Action > FibIISup
The actions FibIILc and FibIISup perform a fiber stress check for a cracked concrete section. In FibIISup it is possible to specify different envelopes for checking if the section is cracked (1st envelope) and for calculating the stresses in the cracked state (2nd envelope).
If any stress in uncracked concrete exceeds the tensile stress limit (stress limit I), a linear ultimate load check is started. This check uses a linear stress-strain curve (modulus of elasticity) within the input stress limit II. The tensile stress in concrete is set to zero. The number of the stress limit pair used for comparison of the actual stresses in order to detect stresses exceeding of the allowable level, is specified in Input2. A 2nd stress limit pair (maybe the same) must be specified for performing the equilibrium calculation in the cracked section (only the compression limit used, the tensile limit is always set to zero in this context). The pre-stressing load case must be specified if the relevant primary state is not included in the summation load case or considered envelope.
If the option Rein is set, a reinforcement design procedure will be performed if necessary, i.e. if no equilibrium can be achieved without additional reinforcement.