Axial force due to thermal effects

[clarke1973]

Can anyone give me a formula (or method) for calculating the axial force in a steel member for a known temperature variation in degree celcius?

thanks in advance

 

[Joel900]

The force will be dependent on boundary conditions. If the steel member is not restrained against movement, the member will expand and no force will be generated.

 

[clarke1973]

thanks for your response.
the steel members will be restrained against movement. I have a large steel framed shed to design in the middle east, with limited opportunities for movement joints. local guidelines state I need to allow for a temperature variation of + or - 35 deg celcius

 

[Antnyt23]

I believe table 17-11 of the steel manual (14th edition, may be different if you have an older manual) gives you some information on thermal expansion and the steel coefficients. Let me know if that is what you are looking for Clarke. It has some short examples also that should help.

 

[canwesteng]

Find thermal strain from thermal expansion coefficient. Calculate resulting stress using young's modulus. Pretty straight forward. Look out for members not designed for large axial tensions, such as beams, with connections not suitable for these stresses. The beam is more than likely okay, but the connection may fail. Is the variation +/- 35 degrees (ie. steel may be installed at 0 and temp may reach 35, or steel may be installed at 35 and temp may reach 0), or from +35 to - 35 (ie steel could be installed at -35 and reach +35)?

 

[clarke1973]

the temperature variation is an increase i.e steel installed at 15 degrees and the temp may reach 50...

thanks for the feedback

 

[jayrod12]

The force generated is the same force that would cause elastic shortening of the member equal to the temperature elongation and then back calculate. Something along the lines of dL=PL/(AE). where dL is your expected temperature elongation. AT least this is a reasonable approximation.