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Info

This page is devoted to frequently asked questions (FAQ) related to auto lateral loads.

 On this page:

Table of Contents

Modeling and application

How do I assign wind auto-lateral-load conditions?

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  1. Define the wind auto lateral load.
  2. Assign wind-pressure coefficients using the Assign > Area Loads > Wind Pressure Coefficients option.

Is it possible to apply wind load to

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a specific frame object only?

ANSWER: Yes, wind load may be applied to specific frame objects through the process which follows:

  1. Define a load pattern, designate the type as Wind, and specify the load as an auto-lateral-load pattern, such as with ASCE 7-05.
  2. Select Modify Lateral Load Pattern > Exposure from Frame and Area Objects > Include Frame Objects, and define wind-direction angle, along with other parameters.
  3. Designate the specific frame objects for wind auto-lateral-load application through Assign > Frame Loads > Open Structure Wind Parameters.

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Extended Question: For modeling a Floating Production Storage and Offloading (FPSO) unit as a 3D frame system, how would I apply wind load per BS standard? The Wave Wind form is limited to API standard, and I'm concerned that diaphragm definition would affect analysis.

ANSWER: Two options are available, described as follows:

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  • Alternatively, use dummy area objects to apply wind loads using exposure from area objects. This may be specified using the BS 6399-95 Wind Load Pattern menu.


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Question: Would you please provide an example and diagrams showing how wind auto lateral load is applied given diaphragm and area object exposure?

Answer: OPEN QUESTION

Display

Is it possible to display auto-lateral-load application?

ANSWER: Yes, auto lateral load may be displayed in a tabular format. The seismic auto-lateral-load pattern applied to structural joints, for example, may be reviewed in tabular format under Model Definition > Load Pattern Definitions > Auto Seismic Loads > Table: Auto Seismic Loads to Joints.


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ANSWER 2: Currently, it is not possible to display calculated wind pressures, though users may indirectly verify pressures by creating a test model. Assigning area-object exposure, for example, users may create a model with area objects located at different elevations and supported by lateral springs. Auto-lateral-load application of wind pressure on these area objects would yield spring displacements and reactions which correlate with applied pressure. VERIFY

Formulation

How do I find the period used to calculate the auto-seismic load?

ANSWER: All parameters, including structural period, are reported in the table available through Load Pattern Definitions > Auto Seismic Load.

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Related Incident:

  • Incident 47806: How to display the period used in calculating an auto-seismic load?


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TO DO:

3 incomplete Review this page for technical/program validity