Rebar Material Properties

 

 

Define material properties for rebars.

 

 

 

From the Main Menu select Model > Rebar > Rebar Material Property.

Double Click under the Section name in the Works Tree.

Click Rebar Material Property in the Icon Menu.

 

 

 

Rebar Material Properties  dialog box

Rebar Material Code

Select the rebar material code of a country.

ASTM(RC): American Society for Testing Materials

CSA(RC): Canadian Standards Association

BS(RC): British Standard

Note
When material data are defined per BS or Chinese Standards, Cubic compressive strength is used as opposed to Cylinder strength.   

EN04(RC): European Code

JIS(RC): Japanese Industrial Standards

GB(RC): Chinese National Standard

GB-Civil(RC): Chinese National Standard

JTG04(RC): Chinese Technical Standard of Highway Engineering

TB05(RC): TB 10002.3-2005 (Code for design on reinforced and prestressed concrete structure of railway bridge and culvert)

KS01(RC): Korea Industrial Standards (in SI unit system)

KS(RC): Korean Industrial Standards (in MKS unit system)

KS-Civil(RC): Korean Civil Standards

IS(RC): Indian Standards

CNS(RC): Chinese National Standard

  UNI(RC): Italian National Standards

Rebar Grade

Select the grade of the rebar material from the drop down list.

Rebar Fy

Yield strength of rebar

Modulus of Elasticity

Modulus of Elasticity

Stress Strain Curve

Assign stress-strain curve to the rebar material.

Elastic-only

Bilinear Model : Click to define the parameters.

This model represents a general symmetric Bilinear model for reinforcing steel.

 

fy: Yield strength of reinforcing steel

E1: Initial stiffness of reinforcing steel

E2/E1: Ratio of stiffness after yielding to the initial stiffness

As shown in the figure below, the model behaves elastically when it is unloaded and reloaded after yielding.

 

 

 

Menegotto-Pinto: Click to define the parameters

This is the steel model of Menegotto and Pinto, which was modified by Filippou et al.

 

fy: Yield strength of reinforcing steel

E: Modulus of elasticity

b: Stiffness reduction factor after yielding

Ro, a1, a2: Coefficients for shape index (R) for steel fiber constitutive model

This Stress-Strain hysteresis model is outlined as follows:

The above formula represents a curved transition from the elastic range to the yielding range.

 and  are normalized values and are calculated as follows:

 

The above formula represents a curved transition from the elastic range to the yielding range.

and   are normalized values and are calculated as follows:

 

 This model has two asymptotes as shown below. One asymptote has a slope of elastic stiffness and the other has a slope of yielding stiffness.   is a point intersected by two asymptotes.   is the point where the last unloading occurred. While unloading and reloading, these points are updated, so that the transition curve is affected.

R is the value that can affect the shape of the transition curve and represents the Bauschinger effect. The value of R is determined as follows:

Coefficients    are determined from experimental hysteresis results. MIDAS uses 18.5, 0.15 and 20, respectively, as default values. These default values are suggested in the original reference (Menegotto and Pinto,1973).

 is a shape coefficient and updated at every unloading.

 

 

Park-Strain Hardening: Click to define the parameters

This is the steel model of Park's Strain Hardening.

 

fy: Yield strength of reinforcing steel

e1y: Yield tensile strain of reinforcing steel

fu: Ultimate strength of reinforcing steel

eu: Ultimate tensile strain of reinforcing steel

 

The above formula represents a curved transition after the yield strength.

 and  are normalized values and are calculated as follows: