ISO Standard 1496(1) states that the corner posts of ISO Series 1 containers should be tested to a load of 86,400 kg (190,480 lbs).

Corner post steels typically correspond to the specification ASTM A-572, with a yield stress of 47,000 psi, and an ultimate stress of 70,000 psi.

Corner posts will yield at a stress of 47,000psi. Therefore, the minimum cross sectional area for resisting the corner post loads is A =190,840/47,000 = 4.05 in2. The maximum load which a single corner fitting must take is then Ptot = 190,480 + (52,800/4) = 203,680 lbs.

Corner fittings are typically cast and machined from A-216 steel, which has a minimum specified yield stress of 40,000 psi. The ISO Standard, however, does not define a force Fcp-fail; rather, it specifies the load that each corner post must withstand without failure. In this sense, the specified load is a proof load, Fcp_proof, which is simply a load which each corner post must be shown capable of resisting.

Racking test load value = 33,600 lbs

End wall strength =12,460 lbs

CORETEN STEEL is usually ASTM grade A 588 Transverse rigidity - Ability to withstand transverse racking forces as ship rolls to 30 degrees. A test value of 150 kN used assuming a 40' container with an average gross mass of 25,000 kg (55,000 lbs).

Longitudinal rigidity - Ability to withstand longitudinal racking forces as ships pitch to an angle of 15 degrees. A loaded container is restrained at the bottom; a 75 Kn longitudinal force is applied to each top corner fitting, while deflections are measured.