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4.1 Concrete setup for 1D member

This setup is available from tree Concrete > 1D member > Setup. After clicking on this item the dialog in the picture below is opened

The global setting is divided to the following sheets:

• Design default
• General
• General > Calculation
• Design strength
• Interaction diagram
• Shear
• Detailing provisions
• Warnings and errors

Blue coloured parameters might be changed for each member by using local setting (Member data).

Concrete setup can be opened too via action button Concrete setup or via Code setup in the single check

4.1.1 Design default

This group is divided into three main parts. It is possible to define minimal concrete cover, set default values for member design, such as reinforcement diameters, and materials both independent for main reinforcement and stirrups. It is also possible to define sway type here.

4.1.1.1 Group general

4.1.1.1.1 Minimal concrete cover

User may choose from two possibilities to determine concrete cover:

4.1.1.1.1.1 User defined concrete cover

By selecting this possibility, program will enable edit boxes for concrete cover, both for upper and lower surface, and user defines his own value to be used.

4.1.1.1.1.2 Use min concrete cover

By this possibility, user let SCIA Engineer to evaluate minimum concrete cover, which may be used according to the Code. Parameters used for this evaluation may be defined in Concrete cover dialog, which is shown below. Here user may redefine type of concrete cover, situation and some more addition to the value due to the corrosive environments.

4.1.1.2 Reinforcement

Default value of reinforcement and stirrup diameters together with default material used are to be defined here. User may define default settings separately for beams, columns and beam slabs members, in each of three folders. Design defaults for Beams are shown on the first picture of this chapter. In 2D concrete setup dialog, different folders will be displayed. They are named Plates, Walls and Shells. Values from Plates folder are the similar to those, which are stored in Beam slabs folder in 1D concrete setup.

4.1.1.3 Sway type

This is option for calculation of slenderness and internal forces in 1D members. If the check box is active, it indicates that members are prone to sway from the respective axis. This setting has least priority when compared to Buckling data library and Buckling data set for the member.

4.1.2 General

Here user may check or even adjust important design material characteristics of concrete and non-prestressed reinforcement steel.

4.1.2.1 Tab sheet Concrete

4.1.2.1.1 Minimum value of fc’

The value sets minimum value of compression strength of concrete. According to the Code, concrete shall be proportioned to provide an average compressive strength, fcr  and shall satisfy the durability criteria. For concrete designed and constructed in accordance with the Code, fc′ shall not be less than 17 Mpa = 2500 psi.

4.1.2.1.2 Maximum value of fc’

The value sets maximum value of compression strength of concrete. Because of a lack of test data and practical experience with concretes having compressive strengths greater than 70 MPa, the Code imposed a maximum value of 8.3 MPa on √fc’ for use in the calculation of shear strength of concrete beams, joists, and slabs. Exceptions to this limit were permitted in 11.1.2.1.

4.1.2.1.3 Coefficient for specified compressive strength

This coefficient reduces concrete compression strength. According to the Code, concrete stress of 0.85fc′ shall be assumed uniformly distributed over an equivalent compression zone bounded by edges of the cross section and a straight line located parallel to the neutral axis.

4.1.2.2 Tab sheet Non-prestressed reinforcement

4.1.2.2.1 Maximum value of fy

Here the maximum design strength of non-prestressed reinforcement is defined. Code defines maximum of the values of fy and fyt , used in design calculations, shall not exceed 550 MPa, except for prestressing steel and for spiral transverse reinforcement in 10.9.3.

Minimum and maximum value of fc’ together with maximum value of fy are also limit values for concrete and reinforcement steel material parameters. It is not possible to input appropriate values in material properties. If so, en error message will be displayed.

4.1.3 General > Calculation

The user can set general parameters for calculation of 1D member and special parameters for calculation and design reinforcement for beams and column.

4.1.3.1 Group General

There is possible to define parameters, which will be used for beams and columns

4.1.3.1.1 Number of iteration steps

This setting is used for iterative calculation in concrete. If iterative calculation does not finish after reaching number of steps, the calculation is finished. In this case, the result will not be presented and user has to make some changes in calculated structures or decrease precision of iteration (see chapter "4.1 Concrete setup for 1D member") or increase number of iteration steps.

4.1.3.1.2 Precision of iteration

This setting is used for iterative calculation in concrete. Iterative calculation is finished if difference of results of two consecutive iteration steps is lesser than this precision. If iterative calculation does not finish after reaching number of steps, the calculation is finished. In this case, the result will not be presented and user has to:

• make some changes in calculated structures or
• or decrease precision of iteration
• or increase number of iteration steps (see chapter "4.1 Concrete setup for 1D member")

4.1.3.1.3 Check selected section only

If this check box is ON, then the results are calculated and presented only at the ends of the member and in user defined sections. It follows, that calculation is much faster. The user sections can be defined in tree Structure > Model data > Section on beam

There is comparison of results if this setting is ON/OFF and some user sections are defined (in thirds of member length)

4.1.3.1.4 Use iterative calculation for design reinforcement

Design strength of the structure is calculated multiplying the nominal strength by a strength reduction factor  φ. This factor depends on the strain in tensile reinforcement, but this strain is unknown before design reinforcement. It follows, that for calculation of this value:

• strength reduction factor  will be estimated
• iterative calculation for strength reduction factor will be used

If this check box Use iterative calculation for design of reinforcement is OFF, then strength reduction factor loaded from concrete setup (see chapters ) will be used. It means that:

• for beams is used  strength reduction factor for tension-controlled section (see chapter )
• for column in tension (Nu ≥ 0) is used  strength reduction factor for tension-controlled section (see chapter )
• for column in tension (Nu < 0) is used  strength reduction factor for tension-controlled section (see chapter )

Else if this check box is ON, then iterative calculation for strength reduction factor will be used for design reinforcement to beam ("8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)") and for column ("8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)")

There is comparison of results if this setting is ON/OFF for simply supported beam.

If concrete member data are defined on the member and Type of strength reduction factor Phi = User input, then this check box has not influence to calculation strength reduction factor , because strength reduction factor is directly loaded from concrete member data

4.1.3.1.5 Columns

4.1.3.1.5.1 Advanced setting

If this check box is ON, there are only basic parameters in tab-sheet Column , which can be edit. After switching ON this check box Advanced setting, there are much more parameters for setting calculation of the columns.

4.1.3.1.5.2 Corner design only

Corner design only is special type of calculation, where the reinforcement is designed only in corner of cross-section with internal angle 90 deg. It is an iterative calculation, where number of bars is same, but the diameter of bars increases. This parameter has influence only for basic concrete cross-section, see table below.

This type of calculation is supported only for basic concrete cross-section (see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)"), for other type of cross-section calculation finished with error 683 (The design of main reinforcement area for the column is not supported for this type of cross-section)

There is comparison of design reinforcement with using method Only corner design for rectangular column with different value of internal forces.

4.1.3.1.5.3 Use buckling data

This setting allows taking into account second order eccentricity (magnified moments calculated according to clause 10.12 and 10.13 in ACI 315-05, see chapter "7.2 Internal forces for 1D members (beam, beam as slab, column)". The second order eccentricity in direction of local axis will be taken into account only if slenderness of the column in this direction is greater than limit slenderness and this check box is ON.

The detailed information about calculation of these magnified moments are presented in numerical output in the service Internal forces (tree Concrete >1D member), if the value My,recalc or Mz, recalc is selected.

4.1.3.1.5.4 Optimize the number of bars in c-s for biaxial calculation

The design reinforcement with using biaxial methods depends on value Ratio y/z (ratio of reinforcement in direction of y and z of LCS),see chapter . If this check box is ON, then the biaxial method is independent on value Ratio y/z and program tries to find the best arrangement of bars in cross-section with the minimum number of bars. It is iterative calculation, where program checked all possible arrangements of bars of reinforcement according to interaction formula ( see chapter "4.1 Concrete setup for 1D member") and select this one, which result of interaction formula is the nearest to one.

This setting has influence to speed of calculation, because if the check box is ON, iterative calculation is used and therefore the speed of calculation is slower, but the  result of design in many cases is better, see table below.

There is comparison of results if this setting is ON/OFF for column with the same load, but with different size of diameter of longitudinal reinforcement.

4.1.3.1.5.5 User estimate of reinf. for design of reinforcement

There are some values in design of reinforcement, which are dependent on area of reinforcement, for example:

• moment of inertia of reinforcement about centroidal axis of member cross section (I_se) in calculation of stiffness’s for critical buckling load (clause 10.12.3 (formula 10-11) in ACI 315-05)

These values should be calculated before design of reinforcement, but before design we do not know area of reinforcement. It follows that for calculation of this value

• area of reinforcement will be neglected,
• iterative calculation will be used or ,
• area of reinforcement will be estimated.

The third solution is implemented in SEN via edit box User estimate of reinf. for design of reinforcement, where user can set ratio of reinforcement, which will be used for calculation of the values above. The calculation moment of inertia of reinforcement depends on type of method and shape of concrete cross-section too. There are the following methods for calculation the radius of gyration of the total reinforcement:

• for design of reinforcement according to method Only corner design (Type of check = Design ULS in service Internal forces) the moment of inertia of reinforcement is calculated according to following steps:

• total area of reinforcement

                A_s = Ratio_lon ⋅A_c

• area of reinforcement of one bar

              A_1si = A_s/n_s

• second moment of reinforcement area o

• for design of reinforcement according to other methods and for rectangular section (Type of check = Design ULS in service Internal forces) the moment of inertia of reinforcement is calculated according to following steps:

• total area of reinforcement

A_s = Ratio_lon ⋅A_c

• calculation of ratio of reinforcement in y and z direction

      ,  

if  σ_y = 0 MPa and  σ_z = 0 MPa , then  ratio_y = ratio_z = 0,5 

• area of reinforcement in direction of y(z) axis of LCS

A_s,y(z) = ratio_y(z)⋅A_s

• second moment of reinforcement area

• for design of reinforcement for circular section (Type of check = Design ULS in service Internal forces) the moment of inertia of reinforcement is calculated according to following steps:

• total area of reinforcement

A_s = Ratio_lon ⋅A_c

• second moment of reinforcement area

If required designed area is lesser than 80% of estimated area setting in concrete setup or concrete member data and Equation for calculation EI for critical load Pc = 10-11(see chapter ), program gives warning 270 (The percentage of additional reinforcement is lesser than 80% of user estimate ratio). In this case, the value of user estimate ratio in concrete setup (if member data is not defined) or in concrete  member data (if it is defined) should be decreased.

If required designed area is greater than 120% of estimated area setting in concrete setup or concrete member data and Equation for calculation EI for critical load Pc = 10-11(see chapter ), program gives warning 271 (The percentage of additional reinforcement is greater than 120% of user estimate ratio). In this case, the value of user estimate ratio in concrete setup (if member data is not defined) or in concrete  member data (if it is defined) should be increased.

There is design of reinforcement for rectangular columns with different load and with different area of reinforcement column with.

4.1.3.1.5.6 Group Calculation method

There are supported only following cross-section for design reinforcement to column in SEN:

• Rectangular - 4 methods for design reinforcement to column with the rectangular cross-section are supported

• Uniaxial bending calculation (sum), mark US, see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)"
• Uniaxial bending calculation (max), mark UM, see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)"
• Biaxial bending calculation, mark B ,see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)"
• Automatic determination, mark UM or B, see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)"

Type of method can be selected by user via radio buttons, see picture below

• Circular - biaxial bending calculation is always used for this type of cross-section, see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)"
• T,I,L shape -  Only corner design is supported for these types of cross-sections, see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)"

4.1.3.1.5.6.1 Uniaxial bending calculation if ratio of biaxial moments is less than

Type of method, which will be used for design reinforcement, if Calculation Method =Automatic determination is selected, depends on ratio bending moments.

                                    Ratio(M_y/Mz) =

If this ratio is lesser than limit value set in this edit box, then for design of reinforcement in the section of the column Uniaxial bending calculation (max) will be used. Otherwise the Biaxial bending calculation will be used for design of reinforcement

This edit box is active only in the case, if in the combo box Type of calculation method item Automatic determination is selected

There is comparison of results for automatic determination type of method for design of reinforcement for column with different value of bending moment.

If bending moments in both direction are zero, then reinforcement is designed only for normal force and calculation type =N/A

4.1.3.1.5.6.2 Type of biaxial method

Biaxial method is iterative calculation, where the bars of reinforcement are added to cross-section depending on ratio y/z (see chapter "4.1 Concrete setup for 1D member") or number of bars is optimized (see chapter "4.1 Concrete setup for 1D member") as long as interaction formula is not fulfilled.

There are supported three types of method for biaxial calculation:

• Bressler reciprocal load method - this method approximates the ordinate 1/P_n on the reciprocal failure surface. The following interaction formula is used for this method:

• Bressler load contour method - in this method, the failure surface is approximated by a family of curves corresponding to constant values of nominal axial strength of the cross-section (P_n), it means the following interaction formula is used

• PCA load contour method – this method was developed as an extension of the Bresler Load Contour Method. In this method failure point is defined such that the factored biaxial moment M_uy and M_uz at this point are in the same ratio as the uniaxial moment resistance M_noy and M_noz. The same interaction formula is used as for Bressler load contour method, but  exponent of interaction formula (α) is calculated according to formula:

The combo box for selection type of biaxial method is active only if  Calculation method = Biaxial or Automatic determination

4.1.3.1.5.7 Group Design reinforcement using (biaxial and only corner design)

There are two basic properties in this group:

• Area of reinforcement type
• Delta area of reinforcement

4.1.3.1.5.7.1 Area of reinforcement type

This setting allows to set type of area of reinforcement for biaxial and only corner design, which will be used for design of reinforcement.  There are two possibilities:

• Real area of reinforcement bar – the diameter which is set in global setting (Concrete setup (Design default) of local setting (Member data) will be used for design. It means, that area of real bars will add to cross-section. The resultant area of reinforcement is multiple of area of defined reinforcement in local or global setting.

• Delta are of reinforcement – the area of reinforcement set in edit box Delta area of reinforcement  will add to cross-section instead of area real bars. It means, that resultant area of reinforcement is multiple of value  Delta are of reinforcement, but number of bars is calculated for diameter of bars sets set in global setting (Concrete setup (Design default) of local setting (Member data). Use this option allows to make the more economical design of reinforcement, but it depends on value Delta area of reinforcement.

        The comparison of results for different reinforcement type and different delta are of reinforcement for columns with different size number of reinforcement is in table below.

4.1.3.1.5.7.2 Delta area of reinforcement

This edit box is used for inputting area of reinforcement, which will be used for biaxial and only corner design. It is active only, if item Delta area of reinforcement is selected from combo box Area of reinforcement type.

4.1.3.1.5.8 Group Interaction formula and exponents

In this group are described interaction formulas for biaxial bending calculation and user can set exponent for interaction formula

4.1.3.1.5.8.1 Alpha

       Exponent of interaction formula for Bressler load contour method can be inputted via this paramet, see chapter see chapter "4.1 Concrete setup for 1D member". If exponent of interaction formula (value Alpha ) is 1,0, then Bressler load contour method can be used only for design reinforcement to column , where the following conditions is fulfilled

                   If value Alpha =1 and conditions above is not fulfilled, then program finishes with errors 854 (Bresler load contour method cannot be used, because Pu > 0,1*fc*Ag*Phi. Use different value Alpha or different method)

4.1.3.1.5.8.2 Beta

       Exponent of interaction formula for PCA load contour method can be inputted via this parameter, see chapter "4.1 Concrete setup for 1D member"

4.1.3.1.5.9 Group Ratio y/z

The one of the most important parameter for biaxial bending calculation is ratio of reinforcement in  y and z direction. There are three parameters which have influence to the ratio of the reinforcement

• Ratio type
• Ratio y/z
• Limit stress ratio

4.1.3.1.5.9.1 Ratio type

There are three possibilities for calculation ratio of reinforcement in biaxial bending calculation:

• Automatic - The value ratio y/z is calculated automatically as ratio of bending stresses in both direction

     Ratio y/z = if  σ_y = 0 MPa and  σ_z = 0 MPa , then  ratio_y/z = 1 

where
σ y	The bending stress around y-axis, σy = Muy/Wc,B,y
σz	The bending stress around y-axis, σz = Muz/Wc,B,z
Muy(z)	Factored (magnified) moment at section about  the y (z) axis of LCS of the member
Wc,B,y(z)	Section modulus for biaxial calculation around y (z) axis calculated concrete cross-section without concrete cover
b,h	dimension of rectangular cross-section
c	Concrete cover of the stirrup

• Manual – the ratio of reinforcement is directly input by user via parameter Ratio y/z. The user inputs only ratio of reinforcement in y direction and the ratio y/z is calculated according to formula

• From user reinforcement – the ratio of reinforcement is calculated as ratio of defined user reinforcement in y and z direction.

4.1.3.1.5.9.2 Ratio y/z

This edit box allows to input user value of ratio y/z. The ratio of reinforcement in y direction is inputted and the ratio in z direction is calculated by the program. This property is active, only  if Ratio type = Manual

4.1.3.1.5.9.3 Limit stress ratio

Design reinforcement with using biaxial bending calculation depends on value ratio y/z (ratio of reinforcement in y/z ), if check box Optimize the number of bars in c-s for biaxial calculation is OFF. If the ratio y/z is big, the program has to design many bars in one direction to  interaction formula was fullfilled, but result of interaction formula is small. This solution is often uneconomical design of reinforcement, therefore user can set limit ratio y/z via property Limit stress ratio (ratio y/z )_lim). If   ratio y/z > (ratio y/z )_lim or ratio y/z < 1/(ratio y/z )_lim ,then program gives warning 245 (An unusual design situation encountered: the stress ratio y/z exceeds the preset limit of the required reinforcement is hardly acceptable.Please, check the concrete setup) and user should:

• use different type of calculation (see chapter "4.1 Concrete setup for 1D member") in global or in local setting
• switch on the check box Optimize the number of bars in c-s for biaxial calculation, see chapter "4.1 Concrete setup for 1D member"
• use different type of caluclation for  ratio y/z, see chapter "4.1 Concrete setup for 1D member" in global or in local setting
• use different type of reinforcement area, see chapter "4.1 Concrete setup for 1D member"

The possibilty of correction calculation, when warning 245 is appeared, is presented in the table-.

4.1.3.1.6 Beams

There are the following items in group General > Calculation > Beams.

4.1.3.1.6.1 Calculate compression reinforcement

if this checkbox is set to YES, then compression reinforcement is automatically designed. This can happen when

Equilibrium was not found (583)

Depth of compression zone is bigger then allowed value – the tensile reinforcement is not fully exploited

4.1.3.1.6.2 Normal force to calculation

If this checkbox is set to YES the normal force from statical analysis is also taken into account for design of reinforcement

4.1.3.1.6.3 Check compression element (chapter 10.3.5 from "10 Literature")

If this checkbox is set to YES then member is checked if should be designed as column or not

IF  THEN member is considered as beam

IF   THEN member should be considered as column (E915) The user should change type of beam to column

4.1.3.1.6.4 Moment capping at the face of support/column

The comparison of the bending moments with and without capping for standard support and for column support is done in the following table

4.1.3.1.6.5 Shear force capping at supports

If this checkbox is set ON then shear force is reduced according to type of reduction in recalculated forces (for more information see part related to “Reduce shear force”)

4.1.3.1.6.6 Reduce shear force

Type of calculation of reduced shear force

A) At the face (support/column) - shear force above the support is the same as shear force in the face of the support/column

B) At the effective depth from the face (support/column) – shear force is calculated at distance d (effective depth of cross-section) from the face of support/column

4.1.4 Design strength

In this tab-sheet are parameters, which have influence directly to calculation design strength of the structure

4.1.4.1 Coefficient for maximum allowable value Pn

Design axial strength φ·Pn of compression members shall not be taken greater than φ·Pn,max, computed according to ACI 318-05,clause 10.3.6.1.The percentage of maximum allowable stresses from nominal axial strength can be set by this parameter, it means that following formula is used for calculation

The area of reinforcement is not subtracted from area of concrete in design reinforcement, because area of reinforcement is unknown, where this check is done

4.1.4.2 Equation for calculation EI for calculation Pc

In calculation magnified moments for sway or non-sway frame (see chapter "7.2 Internal forces for 1D members (beam, beam as slab, column)"), it is necessary to calculate critical column load (value P_c). This critical column load (Euler buckling load) depends on flexural stiffness of compression member (value EI), which in code ACI 318-05 can be calculated by two ways.

• According to equation 10-11

• According to equation 10-12

The calculated values of flexural stiffness’s are presented in the service Internal forces (tree Concrete > 1D member), if values My,recalc or My,recalc are selected, see chapter "7.2 Internal forces for 1D members (beam, beam as slab, column)"

4.1.4.3 Maximum strain for non-prestressed flexural member

For nonprestressed flexural members and nonprestressed members with factored axial compressive load less than 0.10fc′Ag the strain in most tensioned reinforcement (value ε_t) has to be greater than defined value in edit box, see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)" and "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)".

ε_t  ≥ε_t,max =0,004

If condition above is not fulfilled, then the calculation finished with error 916 (The cross-section is not ductile).

4.1.4.4 Group Ratio BetaD

Creep due to sustained load will increase the lateral deflections of a column and hence the moment magnification..This is approximated for design by reducing the stiffness EI (see chapter 4.1.4.2 Equation for calculation EI for calculation Pc) used for calculation critical column load (value P_c) by dividing EI by equation (1+β_d). There are two basic properties (two type of calculation factor +β_d ) in this group:

• Automatic calculation
• User input

Type of calculation

This setting allows to set type of calculation of factor β_d:

• Automatic calculation -  factor β_d is calculated as ratio of the factored axial sustained load (P_u,s) to the factored axial load (P_u) in the section of the compression member. It means:

• User input – the value of factor β_d is input directly in edit box, see chapter "4.1 Concrete setup for 1D member"

User input

This edit box is used for inputting user input of factor β_d . It is active only, if item User input is selected in group Ratio BetaD

4.1.4.5 Group Strength reduction factor Phi

Design strength of the structure is calculated multiplying the nominal strength by a strength reduction factor φ. The values of this factor for different situation are defined in ACI-318-05, clause 9.3.2. Here user can define default value of strength reduction factor for basic situation.

4.1.4.5.1 Compression controlled section

This factor should be used for calculation if tensile reinforcement in reinforcement (value ε_t) is lesser than 0.002.

For design reinforcement of beams (see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)") this factor is used in following case:

• if check box Use iterative calculation for design reinforcement is ON and concrete member data is not defined or is defined with Type of strength reduction factor = Calculated , then this value is used if ε_t ≥ 0.005 or this value is used for calculation new strength reduction factor for transition zone , if  0.005>ε_t >0.004
• if check box Use iterative calculation for design reinforcement is OFF and concrete member data is not defined or is defined with Type of strength reduction factor = Calculated , then this value is always used

For design reinforcement in column (see chapter "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)") this factor is used in following cases,

• if check box Use iterative calculation for design reinforcement is ON and concrete member data is not defined or is defined with Type of strength reduction factor = Calculated , then this value is used if ε_t ≥ 0.005 or this value is used for calculation new strength reduction factor for transition zone , if  0.005>ε_t >0.002
• if check box Use iterative calculation for design reinforcement is OFF and concrete member data is not defined or is defined with Type of strength reduction factor = Calculated , then this value is used if N_u ≥0

4.1.4.5.3 Shear and torsion

This factor is used for calculation design shear strength, see chapter  "8.2 Design of reinforcement for 1D members (beams, beams as slab, columns)".

4.1.4.6 Reduction factor for moment of inertia

According to clause 10.1.1 in ACI 318-05, it is possible to use alternative values of moment of inertia for the calculation. Reduction factor for moment of inertia of columns and beams can be set in this group and this reduction factors will be only used for calculation value  ψ_Ay(z) and ψ_By(z), which are used for calculation  effective length factor according code ACI (code dependent method for calculation effective length factor ), see chapter "5.4 Member buckling data".

Beams

This factor is used for reduction moment of inertia of beams in calculation coefficient ψ_Ay(z) and ψ_By(z), which are used for calculation effective length factor according to code dependent method

I_g,red,y(z) = red_b· I_g,y(z)

Columns

This factor is used for reduction moment of inertia of columns in calculation coefficient ψ_Ay(z) and ψ_By(z), which are used for calculation effective length factor according to code dependent method

I_g,red,,y(z) = red_c· I_g,y(z)

4.1.4.7 Design strength > Shear

There is only one value in part Design strength > Shear.

4.1.4.7.1 Maximal value fy and fyt for shear (chapter 11.5.2 from ACI 318-05)

This value is maximal available yield strength of the reinforcement used for the design of shear reinforcement. If user inputs bigger value then maximal value from concrete setup is taken into account

4.1.5 Detailing provisions

Generally detailing provisions are split to detailing provisions for beams and columns. Each type of memebr (beam or column) has the different detailing provisions for design of longitudinal and shear reinforcement.

4.1.5.1 Beams

4.1.5.1.1 Longitudinal reinforcement

There are the following items in the part Detailing provisions > Beams > Longitudinal reinforcement.

4.1.5.1.1.1 Min reinf. factor, x*fc’^0,5/fy (chapter 10.5.1 from ACI 318-05)

This value is minimal reinforcement factor during design of longitudinal reinforcement in beams. Value x is user defined value and default is 3,0 for US unit format and 0,25 for metric format

4.1.5.1.1.2 Min reinf. factor, x/fy (chapter 10.5.1 from ACI 318-05)

This value is minimal reinforcement factor during design of longitudinal reinforcement in beams. Value x is user defined value and default is 200 for US unit format and 1,4 for metric format

4.1.5.1.1.3 Max. reinf. (tensile strain eps_t for max.reinf – chapter 10.3.5 from ACI 318-05)

This value is minimal strain in reinforcement which is allowed for beams where axial load is ; otherwise the cross-section is not ductile

4.1.5.1.1.4 Min. clear bars spacing (chapter 7.6.1 from ACI 318-05)

This value prescribes minimum clear distance between bars; default value is diameter of the bar

4.1.5.1.1.5 Min. clear bars spacing (chapter 7.6.1 from ACI 318-05)

This value prescribes minimum clear distance between bars; default value is 1 inch

4.1.5.1.1.6 Max. centre-to-centre bars spacing

This is the user defined value of maximal clear spacing between longitudinal bars. It is code independent value

4.1.5.1.1.7 Check max. centre-to-centre bars spacing (chapter 10.6.4 fromACI 318-05)

This item prescribes maximal allowed centre to centre bars spacing between longitudinal bars based on the chapter 10.6.4 from ACI 318-05.

4.1.5.1.2 Shear reinforcement

There are the following items in the part Detailing provisions > Beams > Shear reinforcement.

4.1.5.1.2.1 Check max. centre-to-centre spacing (chapter 11.5.5 fromACI 318-05)

This item prescribes maximal allowed centre to centre spacing between stirrups legs based on the chapter 11.5.5 from ACI 318-05.

There are two values in combobox

Unit format	Formula	spacing
US
Metric

Where value

4.1.5.1.2.2 Check min. Area Av.min = x*bw*s/fyt (chapter 11.5.6 fromACI 318-05)

This item prescribes minimal area of shear reinforcement based on the chapter 11.5.6 from ACI 318-05.

There are two values in combobox

Unit format	Formula	spacing
US
Metric

4.1.5.1.2.3 Check diameter (chapter 7.10.5.1 fromACI 318-05)

This item prescribes minimal diameter of shear reinforcement based on the chapter 7.10.5.1 from ACI 318-05.

There are two values in combobox

Unit format	Formula	spacing
US
Metric

4.1.5.1.2.4 Maximal transverse spacing of the legs

This item prescribes maximal allowable transverse spacing of the stirrups legs. It is code independent value

4.1.5.2 Columns

4.1.5.2.1 Group longitudinal reinforcement

There are defined detailing provisions for design of longitudinal reinforcement to column

4.1.5.2.1.1 Min. reinf. percentage

If this check box is ON, then minimum area of longitudinal reinforcement is checked according to clause 10.9.1 in ACI 318-05. If area of longitudinal reinforcement is lesser than minimum area of reinforcement, then

                                           A_s = A_s,min = x·A_g /100

and design of longitudinal reinforcement finishes with warning 2 (The main reinforcement area was designed according to min. Required reinforcement percentage)

4.1.5.2.1.2 Max. reinf. percentage

If this check box is ON, then maximum area of longitudinal reinforcement is checked according to clause 10.9.1 in ACI 318-05. If area of longitudinal reinforcement is greater than maximum area of reinforcement ( A_s> A_s,max = x·A_g /100 ) then design of longitudinal reinforcement finishes with warning 502 (The percentage of designed reinforcement is higher than the maximum percentage)

4.1.5.2.1.3 Min. clear bars spacing

If this check box is ON, then minimum clear spacing between bars  is checked according to clause 7.6.1 in ACI 318-05. If clear spacing of bars is lesser than minimum spacing then design of longitudinal reinforcement finishes with the following warnings

4.1.5.2.1.4 Min. clear bars spacing

If this check box is ON, then minimum clear spacing between bars is checked according to clause 7.6.1 in ACI 318-05. If clear spacing of bars is lesser than minimum spacing then design of longitudinal reinforcement finishes with If clear spacing of bars is lesser than minimum spacing then design of longitudinal reinforcement finishes with the following warnings.

4.1.5.2.1.5 Max. bars spacing

If this check box is ON, then centre-centre spacing between bars is checked. This is code independently check. If this centre-centre spacing of bars is bigger than maximum spacing then design of longitudinal reinforcement finishes with the following warnings

4.1.5.2.1.6 Min. number of bars

If this check box is ON, then in design of reinforcement minimum number of bars according to clause 10.9.2 in ACI 318-05 is used for calculation, though number of bars from design reinforcement is lesser. For rectangular column minimum numbers of bars is always 4, independently on value defined in this property. This setting is used for number of bars in circular column.

4.1.5.2.2 Group transverse reinforcement

There are defined detailing provisions for design of transverse reinforcement (ties) to column

4.1.5.2.2.1 Max.spacing – number of long diameter

If this check box is ON, then spacing of bars as multiple of diameter of longitudinal reinforcement bars   according to clause 7.10.5.2 in ACI 318-05 is taken into account for design transverse reinforcement (maximum vertical spacing of ties)

s_s,min,1 = x·d_b

4.1.5.2.2.2 Max.spacing – least dimension of column

If this check box is ON, then spacing of bars as least dimension of column   according to clause 7.10.5.2 in ACI 318-05 is taken into account for design transverse reinforcement (maximum vertical spacing of ties)

s_s,min,2 = min (b;h)

4.1.5.2.2.3 Max.spacing – number of tie diameter

If this check box is ON, then spacing of bars as multiple of tie diameter   according to clause 7.10.5.2 in ACI 318-05 is taken into account for design transverse reinforcement (maximum vertical spacing of ties)

s_s,min,3 = x·d_s

4.1.5.2.2.4 Check diameter

If this check box is ON, then minimum diameter of shear reinforcement (ties)   according to clause 7.10.5.1 in ACI 318-05 is checked during design of shear reinforcement. Minimum diameter of shear reinforcement depends on diameter of longitudinal reinforcement, which enclosed, see table below.

If diameter of shear reinforcement   is lesser than minimum diameter of shear reinforcement, then design of shear reinforcement finishes with warning 163 (The profile diameter of shear reinforcement is lesser than permitted). In this case, value shear reinforcement has to be increased in concrete setup or concrete member data.

If diameter of shear reinforcement   is lesser than minimum diameter of shear reinforcement, then design of shear reinforcement finishes with warning 163 (The profile diameter of shear reinforcement is lesser than permitted). In this case, value shear reinforcement has to be increased in concrete setup or concrete member data.

4.1.5.2.2.5 Max transverse spacing of the legs

The value from edit box (value s_t,max) is used for calculation number of cuts of shear reinforcement independently if check box is ON or OFF. This value is used for:

• Calculation of number of cuts  , if concrete member data is not defined on the member
• Automatic calculation number of cut in concrete member data, if it is defined on the member

Number of cuts is calculated according to formula

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