Design Code

Determine the design code and the special provisions for seismic design (if required) to perform the design or the strength verification for RC members according to the following Concrete Design Criteria:

• EN 1992-1-1:1994 Eurocode2, Design of concrete structures Part 1 (Eurocode2:04)

• ENV 1992-1-1:1992 Eurocode2, Design of concrete structures Part 1 (Eurocode2)

• Ultimate Strength Design, the American Concrete Institute (ACI318-14/11/08/05/02/99/95/89)

• Colombian Earthquake Resistance Building Code Ultimate Strength Design (NSR-10)

• Canadian Standards Association of Concrete Structures (CSA-A23.3-94)

• British Standard, Structural use of concrete Part 1 (BS8110-97)

• Taiwanese Standard (TWN-USD100/92)

• Indian Standard (IS456:2000)

• Architectural Institute of Japan (AIJ-WSD99)

• China Standard (GB50010-10/02)

• Architectural Institute of Korea (AIK-USD94)

• Korean Society of Civil Engineers (KSCE-USD96)

• Korean Concrete Institute (KCI-USD12/07/03/99)

• Architectural Institute of Korea (AIK-WSD2K)

Note 1

 If the user omits the design code, the Concrete Structure Design Code of the European Standard (Eurocode2:04) is applied by default.

Note 2

Following section types and shapes are applicable in Steel Code Checking.

Applicable section type: DB/User type

Applicable section shape for Beam: Solid Rectangle, T-Section

Applicable section shape for Column: Solid Rectangle, Solid Round, Pipe

From the Main Menu select Design > Design > RC Design > Design Code

[When Eurocode2:04 is selected]

Design Code

RC design code.

National Annex

National Annex for Eurocode2:04.

Note. Available National Annexes are as follows:

Recommended

Italy

Sweden

Singapore

Apply NTC

 NTC2008

 Option to apply the capacity design rule as per NTC2008

 NTC2012

 Option to apply the capacity design rule as per NTC2012

 NTC2018

 Option to apply the capacity design rule as per NTC2018

Note. How to calculate design forces of capacity design as per NTC

Apply Special Provisions for Seismic Design

Option to apply the capacity design rule as per EN1998-1:2004

Note. How to calculate design forces of capacity design as per EN1998-1:2004

Strut Angle for Shear Resistance

The angle between the concrete compression strut and the beam axis perpendicular to the shear force

Effective Creep Ratio ()

           is used in the following formula.

          Calculation of "A" in slenderness limit( ) as per EN1992-1-1:2004    

          Calculation of Factor for accounting creep in additional second order moment as per EN1992-1-1:2004 and NTC2018

        Where,

          M2 : Additional second order moment (=Ned x e2)

          e2 : Deflection

          l0 : Effective Length

          c: depends on curvature distribution, program uses c=10 as recommended by code.

          The value of c cannot be changed by user.

            Kr : (nu-n)/(nu-nbal) Correction factor for axial load

                   n=Ned/Ac fcd relative axial force

                 =0.105 (Recommended) Different value cannot be specified.

                   nbal =0.4 (Recommended) Different value cannot be specified.

          Default Value of =2.14

          In Eurocode, Default value of "A" is 0.7, and to satisfy "A=0.7" is "2.14".(see"Slenderness Limit")

Slenderness Limit

 (5.13N) in EN1992-1-1:2004

(Default value is '0.7'.)

 (Default value is '1.1'.)

(Default setting is 'Calculate by Program'.)

  (5.13N) in NTC2018

 n = Ned / (Ac x fcd)

 Ned : Axial force

 Ac : Area  of cross section

Strong Column Weak Beam

Define the ratio to satisfy the ductility condition at all the joints. Default value is '1.3'.

 eq. (4.9) in EN1998-1:2004

Select Ductility Class

For EC8:04

DCH: High ductility level

DCM: Medium ductility level

For NTC2018

CD "A": High ductility level

CD "B": Medium ductility level

Non-Dissipative : Low ductility level

Design Method of Non-Dissipative Member

Define  method of non-dissipative member design as per NTC2018.

M-C Curve  : Elastic moment resistance (M'yd) is obtained from Moment-Curvature Curve.

Approximate Method :  Elastic moment resistance (M'yd) = Reduction factor * Ultimate moment resistance (M_Rd)

Shear Force for Design (Gamma_rd)

Define the factor accounting for possible overstrength due to steel strain hardening

Default value is as follows:

Non-Dissipative Element

        Define the Non-dissipative  elements in order to carry out the elastic design

        * What is Non-dissipative elements design as per NTC 2018

Secondary Seismic Element

Define the secondary seismic elements in order to preclude the capacity design rule

Structure Information

Structure Type: Define structure type to calculate behavior factor and determine the wall design method

Behavior Factor (q): Behavior factor to account for energy dissipation capacity shall be derived for each design direction as follows:

Calculate by Program: Behavior factor is automatically calculated and applied to the capacity design.

Alpha u / Alpha 1: The multiplication factor for buildings which are regular in plan.

User Input: Behavior factor is directly entered by the user.

Note. Behavior factor for horizontal seismic actions

Elastic Response Spectrum

Default By Function: Select response spectrum function defined in Response Spectrum Function. The spectrums of 'Eurocode8' and 'User Type' are available.  

Spectrum Parameters

Soil Factor (S)

Tb: The lower limit of the period of the constant spectral acceleration branch

Tc : The upper limit of the period of the constant spectral acceleration branch

Td: The value defining the beginning of the constant displacement response range of the spectrum

Ref. Reak Ground Acc. (AgR): The design ground acceleration on type A ground

Importance Factor (I)

Viscous Damping Ratio (xi)

Consider Ved of elastic strength Load combination for primary members

V_Ed_1= V_Ed by LC_U

V_Ed_2 = Min [M_Rd_top+M_Rd_bot)/L for ULS, V_Ed by LC_E]

Here,

        LC_U : Load combinations for checking Ultimate Limit state (ULS)

        LC_E : Load combinations for checking Elastic Limit State (ELS)

Design shear force (V_Ed) = Max [V_Ed_1, V_Ed2]

Friction Coefficient for Wall Sliding

Define the concrete-to-concrete friction coefficient under cyclic actions, which may be assumed equal to 0.6 for smooth interfaces and to 0.7 for rough ones. The default value is 0.7.

Torsion Design

Check to consider torsion in design.

Consider Shear Strength of Concrete for Checking

Ignore the shear strength of concrete in the calculation of shear resistance for the walls and columns. By checking off this option, the shear resistance of members will be determined by shear reinforcement regardless of the amount of shear strength of concrete. This option works with the Concrete Code Check function.

[When ACI318-08/11/14 is selected]

Design Code

RC design code (refer to Note 1)

Check Beam Deflection (only ACI318-14 / ACI318M-14)

                        Options for calculation and evaluation of short/long-term deflection of beam

Apply Special Provisions for Seismic Design

Option to apply the special provisions for seismic design

Select Frame Type

Select the type of frame for seismic zone.

Special Moment Frames: Moment frame in strong-motion seismic zone

Intermediate Moment Frames: Moment frame in intermediate-motion seismic zone

Ordinary Moment Frames: Moment frame in weak-motion seismic zone

Shear Wall Type

Option to apply special structural walls. Select the condition as per Boundary Element Method.

Note : Boundary Element Methods are provided as per clause 21.9.6.2 and clause 21.9.6.3 of ACI 318-08 .

Shear for Design

Apply Scale up Factor for Shear as per special provisions for seismic design.

: Apply Scale up Factor for Shear as per a relevant code.

R*Vc(a1*SUM(Mpr)/L>max(Ve1,Ve2)/2)     

R: ACI318-05 Clause 21.3.4.2 indicates that " Transverse reinforcement shall be proportioned to resist shear assuming Vc=o when ...". In midas, even though such conditions occur, the user can include a part of shear strength of concrete as well as shear reinforcement.

Method: Select a method to apply Scale up Factor for Shear.

Max(Ve1, Ve2): Use the larger of the shear forces to which Scale up Factors for Shear (a1, a2) will have been applied.

Min(Ve 1, Ve 2): Use the lesser of the shear forces to which Scale up Factors for Shear (a1, a2) will have been applied.

Ve 1: Select to apply Scale up Factor for Shear (a1).

Ve 2: Select to apply Scale up Factor for Shear (a2).

Member Types to be excluded in Seismic Design :

Select the member types for which Seismic Design is to be excluded .We can also select individual members from Seismic Design Type.

 : Enter the selection and close the dialog box.

 : Do not enter the selection and close the dialog box.

[When ACI318-05 is selected]

Design Code

RC design code (refer to Note 1)

Apply Special Provisions for Seismic Design

Option to apply the special provisions for seismic design

 : Enter the selection and close the dialog box.

 : Do not enter the selection and close the dialog box.

Select Frame Type

Apply different Scale up Factor for Shear for each seismic zone (This is applicable for ACI318-89, 95, 99, 02,05).

Special Moment Frames: Moment frame in strong-motion seismic zone

Intermediate Moment Frames: Moment frame in intermediate-motion seismic zone

Ordinary Moment Frames: Moment frame in weak-motion seismic zone

Shear for Design

Apply Scale up Factor for Shear as per special provisions for seismic design.

: Apply Scale up Factor for Shear as per a relevant code.

R*Vc(a1*SUM(Mpr)/L>max(Ve1,Ve2)/2)     

R: ACI318-05 Clause 21.3.4.2 indicates that " Transverse reinforcement shall be proportioned to resist shear assuming Vc=o when ...". In midas, even though such conditions occur, the user can include a part of shear strength of concrete as well as shear reinforcement.

Method: Select a method to apply Scale up Factor for Shear.

Max(Ve1, Ve2): Use the larger of the shear forces to which Scale up Factors for Shear (a1, a2) will have been applied.

Min(Ve 1, Ve 2): Use the lesser of the shear forces to which Scale up Factors for Shear (a1, a2) will have been applied.

Ve 1: Select to apply Scale up Factor for Shear (a1).

Ve 2: Select to apply Scale up Factor for Shear (a2).

[When TWN-USD100 is selected]

Apply Special Provision for Seismic Design

Option to apply the special provision for seismic design.

Shear for Design

Apply Scale up Factor for Shear as per special provisions for seismic design.

: Apply Scale up Factor for Shear as per a relevant code.

R*Vc(a1*SUM(Mpr)/L>max(Ve1,Ve2)/2)     

R: ACI318-05 Clause 21.3.4.2 indicates that " Transverse reinforcement shall be proportioned to resist shear assuming Vc=o when ...". In midas, even though such conditions occur, the user can include a part of shear strength of concrete as well as shear reinforcement.

Method: Select a method to apply Scale up Factor for Shear.

Max(Ve1, Ve2): Use the larger of the shear forces to which Scale up Factors for Shear (a1, a2) will have been applied.

Min(Ve 1, Ve 2): Use the lesser of the shear forces to which Scale up Factors for Shear (a1, a2) will have been applied.

Ve 1: Select to apply Scale up Factor for Shear (a1).

Ve 2: Select to apply Scale up Factor for Shear (a2).

SCWB Design/Checking Method

Option for design force calculation  special provision for seismic design.

Design Strength: Perform strong column-weak beam design and checking using the design strength of beams ( ).

[Ductile Design & Checking calculation]

[Strong Column Weak Beam Ratio Calculation]

Nominal Strength: Perform strong column-weak beam design and checking using the nominal strength of beams ( ).

[Ductile Design & Checking calculation]

[Strong Column Weak Beam Ratio Calculation]

Torsion Design

Apply torsional design. This option is applicable for ACI318-14/11/08 & TWN-USD100/92 & IS456:2000 only.