slhutzley
Mechanical
- Dec 8, 2021
- 7
ASME B31Ea-2010 Paragraph 3.4 requires that PD/4t + 0.75*(M_sustained + M_seismic)/Z be less than an allowable stress value dependent on the applicable Piping Code (B31.1, B31.3, etc.).
I am trying to understand how to set up load cases (using Caesar II) that correctly calculate the "M_seismic" value in the equation above, which is defined as the "elastically calculated resultant moment amplitude due to seismic load, including inertia and relative anchor movement." The code is requiring us to combine the resultant moment due to inertia forces (Ux, -Ux, Uy, -Uy, Uz, -Uz) with the moment caused by seismic anchor movements, SAM (D1, -D1, D2, -D2, etc.) to compare to the allowable stress.
I am having trouble understanding how to correctly isolate the terms and combine them to meet ASME B31Ea requirements. I contacted Hexagon, but am still searching for a solution I'm comfortable with. I would greatly appreciate any help in how to properly set up these load cases in Caesar-II. The Caesar-II help directory does not discuss ASME B31E, though the representative at Hexagon says that they are working on a method to accommodate it. Until then, I am asking for your help.
I am trying to understand how to set up load cases (using Caesar II) that correctly calculate the "M_seismic" value in the equation above, which is defined as the "elastically calculated resultant moment amplitude due to seismic load, including inertia and relative anchor movement." The code is requiring us to combine the resultant moment due to inertia forces (Ux, -Ux, Uy, -Uy, Uz, -Uz) with the moment caused by seismic anchor movements, SAM (D1, -D1, D2, -D2, etc.) to compare to the allowable stress.
I am having trouble understanding how to correctly isolate the terms and combine them to meet ASME B31Ea requirements. I contacted Hexagon, but am still searching for a solution I'm comfortable with. I would greatly appreciate any help in how to properly set up these load cases in Caesar-II. The Caesar-II help directory does not discuss ASME B31E, though the representative at Hexagon says that they are working on a method to accommodate it. Until then, I am asking for your help.
