When analyzed from the mechanical perspective, the coupler scaffold system’s major stability issues come from the joints of the structure,

i.e. the joints between the standing tubes and the small and big flat tubes. And there are about three calculation ways for it.

The calculation of the joints rigidity. Suppose the joints of the flat tubes and the standing tubes are rigid kind and the whole scaffolding system is the

non lateral sway multi level steel frame. So this slipping calculation result is totally the same as the testing result. And the two have same rules to

follow. However, the calculation result number is much bigger than that of the testing result.

The rest calculation ways include the semi-rigidity joints calculation, the hinge connection calculation and the finite element calculation.