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.
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When CEB-FIP(2010) 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.
Type of aggregate
: Produce the auto-calculated time dependent material property in a graph.Creep Calculation Process
Shrinkage Calculation Process
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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
When ACI Code is selected
Slump
Fine aggregate percentage
Air content
Cement content
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. -
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. -
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. -
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. -
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.
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