Function
Define the time dependent creep and shrinkage material data for concrete. The properties are applied to Construction stage analysis and Heat of hydration analysis.
Call
From the Main Menu select [Properties] tab > [Material Properties] group > [Time Dependent Material] > [Creep/Shrinkage]
Input
Click the Add button to define a new time dependent material property (creep/shrinkage). Click the Modify button and the Delete button to change and delete the data previously entered. Click the Copy button to copy previously entered data.
Name
Enter the name of the material property, which is referred to by Time Dependent Material Link.
Code
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
The Show Result... button : Produce the auto-calculated time dependent material property in a graph.
Creep Calculation Process
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.
The Show Result... button : 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.
The Show Result... button : 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
The Show Result... button : 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
The Show Result... button : 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
The Show Result... button : 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.
The Show Result... button : 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.
The Show Result... button : 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.
The Show Result... button : 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.
The Show Result... button : 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)
The Add Creep Function button
Add the defined Creep Function to the list in conjunction with Loading Age.
The Modify button
Modify Loading Age pertaining to the registered Creep Function.
The Delete button
Delete the registered Creep Function together with Loading Age.
Shrinkage Strain Function
Select Shrinkage Function to apply. Click the [...] button 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, Gen NX 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, Gen NX internally generates 48 functions with different loading age.