (γ_m) Values published in BBA certificates for competing PP crates, applied per CIRIA C737:2016.

Result

Design strength P_d

— kN/m²

Reduction from catalogue

—

Of catalogue figure retained

— %

Characteristic / γ_m

—

Short-term (catalogue)—

50-yr characteristic—

50-yr design P_d—

Worked reference rows

Published figures for competing BBA-certified PP crates (brands withheld) alongside Storm Manage’s honest position.

Crate	Short-term (kN/m²)	50-yr characteristic (kN/m²)	50-yr design P_d (kN/m²)	γ_m
Competing Crate A	363.0	121.2	72.4	1.67
Competing Crate B	438.8	137.5	76.0	1.81
Storm Manage SG-H60	600 †	not yet independently derived	not published	—

† 600 kN/m² was recorded without specimen failure over a 0.5 m² face (Intertek, third-party, ISO/IEC 17025 process, Report 190702149GZU-001). This is a short-term lower bound because the 300 kN loading cell reached capacity, not the module. Storm Manage holds no independently derived 50-year design strength; a 60-ton creep test record is released on request.

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