Criteria for selection of lines for Wind Analysis:⬇️
Criteria should be mentioned in ITB document. As a guideline the following can be followed after verification from client:
• Lines with outside diameter 12” and larger (including insulation) running on 10 m and above.
• Steam / Flare header on the pipe rack.
• Other lines considered important as per stress engineer’s decision.
However if lines are covered by some shelter or other structures then wind analysis can be ignored for those lines.
Criteria should be mentioned in ITB document. As a guideline the following can be followed after verification from client:
• Lines with outside diameter 12” and larger (including insulation) running on 10 m and above.
• Steam / Flare header on the pipe rack.
• Other lines considered important as per stress engineer’s decision.
However if lines are covered by some shelter or other structures then wind analysis can be ignored for those lines.
Data Required for Wind Analysis:⬇️
For wind analysis you must have following data from the client.
• Wind shape factor: Normally for pipe elements the data varies from 0.6-0.8. Check in ITB what value it says to use.
• Pressure Vs Elevation Profile: Sometimes client provides this profile directly and sometimes provides equation and data to calculate the profile. A typical wind profile will be shown in diagram while explaining the steps required while analyzing using Caesar II.
• Elevation of the line under analysis. If HPP elevation is other than 0 you have to reduce HPP from line global elevation to get actual elevation.
For wind analysis you must have following data from the client.
• Wind shape factor: Normally for pipe elements the data varies from 0.6-0.8. Check in ITB what value it says to use.
• Pressure Vs Elevation Profile: Sometimes client provides this profile directly and sometimes provides equation and data to calculate the profile. A typical wind profile will be shown in diagram while explaining the steps required while analyzing using Caesar II.
• Elevation of the line under analysis. If HPP elevation is other than 0 you have to reduce HPP from line global elevation to get actual elevation.
What to check:⬇️
As per code B 31.3 we have to check code compliance of the calculated stress (Sustained +Wind). The allowable stress for wind analysis is 1.33 times Sh values. However sometimes client requires to check the nozzle loading in Operating+ Wind cases (W+T+P+Win) for static equipment. Normally client does not require wind load checking for rotating equipment.
As per code B 31.3 we have to check code compliance of the calculated stress (Sustained +Wind). The allowable stress for wind analysis is 1.33 times Sh values. However sometimes client requires to check the nozzle loading in Operating+ Wind cases (W+T+P+Win) for static equipment. Normally client does not require wind load checking for rotating equipment.
Steps for Static Analysis in Caesar II:⬇️
Most of the steps are mentioned in attached images. All are self explanatory.
• Model the piping system under analysis from piping isometric drawings.
• Enter elevation of the first node in global coordinates.
• Click on Wind/Wave check box on Caesar II Spreadsheet and mention wind shape factor as shown in Fig. 1
Most of the steps are mentioned in attached images. All are self explanatory.
• Model the piping system under analysis from piping isometric drawings.
• Enter elevation of the first node in global coordinates.
• Click on Wind/Wave check box on Caesar II Spreadsheet and mention wind shape factor as shown in Fig. 1
• Now run the analysis and go to the load case editor and select Pressure Vs Elevation as shown in Fig. 2
• In next step enter the pressure vs elevation profile in consistent unit and enter wind direction cosines as shown in Fig. 3. Normally wind analysis is performed considering wind flow from North, South, East and West direction. Accordingly Enter +1 or -1 in X or Z direction. Wind analysis is generally not considered in vertical direction.
• Refer Fig. 4 and prepare the highlighted load cases additionally for wind analysis. Load cases for L17 to L20 are for code compliance checking and load cases from L5 to L8 for support and Nozzle load checking.
• Refer Fig 5 and make the combination method as scalar or absolute for the shown load cases.
• In the final stage run the analysis and check results. If failing make suitable adjustments to qualify the same.
Pipe Design mainly depends upon stress analysis.
Process piping and power piping are typically checked
by pipe stress engineers to verify that the routing,
nozzle loads, hangers, and supports are properly placed
and selected such that allowable pipe stress is not
exceeded under different loads such as sustained loads,
operating loads, pressure testing loads, etc., as
stipulated by the ASME B31, EN 13480 or any other
applicable codes and standards. It is necessary to
evaluate the mechanical behavior of the piping under
regular loads (internal pressure and thermal stresses) as
well under occasional and intermittent loading cases
such as earthquake, high wind or special vibration, and
water hammer. This evaluation is usually performed
with the assistance of a specialized (finite element) pipe
stress analysis computer program.
CAESAR II is a complete pipe stress analysis software
program that allows quick and accurate analysis of
piping systems subjected to weight, pressure, thermal,
seismic and other static and dynamic loads. It can
analyze piping systems of any size or complexity.
CAESAR II is unique, incorporating calculation
methods and analysis options not found in any other
program. It provides for the static and dynamic analysis
of piping systems. Calculation capabilities include:
(i) fiber reinforced plastic
(ii) buried piping
(iii) wind, wave and earthquake loading
(iv) expansion joints
(v) valves, flanges and vessel nozzles
(vi) piping components
(vii) nozzle flexibilities
Process piping and power piping are typically checked
by pipe stress engineers to verify that the routing,
nozzle loads, hangers, and supports are properly placed
and selected such that allowable pipe stress is not
exceeded under different loads such as sustained loads,
operating loads, pressure testing loads, etc., as
stipulated by the ASME B31, EN 13480 or any other
applicable codes and standards. It is necessary to
evaluate the mechanical behavior of the piping under
regular loads (internal pressure and thermal stresses) as
well under occasional and intermittent loading cases
such as earthquake, high wind or special vibration, and
water hammer. This evaluation is usually performed
with the assistance of a specialized (finite element) pipe
stress analysis computer program.
CAESAR II is a complete pipe stress analysis software
program that allows quick and accurate analysis of
piping systems subjected to weight, pressure, thermal,
seismic and other static and dynamic loads. It can
analyze piping systems of any size or complexity.
CAESAR II is unique, incorporating calculation
methods and analysis options not found in any other
program. It provides for the static and dynamic analysis
of piping systems. Calculation capabilities include:
(i) fiber reinforced plastic
(ii) buried piping
(iii) wind, wave and earthquake loading
(iv) expansion joints
(v) valves, flanges and vessel nozzles
(vi) piping components
(vii) nozzle flexibilities
Data Input:⬇️
CAESAR II makes it easy to input and
display all the data needed to accurately define a piping
system analysis model. Input can be accessed or
modified on an element-by-element basis, or datasets
can be selected to make global changes.
CAESAR II makes it easy to input and
display all the data needed to accurately define a piping
system analysis model. Input can be accessed or
modified on an element-by-element basis, or datasets
can be selected to make global changes.
Cutting-edge Graphics:⬇️
The CAESAR II input graphics module makes quick work of developing
analysis models while clearly indicating areas of concern and providing an excellent idea of the piping system's flexibility. Color-coded stress models and animated displacements for any stress load case are available.
The CAESAR II input graphics module makes quick work of developing
analysis models while clearly indicating areas of concern and providing an excellent idea of the piping system's flexibility. Color-coded stress models and animated displacements for any stress load case are available.
Design Tools and Wizards:⬇️
Tools and wizards for
tasks such as creating expansion loops or viewing plant
models in the analysis space help bridge the gap
between knowledge and experience. Such tools take the
guess work out of producing accurate analysis and
recommending practical design changes. Nonlinear
effects such as support lift off, gap closure and friction
are also included. CAESAR II also selects the proper
springs for supporting systems with large vertical
deflections. Dynamic analysis capabilities include
modal, harmonic, response spectrum and time history
analysis.
Tools and wizards for
tasks such as creating expansion loops or viewing plant
models in the analysis space help bridge the gap
between knowledge and experience. Such tools take the
guess work out of producing accurate analysis and
recommending practical design changes. Nonlinear
effects such as support lift off, gap closure and friction
are also included. CAESAR II also selects the proper
springs for supporting systems with large vertical
deflections. Dynamic analysis capabilities include
modal, harmonic, response spectrum and time history
analysis.
Analysis Options: ⬇️
Besides the evaluation of a piping
system's response to thermal, deadweight and pressure
loads, CAESAR II analyzes the effects of wind, support
settlement, seismic loads and wave loads.
Besides the evaluation of a piping
system's response to thermal, deadweight and pressure
loads, CAESAR II analyzes the effects of wind, support
settlement, seismic loads and wave loads.
Error Checking and Reports: ⬇️
The CAESAR II program includes an integrated error checker. This error
checker analyzes the user input and checks for consistency from both a "finite element" and "piping" point of view. Reports are clear, accurate concise and fully user definable.
The CAESAR II program includes an integrated error checker. This error
checker analyzes the user input and checks for consistency from both a "finite element" and "piping" point of view. Reports are clear, accurate concise and fully user definable.