CASO DE EJEMPLO: SOLICITUD DE CRÉDITO

Activate by double-clicking the Nozzles check box on the Pipe Element Spreadsheet and selecting the API 650 radio button from the Nozzle Auxiliary Data field. Deactivate by double-clicking the check box a second time.

CAESAR II can also calculate nozzle flexibilities according to appendix P of API 650,

"Design of Carbon Steel Atmospheric Oil Storage Tanks."

Nozzle Node Number

Node that is located at the nozzle's intersection with the vessel shell. There should only be a single piping element connected to this node, and there should be no restraints acting on the node. The nozzle element should be perpendicular to the vessel shell. Hillside nozzles and latrolets can still be modeled; however, the first (possibly very short) nozzle element that comes from the vessel should be perpendicular to the vessel to keep the local stiffness properly oriented. The second, longer nozzle element can then go off on the true centerline of the nozzle.

Tank Node Number

Node on the tank surface at the point where the nozzle intersects the vessel/tank shell. The tank node is optional, and if not given the nozzle node is connected via the API stiffnesses to a point fixed rigidly in space. If the tank node is given, the nozzle node will be connected via the API stiffnesses to the tank node. Tank nodes are specified

foundation.

Nozzle Diameter

Outside diameter of the nozzle. (Does not have to be equal to the diameter of the pipe used to model the nozzle.)

Nozzle Wall Thickness

Wall Thickness of the nozzle. May be different than the attached pipe wall thickness

API-650 Tank Diameter

Outside Diameter of the Vessel or API 650 storage tank. Note that API 650 Addendum 1 does not recommend these computations for diameters less than 120 feet.

API-650 Tank Wall Thickness

Wall Thickness of the Vessel at the point where the Nozzle connects to the vessel. DO NOT include the thickness of any

reinforcing pad.

API 650 Reinforcing 1 or 2

For API tanks, if the reinforcing is on the shell, then enter 1. If it is on the nozzle, enter a 2.

API 650 Nozzle Height

For API 650 applications, enter the height from the centerline of the nozzle to the base of the tank.

API 650 Fluid Height

Enter the liquid level of the fluid in the storage tank. This fluid level must be greater than the nozzle height.

API 650 Specific Gravity

Enter the specific gravity of the stored liquid. This value is unit less. API-650 Tank Coefficient of Thermal Expansion Enter the coefficient of thermal expansion of the plate material of the tank is constructed. Values are listed in engineering handbooks or the appropriate section of the API 650, App P. If this value is left blank, zero will be assumed.

Enter the change in temperature from ambient to its maximum that the tank normally experiences. For example: If the maximum summertime temperature is 107°F. The delta T would be 107 - 70 = 37°F. If this value is left blank, zero will be assumed.

API-650 Tank Modulus of Elasticity

For API 650 nozzles, the hot modulus of elasticity of the tank must be entered directly. If this value is left blank, 29.5E6 will be assumed.

PD 5500 Nozzles

Activate by double-clicking the Nozzles check box on the Pipe Element Spreadsheet and selecting the PD 5500 radio button from the Nozzle Auxiliary Data field. Deactivate by double- clicking the check box a second time.

CAESAR II can also calculate nozzle flexibilities according to Appendix G of the PD 5500 Specification for Unfired Fusion Welded Pressure Vessels. The input requirements for these nozzles are:

Nozzle Node Number

Node that is located at the nozzle's intersection with the vessel shell. There should only be a single piping element connected to this node, and there should be no restraints acting on the node. The nozzle element should be perpendicular to the vessel shell. Hillside nozzles and latrolets can still be modeled; however, the first (possibly very short) nozzle element that comes from the vessel should be perpendicular to the vessel to keep the local stiffness properly oriented. The second, longer nozzle element can then go off on the true centerline of the nozzle.

Node on the vessel/tank surface at the point where the nozzle intersects the vessel shell. The vessel/tank node is optional, and if not given the nozzle node is connected via the stiffnesses to a point fixed rigidly in space. If the vessel node is given, the nozzle node will be connected via the stiffnesses to the vessel node. Vessel nodes are specified when the user wishes to model through the vessel from the nozzle connection to the skirt or foundation.

Vessel Type - Cylinder (0) or Sphere (1)

If the vessel is cylindrical, enter a 0. For cylinders, the distances to stiffeners/heads and the vessel direction cosines are required. If the vessel is spherical, enter a 1. For spheres, the fields for the distances to stiffeners/heads and vessel direction cosines are both ignored.

Nozzle Diameter

Outside diameter of the nozzle. (Does not have to be equal to the diameter of the pipe used to model the nozzle.)

Vessel Diameter

Outside diameter of the vessel.

Vessel Wall Thickness

Wall thickness of the vessel at the point where the nozzle connects to the vessel. Do not include the thickness of any reinforcing pad.

Vessel Reinforcing Pad Thickness

Thickness of any reinforcing pad at the nozzle this thickness is added to the vessel wall thickness before nozzle stiffness calculations are performed.

Distance to Stiffener or Head

Distance along the vessel center-line, from the center of the nozzle opening in the vessel shell to the closest stiffener or head in the vessel that significantly stiffens the cross-section of the vessel against local deformation normal to the shell surface.

Distance to Opposite-Side Stiffener or Head

Distance from the center of the nozzle opening in the vessel shell to the closest stiffener or head in the vessel on the other side of the nozzle. This entry is ignored for spherical vessels.

These are direction vectors or direction cosines that define the center-line of the vessel. For a horizontal vessel aligned with the “X” axis, this entry would read:

Vessel centerline direction vector X ... 1.0 Vessel centerline direction vector Y ... <Blank> Vessel centerline direction vector Z ... <Blank>

Note: The centerlines of the nozzle and vessel cannot be co-linear or CAESAR II will flag this as an error. This entry is ignored for spherical vessels.

Displacements

Activate by double-clicking the Displacements check box on the Pipe Element Spreadsheet. Deactivate by double clicking the Displacements check box a second time.

This auxiliary screen is used to enter imposed displacements for up to two nodes per spreadsheet. Up to nine displacement vectors may be entered (load components D1 through D9). If a displacement value is entered for any vector, this direction is considered to be fixed for any other non-specified vectors.

Note Leaving a direction blank for all nine vectors models the system as being free to move in that direction. Specifying “0.0” implies that the system is fully restrained in that direction.

 _{Enter the node number where the displacement is to be specified. There must} not be a restraint at this node.

 _{Enter the displacements at the node. Any displacement direction not specified} for any displacement vector will be free.

 _{To specify an anchor at Node 50 with a displacement of 0.25 in. in the +X , 0.10} in. in the +Y , and 0.08 in. in the –Z , for displacement vector #1, enter data as shown in the Figure above.

 _{The displacements at a node can be specified for up to 9 different vectors,} intended to correspond to the 9 temperature cases.

degree-of-freedom will be considered restrained for all load cases whether or not they contain that displacement set.

Forces & Movements

Activate by double-clicking the Forces/Moments check box on the Pipe Element Spreadsheet. Deactivate by double clicking the check box a second time.

This auxiliary screen is used to enter imposed forces and/or moments for up to two nodes per spreadsheet. Up to nine force vectors may be entered (load components F1 through F9).

Uniform Loads

Activate by double-clicking the Uniform Loads check box on the Pipe Element Spr eadsheet. Deactivate by double clicking the check box a second time.

This auxiliary screen is used to enter up to three uniform load vectors (load components U1, U2 and U3). These uniform loads are applied to the entire current element, as well as all subsequent elements in the model, until explicitly changed or zeroed out with a later entry.

This auxiliary screen is used to specify whether this portion of the pipe is exposed to wind or wave loading. (Note that the pipe may not be exposed to both.) Selecting Wind exposes the pipe to wind loading; selecting Wave exposes the pipe to wave, current, and buoyancy loadings; selecting Off turns off both types of loading. This screen is also used to enter the Wind Shape Factor (when Wind is specified) and various wave coefficients (if left blank they will be program-computed) when Wave Loading is specified. Entries on this auxiliary screen apply to all subsequent piping, until changed on a later spreadsheet.

Note Specific wind and wave load cases are built using the Static Load Case Editor.

There are three different methods that can be used to generate wind loads on piping systems:

 _{ASCE #7 Standard Edition, 1995}

 _{User entry of a pressure vs. elevation table}  _{User entry of a velocity vs. elevation table}

The appropriate method is selected by placing a value of 1.0 in one of the first three boxes.When defining a pressure or velocity vs. elevation table the user needs to specify only the method and the wind direction on the preceding screen. Upon pressing the User Wind Profile button, the user is prompted for the corresponding pressure or velocity table. If a uniform pressure or velocity is to act over the entire piping system, then only a single entry needs to be made in the table, otherwise the user should enter the pressure or velocity profile for the applicable wind loading.

Note To use the ASCE #7 wind loads, all of the fields should be filled in.

For example, as per ASCE #7, the following are typical basic wind-speed values: California and West Coast Areas- 124.6 ft. /sec. ( 85 m.p.h.)

Great Plains- 132.0 ft ./sec ( 90 m.p.h.)

Non-Coastal Eastern United States- 132.0 ft./sec ( 90 m.p.h.) Gulf Coast- 190.6 ft. /sec (130 m.p.h.)

Florida-Carolinas- 190.6 ft./sec (130 m.p.h.) Miami- 212.6 ft. /sec (145 m.p.h.)

New England Coastal Areas- 176.0 ft. /sec (120 m.p.h.)

Wave Load

Drag Coefficient, Cd

Coefficient as recommended by API RP2A. Typical values range from 0.6 to 1.20. Entering a 0.0 instructs CAESAR II to calculate the drag coefficient based on particle velocities.

Added Mass Coefficient, Ca

This coefficient accounts for the added mass of fluid entrained into the pipe. Typical values range from 0.5 to 1.0. Entering a 0.0 instructs CAESAR II to calculate the added mass coefficient based on particle velocities.

Lift Coefficient, Cl

This coefficient accounts for wave lift, which is the force perpendicular to both the element axis and the particle velocity vector. Entering a 0.0 instructs CAESAR II to calculate the added lift coefficient based on particle velocities.

Marine Growth

The thickness of any marine growth adhering to the external pipe wall. This will increase the pipe diameter experiencing wave loading by twice this value.

Marine Growth Density

An entry in this field designates the density to be used if including the weight of the marine growth in the pipe weight. If left blank, the weight of the marine growth will be ignored.

This selection turns off both wind and / or wave loads from this point forward in the model.

Up to four different hydrodynamic load cases may be specified for any one job. Several hydrodynamic coefficients are defined on the element spreadsheet. The inclusion of hydrodynamic coefficients causes the loads WAV1, WAV2, WAV3, and WAV4 to be available in the load case editor.

A CAESAR II Hydrodynamic Loading dialog is shown in the following figure. In the load case editor, four different wave load profiles can be specified. Current data and wave data may be specified and included together or either of them may be omitted so as to exclude the data from the analysis. CAESAR II supports three current models and six wave models. See the CAESAR II Technical Reference Manual for a detailed discussion of hydrodynamic analysis.