When we assign a Preload of 600kN/m to a Strut element at Stage 7, the program analyses and output a Strut load of 112kN/m only which is smaller than the Preload (600kN/m) at the same Stage !! Can you tell us how come the discrepancy between assigned Preload and the output Strut load?
The preload is merely a load that is applied to the strut before a Stage is analysed. The final strut load for that Stage will consider that preload, but adjust the load in the strut in order to maintain equilibrium in the model.