Calculation parameters

Defines the maximum numbers of steps, used to find the state of equilibrium in a section.

Defines the numerical precision in percentages.

This value is used in all checks for final assessment whether the member satisfies or does not satisfies the prescribed conditions.

Normally, this value will be one (1), but it can be even lower or greater than 1.

As,tot or 0 (As, tot for As,req > 0 and 0 for As,req = 0)

The total area of reinforcement is used for the calculation on condition that the design function has been already run and that the program has already calculated the required area of reinforcement. Otherwise, zero value is used (even if the user has manually inserted some reinforcement bars).

The total area of reinforcement is the sum of the user-defined reinforcement (through basic reinforcement, through reinforcement zones/regions or through free bars) and calculated additional required reinforcement. The additional required reinforcement may be zero, if the user has already inputted enough user-defined reinforcement.

IMPORTANT: Keep in mind, that the function calculating the required areas of reinforcement MUST HAVE BEEN run before. Otherwise, the user-defined reinforcement is ignored and ZERO value is used.

As, user

The user-defined reinforcement is used for the calculation. The term user-defined reinforcement covers the basic reinforcement specified in member data, reinforcement bars inputted through reinforcement templates in reinforcement zones (1D members) or regions (2D members), and free bars of reinforcement.

In order: [ As, user ]; [ As,tot or  0]

If there is any user-defined reinforcement, it is used, otherwise, the total reinforcement is used (which in fact means the calculated required area of reinforcement). Remember, that for the second option, the design function must have been already run.

In order: [ As,tot or  0]; [ As, user]

If the design of reinforcement has been already performed and the required area of reinforcement has been already calculated, it is used. Otherwise, the user-defined reinforcement is used.

The checks are performed only in selected sections. This option can dramatically speed up the program.

The area of reinforcement is subtracted from the area of the cross-section – as if ducts were installed.

If ON, the already inserted longitudinal reinforcement is taken into account during the calculation.

If ON, the torsion check is performed.

If ON, the shear stress in joints is checked.

If ON, the interaction of shear, torsion, flexure and axial load is checked.

The limit value of the ratio of compression zone of concrete to effective height of the cross-section.

This parameter can simplify the input for those users who calculate simple problems and need to adjust just a few basic parameters.

If ON, all the items in the column setup part are available.

If OFF, only the basic parameters are available. The less-common parameters are disabled.

The following cross-sections are supported: rectangular, L-section, T-section, I-section.

The bars are designed only in corners of the cross-section. The calculation is iterative and diameter or area of reinforcement in corner is increased until the check  is satisfied.

The user may determine that the design of reinforcement is carried out in the foot and head of the column. Otherwise, the calculation is carried out in all intermediate sections as well, which may be time consuming and bring no profit in terms of accuracy. The subsequent check of the designed reinforcement is performed in all sections.

The option activates a pseudo-linear calculation of buckling for 1D member (the genuine 2nd order analysis is the non-linear one, i.e. using the Timoshenko or Newton-Raphson iteration). If this option is ON, a special algorithm is started on the background that evaluates bar imperfections and 1st + 2nd order deflections which leads to an approximation of the 1st order bending moments by increased 2nd order moments.

DIN 1045-1 introduces for this situation the concept of "Model column method" and ÖNORM calls it "Spare bar method". Each national standard implemented in SCIA Engineer uses its analysis path that takes into account the stipulations of the particular standard.

The user’s estimate of reinforcement ratio for columns. When the reinforcement is being designed with the effect of buckling length taken into account, the area of reinforcement is known yet. This are is, therefore, calculated using the user-specified value in this item.

If ON, the number of bars in the cross-section is optimised to achieve the minimum number of bars with the cross-section still passing the check.

The largest of bending moments My, Mz will be taken into consideration. The smaller one will be ignored.

Both My and Mz are taken into account. The design is carried out using interaction formula

(My/Myu)x + (Mz/Mzu)x < 1

where x is the safety factor (see below).

If the ratio of one bending moment to the other along the whole beam length is smaller than the input value, then the beam is considered to be subject to uni-axial bending. Otherwise, if at least one cross-section is found where the ratio is greater than the input value, the biaxial approach is applied.

Specifies the safety factor used in the interaction formula above.

Default value = 1.4.

real area of reinforcement

If this option is ON, the reinforcement is calculated from the real sectional area of individual bars.

delta area of reinforcement

If this option is ON, the reinforcement is calculated using the user defined area (delta).

If the option is ON, the number on bars in section is minimised so that their minimal number is used.

automatic

If ON, the ratio of y-reinforcement to z-reinforcement is determined automatically.

manual

If ON, the user specifies the ratio of reinforcement in y-direction to reinforcement in z-direction.

If ON, activates the check of the limit value of the depth of compression zone x_lim (full value of tensile strength of steel is reached)

If the compression reinforcement is necessary, check this box to provide for its calculation.

If ON the normal force in beam is takes into account.

Bending moment diagram may be "shifted" in supports in order to provide for reduction of support bending moments. The reduction depends on the type of support. For supports of Column type, the support dimension is calculated from the column’s cross-section. For standard supports the user must input the support size (see the chapter dealing with point supports in the main reference manual).

If reduction of shear force in supports is allowed, check this box.

at the face (support/column)

the reduced shear force is determined at the support face

at the effective depth from the face (support/column)

the reduced shear force is determined in the effective length from the support face

If ON, the statically required shear reinforcement in cross-sections with depth < 200 mm is declared as non-designable.

EN 1992-1-1:2004: art. 9.3.2(1)

If ON, construction reinforcement for deep beams will be taken into account.

Shells:

If the real eccentricity in cross-section is greater than the value on input, the state of stress-strain is considered as "prevailing bending", otherwise "prevailing normal force". This parameter is used in the control of minimum pressure reinforcement.

Compare ÖNORM B 4700: art. 3.4.2(3)

Default value = 2.0

Definition of the relative height of the bending pressure zone for different concrete strengths

According to EN 1992-1-1: art. 2.5.3.4(5)

Definition of the limit value ksi=x/d for concrete classes up to C35/45.

According to EN 1992-1-1: art. 2.5.3.4.2(5)

Default value = 0.45

Definition of the limit value ksi=x/d for concrete classes higher than C35/45.

According to EN 1992-1-1 art. 2.5.3.4.2(5)

Default value = 0.35