Dosage design - Theoretical background

 

The fibre dosage design is iterative procedure which calculates the resistance of cross-section with current fibre dosage and standard reinforcement and compare it with acting load to get equilibrium of forces. The main task is the calculation of moment resistance of cross-section. For more details about this procedure, see "Capacity Check Theoretical background". It is one iterative step with defined fibre dosage.

The calculation precognitions for finding plane of equilibrium of steel fibre concrete with reinforcement are taken from Figure R.4 - Determining stresses and strains for steel fibre reinforced concrete from [1] DAfStb Guideline "Steel fibre reinforced concrete"

The iterative procedure start with maximal allowed dosage design (35kg/m³), defined by type of fibres, see "Fibre library". The verification if 2D element is able to resist the acting load with existing reinforcement is performed. If yes, than procedure calculate the resistance for minimal allowed dosage design and if the equilibrium is not found, than iterative algorithm based on bisection method start to find the optimal dosage.

Maximal dosage exceeded

If maximal dosage is not enough to get equilibrium of forces, than it is necessary to increase amount of standard reinforcement, or to increase quality of concrete, or to increase the thickness of 2D element.