Coefficient of Thermal Expansion in Road/Rail Crossing Calculations

[spipeliner]

API 1102 does not specify a value for coefficient of thermal expansion. It specifies a typical range of 1.6x10-5 to 1.9x10-5 (refer to Table A-2).

Clause 832.2 of ASME B31.8 states that “The thermal expansion and contraction of the more common carbon and low alloy steels may be calculated using 6.5 x 10−6 in./in./°F (1.17 x 10−5cm/cm/°C) as the coefficient of thermal expansion”. Also Clause 402.2.1 of ASME B31.4 states that “The linear coefficient of thermal expansion for carbon and low alloy high tensile steel may be taken as 6.5 x 10-6 in./in./°F for temperatures up to 250°F (11.7 x 10-6 mm/mm/°C for temperatures up to 120°C).

Both ASME B31.8 and ASME B31.4 recommend to use 11.7 x 10-6 mm/mm/°C as the coefficient of thermal expansion, but this is outside the range that is specified in API 1102.

What value for coefficient of thermal expansion should be used in road/railroad crossing calculation?

 

[BigInch]

API is a recommended practice, so even it's use is not exactly mandatory. In the general sense, whenever you have a "real" value, you should use it (with a good dose of your engineering judgement). In this case use 0.0000065 in/in-F.

"People will work for you with blood and sweat and tears if they work for what they believe in......" - Simon Sinek

 

[spipeliner]

Thanks BigInch. That was very helpful.