This cosine curve has the form :Įlev is the elevation of a point lying on the surface representing tank base after rigid body tilt has occurred, theta is angular coordinate of the point, and a, b, and c are fitting parameters to be estimated. It is defined as the vertical distances between the irregular curve and the cosine curve representing the magnitudes of the out-of-plane settlements. To accurately calculate the out of plane settlement, this component should be removed from the settlements measurements.Ĭ) Out of plane settlement: Also known as differential settlement, this component is the most important one and should be taken into account, since it causes internal stresses in the structural parts of tanks. Again, it does not introduce any internal stresses in the tank shell. The uniform settlement is to be taken out from the measured settlements.ī) Rigid body tilt: This results from a tilt in whole structure without any internal deformations in the structure as a rigid body movement. However, the all connections should be taken care of to accommodate this settlement.
This is the least important component, since it does not introduce any stress in the tank structure.
Typical steel storage tanks Components of settlementsĪs per Appendix B of API 653 settlement of tank shell is a combination of several components as follows:Ī) Uniform settlement: As the name implies, the whole tank and its components undergo a settlement whose value is the same for all points on foundation plane.
0 kommentar(er)
