Time Dependent Material (Creep/Shrinkage)

Define the time dependent creep and shrinkage material data for concrete. The properties are applied to Construction stage analysis and Heat of hydration analysis.

From the Main Menu select Properties > Time Dependent Material > Creep/Shrinkage.

Click to define a new time dependent material property (creep/shrinkage). Click and to change and delete the data previously entered. Click to copy previously entered data.

Name

Enter the name of the material property, which is referred to by Time Dependent Material Link.

Code

Define the Code for which Creep/Shrinkage material properties can be defined.

1. 1. •  When CEB-FIP(1990) is selected

        Characteristic Compressive strength of concrete at the age of 28 days

        Relative Humidity of ambient environment (40-99)

        Notational size of member

        Note
        1. In case the Notational Size of Member (h) for each element is different due to a changing section, ‘h’ for each element needs to be entered in Change Element Dependent Material Property.
        
        2. . In case the Composite Section for Construction Stage is used, ‘h’ for each Part needs to be entered in Composite Section for Construction Stage.

        Type of Cement

        Age of concrete at the beginning of shrinkage: The number of days elapsed after pouring of concrete, when the shrinkage is assumed to start.

          : Produce the auto-calculated time dependent material property in a graph.

         

      •  When CEB-FIP(1978) is selected

        Characteristic Compressive strength of concrete at the age of 28 days

        Relative Humidity of ambient environment (40, 50, 70, 100)

        Notational size of member

        Note

        1. In case the Notational Size of Member (h) for each element is different due to a changing section, ‘h’ for each element needs to be entered in Change Element Dependent Material Property.

        2. In case the Composite Section for Construction Stage is used, ‘h’ for each Part needs to be entered in Composite Section for Construction Stage.

        Type of Cement

        Age of concrete at the beginning of shrinkage: The number of days elapsed after pouring of concrete, when the shrinkage is assumed to start.

          : Produce the auto-calculated time dependent material property in a graph.

         

      •  When ACI209(1982) Code is selected

        Compressive strength of concrete at the age of 28 days

        Relative Humidity of ambient environment (40-99)

        Volume-surface ratio: The volume-surface ratio of the structure

        Age of concrete at the beginning of shrinkage: The number of days elapsed after pouring of concrete, when the shrinkage is assumed to start.

        Init Curing Method: Initial curing method

        Concrete Compressive Strength Factor (a,b)

        Material factored ultimate value: The user may enter the ultimate values considering concrete properties by ACI code or User type.  

        Type

        1. • When ACI Code is selected

        Slump

        Fine aggregate percentage

        Air content

        Cement content

        1. • User is selected

        Material factored ultimate creep coefficient (1.3 ~ 4.15): Ultimate creep coefficient considering concrete properties

        Material factored ultimate shrinkage strain: Ultimate shrinkage strain considering concrete properties

          : Produce the auto-calculated time dependent material property in a graph.

         

      •  When PCA(1986) is selected

        Compressive strength of concrete at the age of 28 days

        Ultimate shrinkage strain (500~800)

        Ultimate creep strain (3~5)

        Relative Humidity of ambient environment (40-99)

        Volume-surface ratio: The volume-surface ratio of the structure

        Reinforcement ratio of cross section of column segment

        Modulus of elasticity of steel

          : Produce the auto-calculated time dependent material property in a graph.

         

      •  When Combined (ACI209(1982) & PCA(1986)) is selected

        Compressive strength of concrete at the age of 28 days

        Relative Humidity of ambient environment (40-100)

        Volume-surface ratio: The volume-surface ratio of the structure

        Creep

        Material factored ultimate creep strain: Ultimate creep strain considering concrete properties

        Volume-surface Ratio: Equation for Volume-surface Ratio  

        Loading aged factored (t : loading age): Equation for loading age coefficient  

        Shrinkage

        Material factored ultimate shrinkage strain: Ultimate shrinkage strain considering concrete properties

        Volume-surface Ratio: Equation for Volume-surface Ratio

        Progress of shrinkage with Time

        Reinforced concrete effect by PCA

        Reinforcement ratio of cross section of column segment

        Modulus of elasticity of Steel

          : Produce the auto-calculated time dependent material property in a graph.

         

      •  When INDIA(IRC:18-2000) is selected

        Compressive strength of concrete at the age of 28 days

        Relative Humidity of ambient environment (40-99)

        Notational size of member

        Note

        1. In case the Notational Size of Member (h) for each element is different due to a changing section, ‘h’ for each element needs to be entered in Change Element Dependent Material Property.

        2. In case the Composite Section for Construction Stage is used, ‘h’ for each Part needs to be entered in Composite Section for Construction Stage.

        Age of concrete at the beginning of shrinkage: The number of days elapsed after pouring of concrete, when the shrinkage is assumed to start.

         : Produce the auto-calculated time dependent material property in a graph.

      •  When European is selected

        Characteristic compressive cylinder strength of concrete at the age of 28 days (fck)

        Relative Humidity of ambient environment (40-99)

        Notational size of member

        Note

        1. In case the Notational Size of Member (h) for each element is different due to a changing section, ‘h’ for each element needs to be entered in Change Element Dependent Material Property.

        2. In case the Composite Section for Construction Stage is used, ‘h’ for each Part needs to be entered in Composite Section for Construction Stage.

        Type of Cement

        Type of Code

        Age of concrete at the beginning of shrinkage: The number of days elapsed after pouring of concrete, when the shrinkage is assumed to start.

         : Produce the auto-calculated time dependent material property in a graph.

      • When AS 3600-2009 is selected

        Compressive strength of concrete at the age of 28 days

        Exposure Environment

        Arid

        Interior

        Temperate Inland

        Tropical or Near Coastal

        Hypothetical Thickness

        Note
        1. In case the Hypothtical Thickness of Member (h) for each element is different due to a changing section, 'h' for each element needs to be entered in Change Element Dependent Material Property.
        
        2. In case the Composite Section for Construction Stage is used, 'h' for each Part needs to be entered in Composite Section for Construction Stage.

         

        Drying Basic Shrinkage Strain

         

        Age of concrete at the beginning of shrinkage: The number of days elapsed after pouring of concrete, when the shrinkage is assumed to start.

         

        : Produce the auto-calculated time dependent material property in a graph.

         

      • When AS/RTA 5100.5-2011 is selected

        Compressive strength of concrete at the age of 28 days

        Exposure Environment

        Arid

        Interior

        Temperate Inland

        Tropical or Near Coastal

        Hypothetical Thickness

        Note
        1. In case the Hypothtical Thickness of Member (h) for each element is different due to a changing section, 'h' for each element needs to be entered in Change Element Dependent Material Property.
        
        2. In case the Composite Section for Construction Stage is used, 'h' for each Part needs to be entered in Composite Section for Construction Stage.

         

        Drying Basic Shrinkage Strain

         

        Age of concrete at the beginning of shrinkage: The number of days elapsed after pouring of concrete, when the shrinkage is assumed to start.

         

          : Produce the auto-calculated time dependent material property in a graph.

         

      •  When User Defined is selected

        Creep Function
        Select Creep Function. To add or modify Creep Functions to and from the list, click to prompt the dialog box, "Time Dependent Material (Creep/Shrinkage) Function".

        Loading Age: Assign the age (time) at which the members become subjected to loads (for instance, the number of days after which the formwork and/or shoring is removed after the concrete pour in the case of self weights)

        

        Add the defined Creep Function to the list in conjunction with Loading Age.

        

        Modify Loading Age pertaining to the registered Creep Function.

        

        Delete the registered Creep Function together with Loading Age.

        Shrinkage Strain Function
        Select Shrinkage Function to apply. Click to prompt "Time Dependent Material (Creep/Shrinkage) Function" dialog box to add or delete Shrinkage Function.

        Note. Recommended number of creep/shrinkage functions for accurate results

        In order to obtain accurate creep results, at least 5 creep/shrinkage functions need to be defined with different loading age. Using the defined functions, midas Gen performs linear interpolation during the construction stages. If there was only one creep function defined in the model file, the program could not get the exact results from the linear interpolation.

        In case of creep/shrinkage database such as CEB-FIP, midas Gen internally generates 48 functions with different loading age.