Define Pushover Hinge Properties

Define the plastic hinge data to be used in Pushover analysis.

Note

Hinge properties such as yield strength are calculated based on the specified design code in Design>Concrete/Steel Design Parameter>Design code.

From the Main Menu select Design > Pushover Analysis > Define Hinge Properties

Define Pushover Hinge Data dialog box

Click the button to define plastic hinge information in the dialog box below. Click the button to confirm or modify and the button to delete the data entry. Select the pushover hinge to be copied in the dialog box and click button.

After defining the hinge type and assigning it to the selected members, check on the Show Generated Hinges in the Define Pushover Hinge Data dialog box to check the automatically calculated hinge data by the section information. Select the hinge data to be checked and click the button to prompt the Add/Modify Hinge Data Type dialog box in which the button is clicked to check the hinge data. Corrections to the assigned hinge data are not permitted here.

Note 1

When members are assigned hinge properties, inherent titles are assigned to the automatically generated hinge data. For example, "B1-PMM" represents:

B: Hinge assigned to a beam element

1: Sequential number assigned to by element types

Beam: Assigned hinge type (Beam, Column, PMM…)

Note 2

Hinge properties of each element are automatically generated according to the sectional information. For reinforced concrete members, reinforcing steel must be pre-determined through the design feature in Gen. Reinforcing steel data for the relevant sections must be provided in Modify Beam (Column, Brace & Wall) Section Data of Concrete Design Parameter. If the automatic design feature for reinforced concrete members (Concrete Code Design) is used, you are required to enter the reinforcing data using the button in the Design Result dialog box for each element.

Note 3

Strength calculation method for Value Type Steel Section

1. Sectional information such as Area, Asy, Asz, Cym, Cyp, Czm, Czp, Zyy, and Zzz cannot be 0 for auto-calculation

    (Zyy, Zzz are new items added in Value Type and can be checked in Model > property > Section).

2. Hinge strength is calculated for P, My-Mz, Vy-Vz, and PMM.

3. For Yielding, the PM-Curve is generated on the basis of Pc (compressive strength), Pt (tensile strength), and M0 (flexural

 strength at P=0, or Fy×yy, Fy×zz).

4. For Ultimate, the PM-Curve is generated on the basis of Pc (compressive strength), Pt (tensile strength), and M0 (flexural

  strength at P=0, or Fy×Zyy, Fy×zz).

                      Add/Modify Hinge Data Type dialog box

Hinge Properties Type Name

Define names of plastic hinge properties.

Description

State a brief description related to the pushover hinge properties.

Element  Type

Specify the type of element.

Beam/Column : Beam or Column element       

Wall : Wall element

Truss : Truss element                                          

General Link : Spring which can be defined at Model>Boundaries>Define General Link Properties

Wall  Type

Specify the type of wall element.

Membrane : Only in-plane plasticity is considered    

Plate : Both in-plane and out-of-plane plasticity are considered  

Material Type

Specify the type of material used to the corresponding element.

RC / SRC (encased) : RC or SRC (Steel-encased concrete type)

Steel / SRC (filled) : Steel or SRC (Concrete-filled steel tube type)  

Masonry : Masonry type

Definition

Specify the load-deformation relationship of the flexural member.

Moment-Rotation (M-θ)

Moment-Curvature (M-φ Lumped)

Moment-Curvature (M-φ Distributed)

Pier Type : For vertical members in the masonry material type. Hinge properties are defined in terms of moment-rotation

relationship for a member’s section.

Spandrel Type : For horizontal members in the masonry material type. Hinge properties are defined in terms of moment-

rotation relationship for a member’s section.  

Interaction Type

None : Axial force and biaxial moments are uncoupled from each other.

P-M-M in Status Determination : Coupled axial force-biaxial moment behavior is reflected by calculating the flexural yield strength of a hinge considering the effect of axial force.

Component Properties

Fx, Fy, Fz, Mx, My, Mz : Check on the degree of freedom to be assigned to the plastic hinge type.

Hinge Location : Specify the hinge location within the corresponding element.

Number of Section : Specify the number of integration points when Definition is selected as 'Moment-Curvature (M-φ Distributed)'.

Skeleton Curve : Specify the skeleton curve.

Note 1

The skeleton curves available are as follows:

1. Bilinear Type (or Slip Bilinear Type)

2. Trilinear Type (or Slip Trilinear Type).  

3. FEMA Type

4. Eurocode8:2004

Slip Bilinear Type or Slip Trilinear Type is activated when the Element Type is defined as 'Truss' or 'General Link'.

Note 2

The Multi-Linear Type is applicable for both the load control and the displacement control methods and both FEMA and Eurocode 8 type is applicable only for the displacement control method.

Enter the relevant hinge properties in the following dialog box:

• When Interaction Type is None and Skeleton Curve is Bilinear / Trilinear type

   

  

  Hinge Property Data dialog box (Multi-Linear Type)

   

  Input Method

   

  Auto-Calculation : The corresponding yield strength is automatically calculated based on the design code.

  Note

  Following definitions are required for Auto-Calculation.

  1. Design Code

  2. Material and section properties defined from the standards

  3. Rebar data for RC members  

   

  User Input : All the input data are user-defined parameters.

   

  Input Type

   

  Strength - Stiffness Reduction Ratio : Define the Skeleton Curve using the yield strength and the stiffness reduction ratio.

   

  Strength - Yield Deformation : Define the Skeleton Curve using the yield strength and the yield deformation defined by the user.

   

  Note

  1. Strength - Yield Deformation option is activated when the Input Method is set to User Input.

  2. Yield Deformation is changed depending on the component. (Fx : yield deformation, Fy & Fz : yield strain, Mx & My & Mz : yield rotation angle)

   

  Value Type of I-End & J-End

   

  Symmetric : Select if rebar arrangement between i-end and j-end are symmetrical.

   

  Asymmetric : Select if rebar arrangement between i-end and j-end are asymmetrical.

   

  Note

  Value Type of I-End & J-End option is activated when the hinge type is defined as Moment-Rotation (M-Θ) or Moment-Curvature (M-φ Lumped) and User Input option is selected. The asymmetrical yield strengths between I-end and J-end are automatically reflected when input method is set to Auto-Calculation. 

   

  Type

   

  Symmetric : Select if the hinge properties are symmetric in the positive and negative directions.

   

  Asymmetric : Select if the hinge properties are asymmetric in the positive and negative directions.

   

  Yield Strength

   

  The values are automatically calculated using the section information if Input Method is set to Auto-Calculation. Or the user may enter the values of Yield Moment and Yield Rotation manually if Input Method is User-Input.

   

  P1: 1st Yield Strength      

    It represents the cracking strength of concrete or the member force of a structural steel member at the time the top or bottom fiber starts yielding. 

   

  P2: 2nd Yield Strength

   It represents the starting point of concrete rupture or yielding of reinforcing steel. In the case of structural steel, it represents the

   member force at which an entire member starts yielding.

   

  Note

  The values for the 2nd My must be greater than those for the 1st My (Mcr). 

   

  Stiffness Reduction Ratio

   

  Use Value of Global Control Data : Stiffness reduction ratio defined in Pushover Global Control dialog is used.
   

  User Defined : User defined stiffness reduction ratio is used.

   

  Initial Stiffness

   

  6EI/L, 3EI/L, 2EI/L : It is activated when Definition is defined as Moment - Rotation (M-θ).  

   

  User : Defined by the user

   

  Elastic Stiffness：Elastic stiffness is used for the initial stiffness.

   

  Initial Gap

   

  Enter the initial gap in tension and compression when element type is Truss or General Link for the Slip Bilinear Type or Slip Trilinear Type of skeleton curve.  

   

•  When Interaction Type is None and Skeleton Curve is FEMA

   

  

   

  Hinge Property Data dialog box (FEMA Type)

   

  Input Method

   

  Auto-Calculation : The corresponding yield strength is automatically calculated based on the design code.

   

  Note

  Following definitions are required for Auto-Calculation.

  1. Design Code

  2. Material and section properties defined from the standards

  3. Rebar data for RC members  

   

  User Input : All the input data are user-defined parameters.

   

  Value Type of I-End & J-End

   

  Symmetric : Select if rebar arrangement between i-end and j-end are symmetrical.

   

  Asymmetric : Select if rebar arrangement between i-end and j-end are asymmetrical. 

   

  Note

  Value Type of I-End & J-End option is activated when the hinge type is defined as Moment-Rotation (M-Θ) or Moment-Curvature (M-φ Lumped) and User Input option is selected. The asymmetrical yield strengths between I-end and J-end are automatically reflected when input method is set to Auto-Calculation. 

   

  Type

   

  Symmetric : Select if the hinge properties are symmetric in the positive and negative directions.

   

  Asymmetric : Select if the hinge properties are asymmetric in the positive and negative directions.

   

  Yield Strength (MY)

   

  The values are automatically calculated using the section information if Input Method is set to Auto-Calculation. Or the user may enter the values of Yield Moment manually if Input Method is set to User-Input. The coordinate system follows the Element local Coordinate System.  

   

  Yield Rotation (DY)

   

  User Defined

  The values are automatically calculated using the section information if this option is checked off. Or the user may enter the values of Yield Rotation manually. The coordinate system follows the Element local Coordinate System. 

   

  Acceptance Criteria (Current Deform./Yield Deform.)

   

  Enter the target performance indices for the structure in terms of ductility (Total Deformation/Yield Deformation). The values outlined in FEMA-273 are used as the reference values. Only positive values are entered if the case is symmetrical.  

   

  Note

  The legend identifying the status of hinge formation reflects the Acceptance Criteria after pushover analysis is completed. Select Hinge Status in Type of Display in Deformed Shape to observe the status of hinge formation by incremental steps.

   

  

   

   

  Initial Stiffness

   

  6EI/L, 3EI/L, 2EI/L : It is activated when Definition is defined as Moment - Rotation (M-θ). 

   

  User : Defined by the user

   

  Elastic Stiffness：Elastic stiffness is used for the initial stiffness.

   

  

  The Yield Surface Properties button enables us to define the interaction of axial force and bending moments where P-M-M in Status Determination of interaction type is selected.

•  When Interaction Type is None and Skeleton Curve is Eurocode 8: 2004

  

   

  Hinge Property Data dialog box (Eurocode 8: 2004 Type)

   

  Input Method

   

  Auto-Calculation : The corresponding yield strength is automatically calculated based on the design code.

   

  Note

  Following definitions are required for Auto-Calculation.

  1. Design Code

  2. Material and section properties defined from the standards

  3. Rebar data for RC members  

   

  User Input : All the input data are user-defined parameters.

   

   

  Value Type of I-End & J-End

   

  Symmetric : Select if rebar arrangement between i-end and j-end are symmetrical.

   

  Asymmetric : Select if rebar arrangement between i-end and j-end are asymmetrical. 

   

  Note

  Value Type of I-End & J-End option is activated when the hinge type is defined as Moment-Rotation (M-Θ) or Moment-Curvature (M-φ Lumped) and User Input option is selected. The asymmetrical yield strengths between I-end and J-end are automatically reflected when input method is set to Auto-Calculation. 

   

  Type

   

  Symmetric : Select if the hinge properties are symmetric in the positive and negative directions.

   

  Asymmetric : Select if the hinge properties are asymmetric in the positive and negative directions.

   

  Yield Strength (MY)

   

  The values are automatically calculated using the section information if Input Method is set to Auto-Calculation. Or the user may enter the values of Yield Moment manually if Input Method is set to User-Input. The coordinate system follows the Element local Coordinate System.  

   

  Yield Rotation (DY)

   

  User Defined

  The values are automatically calculated using the section information if this option is checked off. Or the user may enter the values of Yield Rotation manually. The coordinate system follows the Element local Coordinate System. 

   

  Class of Cross Section

   

  Rotation capacity at the end of steel beams or columns depends on the class of cross section. In order for the program to automatically determine the class of cross section for the pushover analysis, select ‘Auto’. For the automatic classification Steel Code Checking should be performed first.

   

  

   

  Compliance Criteria

   

  Enter the target performance indices for the structure in terms of deformation. The values outlined in Eurocode 8-3 are used as the basic values. Only positive values are entered if symmetrical.   

   

  Note

  The legend identifying the status of hinge formation reflects the Compliance Criteria after pushover analysis is completed.

   

  

   

  Initial Stiffness

   

  By default, initial stiffness of moment hinge is taken equal to the Yield Strength divided by Yield Rotation, and the Yield Strength and Yield Rotation are automatically calculated based on Eurocode 8 part 1 & 3. Any safety factors including partial factors are not reflected in the calculation of strength and deformation.

   

  6EI/L, 3EI/L, 2EI/L : It is activated when Definition is defined as Moment - Rotation (M-θ). 

   

  User : The initial stiffness that has been automatically calculated is displayed here. If the value is

  modified, the modified value will be applied as the initial stiffness.

   

  Elastic Stiffness：Elastic stiffness is used for the initial stiffness.

   

  

  The Yield Surface Properties button enables us to define the interaction of axial force and bending moments where P-M-M in Status Determination of interaction type is selected.

•  When Interaction Type is P-M-M in Status Determination

   

  

   

  Define/Show Interaction Surface dialog box

   

  Input Method

   

  User : All the input data are user-defined parameters.

   

  Auto : The corresponding yield strength is automatically calculated based on the design code.

   

   

  Value Type of I-End & J-End

   

  Symmetric : Select if rebar arrangement between i-end and j-end are symmetrical.

   

  Asymmetric : Select if rebar arrangement between i-end and j-end are asymmetrical.

   

  Note

  Value Type of I-End & J-End option is activated when the hinge type is defined as Moment-Rotation (M-Θ) or Moment-Curvature (M-φ Lumped) and User Input option is selected. The asymmetrical yield strengths between I-end and J-end are automatically reflected when input method is set to Auto-Calculation. 

   

   

  Type (Y-Axis, Z-Axis)

   

  Symmetric : Select if the hinge properties in Y-axis and Z-axis are symmetrical.

   

  Asymmetric : Select if the hinge properties in Y-axis and Z-axis are asymmetrical.

   

   

  Component Properties

   

  Define the skeleton curve and initial stiffness, etc for the rotation about y-axis and z-axis.

   

   

  Type (Plus, Minus)

   

  Symmetric : Select if the hinge properties in the positive and negative moment are symmetrical.

   

  Asymmetric : Select if the hinge properties in the positive and negative moment are asymmetrical.

   

   

  Yield Strengths

   

  Yield strength about y-axis and z-axis are automatically calculated using the section information if Input Method is set to Auto. Or the user may enter the values of Yield Moment manually if Input Method is set to User.

   

   

  Interpolation Method : My-Mz

   

  PM interaction curve is interpolated by the Bresler's Load Contour Method. The curve may be of elliptic, linear or user-defined shape. The values of Alpha, 1 and 2 represent linear and elliptic shapes respectively.

   

   

  Note

  If the User defines the interpolation method, the bi-axial moment is formulated by the Bresler's Load Contour Method. In a 3-dimentional interaction diagram, the curve on a Mx-My plane passing a given Pn is represented by the expression

   

  

   

  If   is assumed, the expression becomes,

   

  

   

  In general, retains a value in the range of 1.0-2.0 in a rectangular section. If is set at 1.0, the curve becomes a straight line and as such it produces the most conservative design. The value of 1.5 may result in a close approximation.

   

   

  Shape of the 1st and 2nd P-M Interaction Curves

   

  Yield surface about strong and weak axes can be checked by table or graph.  

   

  Show Value : Click to display the applied forces and moments in analysis.

   

   

   

  NoteDefinition of yield strength and yield surface by Skeleton Curve types

   

   

  1. RC Trilinear

   

  

   

  2. RC Bilinear, FEMA, EC8

   

  

   

  3. Steel Trilinear

   

  

   

  4. Steel Bilinear, FEMA, EC8

   

  

   

   

   

   

   

Note Hinge properties by Element Types and Definitions

Masonry Properties

In the structural model, masonry spandrels may be taken into account as coupling beams between two wall elements. This assumption implies that they should regularly bonded to the adjoining walls and connected both to the floor tie beam and to the lintel below. If the structural model takes into account the coupling beams, a frame analysis may be used for the determination of the action effects on the vertical and horizontal structural elements.

•   When Pier Type is selected.

  

   

  Masonry Properties dialog box (Pier type)

   

  Building Type: Flexural capacity and shear resistance of masonry pier depends on the type of building as shown in the table below.

   

  

   

  Following data are required to calculate the resistance of masonry pier.

   

  Compressive Strength (fm)

   

  Shear Strength (t0)

   

  Vertical Stress Distribution Coefficient (k)

   

   

  Note 1 How to calculate the resistance

   

  - Axial resistance:

   

  

  - Shear resistance:

   

  

   

  - Flexural resistance

   

  

   

  Note 2

  Calculated resistance can be checked in Design > Pushover Analysis > Pushover Hinge Result Table >Beam Summary table.

   

   

  Note 3Element Local axis of masonry wall pier

   

  In-plane horizontal direction and transverse direction of the wall pier should coincide with the local z-axis and local y-axis of the element, respectively as shown in the figure below, which directly affects the resistance of the wall pier. Also, the program calculates hinge properties (My component) on the assumption above.  

   

  

   

•  When Spandrel Type is selected.

  

   

  Masonry Properties dialog box (Spandrel type)

   

  Following data are required to calculate the resistance of masonry spandrel.

   

  Horizontal Compressive Strength (fhd)

   

  Shear Strength in absence of Vertical Loads (fvk0)

   

  Hp

   

  Note 1 How to calculate the resistance

   

  - Axial resistance:

   

  

   

  - Shear resistance:

   

  

   

  - Flexural resistance:

   

  

   

  Note 2

  Calculated resistance can be checked in Design > Pushover Analysis > Pushover Hinge Result Table > Beam Summary table.