Applies To
	Product(s):	STAAD.Pro
	Version(s):	All
	Environment:	N/A
	Area:	Modeling Solutions
	Subarea:	Loading
	Original Author:	Bentley Technical Support Group

I need to analyse a deck slab for a temperature change of plus or minus 60 degrees F. In addition, there is a temperature gradient of 25 degrees F between the top and bottom surfaces of the slab. How do I do this? The slab has been modelled using plate elements.

Related question :

How would I enter the temperatures in the dialog boxes in the Staad program.

1) Temperature change for axial elongation
2) Temperature differential from top to bottom
3) Temperature differential from side to side (local Z)

Below is my situation:

Inside temperature = 650 DegF
Outside temperature = 50 DegF

I have entered the inputs different ways and could not get the reasonable results that I expect.

Would you advise me how the data should be entered.

Answer :

If we assume that the temperature at the stress-free condition is A, then, the structure must be analysed for 2 conditions, each of which must have its own load case.

Condition 1 :
-------------

a) temperature at the top of concrete reaching (A + 60 + 12.5)
b) temperature at the bottom of concrete reaching (A + 60 - 12.5)

Assuming that your plate elements all have the local Z axis pointing along the global Y direction, you specify this using the syntax

element-list TEMPERATURE 60 25

The first number (60) is equal to the average temperature you want to design for minus the temperature corresponding to the stress-free condition. The second number is the temperature of the top surface (the fiber at the +Z surface) minus the temperature of the bottom surface (fiber at the -Z surface). Hence, it is important that the +Z surface correspond to top-of-deck.

For example,

LOAD 10 TEMPERATURE INCREASE
TEMPERATURE LOAD
501 TO 588 TEMP 60 25

Condition 2 :
-------------

a) temperature at the top of concrete reaching (A - 60 - 12.5)
b) temperature at the bottom of concrete reaching (A - 60 + 12.5)

The syntax for this is

element-list TEMPERATURE -60 -25

For example

LOAD 11 TEMPERATURE DECREASE
TEMPERATURE LOAD
501 TO 588 TEMP -60 -25

Notes
-----

1) The term in the dialog box "Temperature differential from side to side (local Z)" is applicable only for members (line entities used to represent beams, columns, etc.). It is not relevant for plates.

2) For an example problem that illustrates the application of temperature loads on plates, please go to STAAD.Pro Help section Tutorials > T.3 - Analysis of a slab > T.3 Creating the model using the analytical user interface > T.3 Specifying Primary Load Cases.