How to get stressfree length of cable?

E=210000MPa, D=25mm, system length = 3.5803m

The cable has initial strain load, no transverse load on it.

LC NO TYPE TITL
31 - Pre
CABL FROM TO TYPE PA
‘GRP’ 31 EX 1

I made a Form-finding analysis

After calculation, it shows N=173.7kN, Axial displacement dL = 0.256m, Relaxed cable length = 3.574m
Does stressfree length L0 = 3.574 - 0.256 = 3.318m?
But according to N=E * A * dL / L0,
L0 = 210000MPa * 0.25 * pi * (25mm)^2 * 0.256m / 173.7kN = 151.92m, it’s too large.

Hello

The relaxed cable lengths are shown in the SOFiSTiK Graphic.

Best regards
Frederik Höller
Your SOFiSTiK Support Team