Function
- Enter the temperature differences between specific locations of beam for thermal stress analysis. The vertical temperature gradient is considered in concrete and steel superstructures with concrete decks, which are subject to temperature difference due to direct sun light and shade.
- In addition to this feature, there is also the "Temperature Gradient" feature, which allows for implementing temperature variations within a cross-section.
- A temperature difference may be also defined by the Temperature Gradient function. In case of Temperature Gradient, only the temperature difference between the top and bottom of a section can be entered. However, in case of Beam Section Temperature, temperature differences for certain locations in a section can be entered.
- The "Beam Section Temperatures" feature is primarily used to input temperature differences in rectangular beam elements.
General Type : If a section for which a temperature difference is considered is not a rectangle, the section should be transformed into an equivalent rectangular section, which produces the identical moment due to the temperature load. And then the user needs to input the width and height of the equivalent rectangular section.
PSC/Composite Type : For PSC sections (except for Value type PSC sections) and Composite sections, which are relatively complex but frequently used, the program automatically defines the temperature load by dividing and transforming the corresponding zone. In case of PSC section as shown in the figure above, the transformed rectangular zone can be automatically calculated by selecting the PSC/Composite option instead of manual calculation.
Call
From the main menu, select [Load] tab > [Type : Temperature] > [Temperature Loads] group > [Beam Section Temp.]
Input
Load Case Name
Assign the load case name. Click the ... button to the right to enter additional load cases and modify or delete existing load cases.
Load Group Name
Select the desired Load Group Name. Click the ... button to the right to enter additional load group names and modify or delete existing load group names.
Options
Add : To enter new or additional partial temperature loads to beam elements
Replace : To replace previously entered temperature loads
Delete : To delete previously entered temperature loads
Section Type
General : Select when inputting the temperature difference between the top and bottom of a General Section.
If the section for which the temperature difference is to be considered is not a square, the section should be transformed into an equivalent square section having the same area and centroid as the original section.
PSC/Composite : Select when inputting a temperature difference in a PSC section type beam element.
In case of General Type
In case of General Section Type
Direction
Local-y : Temperature difference in the direction of ECS y-axis
Local-z : Temperature difference in the direction of ECS z-axis
Ref. Position
Assigns a reference position in the beam. The distance 'H' is measured from this reference position, and the temperature load is assumed to be applied at location 'H'.
Centroid : Centroid in the beam
+ End(Top) : The upper extreme fiber of the beam
- End(Bot.) : The lower extreme fiber of the beam
Section Temperature
Initial Temperature
Specify the initial temperature in Structure Type.
Material
Define the material properties of the beam elements.
Element : Apply the material property information of the selected beam elements.
Input : Define the material properties to be applied to the thermal stress analysis.
Elast. : Modulus of elasticity
Therm. : Thermal expansion coefficient
B : Width being considered for temperature difference. If a section for which the temperature difference is to be considered is not a rectangle, the section needs to be transformed into an equivalent rectangular section.
H1, H2 : Distance from the Ref. Position to the locations where the temperatures are defined
T1, T2 : Temperatures at H1 and H2 respectively
Click the Add button to add the input data to the list. To modify the data, click the Modify button after selecting and revising the relevant data. the Delete button is used to delete the data.
When a temperature load is applied linearly to structural elements, self-restrained stresses do not occur. However, if a nonlinear temperature load is applied to structural elements, self-restrained stresses may take place. Such internal retrained stresses occur without the presence of external restraints causing residual stresses internally.
In case of PSC/Composite Type
In case of PSC/Composite Type
Apply by Code Provision
Check on this option to apply temperature gradient to the section according to the code provision. PSC, composite PSC and composite steel section are supported depending on the selected code. General sections imported from SPC are not supported.
SNiP / SP
Composite steel section is only supported.
IRC6: 2017
As per IRC6:2017, the user can provide the temperature gradient for PSC and Steel Composite girders for the positive and the reverse temperature difference.
(1) Temperature Gradient (Positive/Reverse) for Concrete sections
(2) Temperature Gradient (Positive/Reverse) for Steel Composite sections
AASHTO LRFD 2020
As per 3.12.3 of AASHTO LRFD, the user can provide the temperature gradient for PSC and Steel Composite girders for the positive and the negative temperature difference.
(1) Temperature Gradient (Positive/Negative) for Concrete sections
(2) Temperature Gradient (Positive/Negative) for Steel Composite sections
Eurocode
As per 6.1.4.2 of EN 1991-1-5: 2003, the user can provide the temperature gradient for PSC and Steel Composite girders for the heating and the cooling temperature difference.
(1) Temperature Gradient (Heating/Cooling) for Concrete sections
(2) Temperature Gradient (Heating/Cooling) for Steel Composite sections
AS 5100
As per 18.3 of AS 5100.2: 2017, the user can provide the temperature gradient for PSC and Steel Composite girders for the positive and the negative temperature difference.
(1) Temperature Gradient (Positive/Negative) for Concrete sections
(2) Temperature Gradient (Positive/Negative) for Steel Composite sections
Section Temperature
Initial Temperature
Specify the initial temperature in Structure Type.
Material
Define the material properties of the beam elements.
Element : Apply the material property information of the selected beam elements.
Input : Define the material properties to be applied to the thermal stress analysis.
Elast. : Modulus of elasticity
Therm. : Thermal expansion coefficient
Ref : Select a reference position at which the temperature load is acting. The distance 'H' is defined from this reference position to the position at which the temperature load is acting.
B : Width being considered for temperature difference. For Value type PSC section, the user should manually input the width of the equivalent square section. For other PSC and Composite sections, width shall be automatically calculated.
H1, H2 : Distance from the Ref. Position to the locations where the temperatures are defined. Enter the distance directly or specify the distance using Shear Check positions (Z1, Z2 & Z3) in Section.
T1, T2 : Temperatures at H1 and H2 respectively
position of Z1 in Section
Click the Add button to add the input data to the list. To modify the data, click the Modify button after selecting and revising the relevant data. The delete button is similarly used.
When a temperature load is applied linearly to structural elements, self-restrained stresses do not occur. However, if a nonlinear temperature load is applied to structural elements, self-restrained stresses may take place. Such internal retrained stresses occur without the presence of external restraints causing residual stresses internally.
Calculation of Beam Section Temperatures in PSC Section and Composite Section (Composite T, Composite I)
Divide the section to which the temperature load is applied into ten segments (Max. height = 0.1m). Here, the section must be divided at curved positions, boundary of the Part and boundary between Flange and Web in the composite section as shown in the figure below. Calculate property of each segment using the same procedure performed in General Type. The top and bottom of the segment rectangle corresponds to H1 and H2 in the General Type, respectively. The temperature of each segment is calculated assuming that the temperature load applied at T1 and T2 varies linearly. The final result is calculated by combining the results from each segment. This is equivalent to applying the temperature load ten times in the original method.