B31.1 piping code updated to 2001. B31.1 material properties are not yet updated.

For the European piping code EN 13480, the tensile strength (Rm) can be input for a material which is used in calculating fc in Eqn (12.1.3-2).

For piping code = none, the SIF for a bend of less than 90 deg is interpolated as follows:

A scalar multiplier for the B31 90 deg bend SIF can be developed based on ASME/BPVC Section III, Division 1, Case N-319-2, "Alternate Procedure for Evaluation of Stresses in Butt Welding Elbows in Class 1 Piping" which provides rules for bending stress indices for curved pipe of arc lengths between 0 and 180 deg. The in-plane stress indices for varying arc length from Case N-319 are:

C(2z) = 1.95/h^(2/3) for bend angles of 90 deg or greater [Note, the index is approximately 2 times the B31 90 deg elbow SIF, i.e., the difference between "design by rule" (B31/effective) stresses and "design by analysis" (theoretical) stresses.]

C(2z) = 1.75/h^(0.56) for a bend angle of 45 deg

C(2z) = 1.0 for a bend angle of 0 deg (straight pipe)

The Case states the stress index may be interpolated between bend angles. Thus, a 45 deg bend SIF could be reasonably estimated to be the B31 SIF multiplied by C(2z) for a 45 deg bend divided by C(2z) for a 90 deg bend. Other bend angle SIF's could be interpolated between the given C(2z)'s.

[Note, however, the effect of arc length will likewise alter bend stiffness which this does not address.]

For other piping codes, the SIF interpolation will be implemented as an option in a future version.

Bug correction: For ASME(1986) and ASME(1992) the butt weld SIF was calculated according to ASME 1980.

Bug correction: Hanger loads were not calculated correctly for hydrotest case.

Bug correction: Beam sections were not converted properly from version 3.71.

Bug correction: Spectrum library was not read properly if it was written in versions 5.1 upto 5.1I.