Loads settings

The procedure for setting the parameters is the same as for other project parameters.

Acceleration of gravity

This parameter defines the acceleration of gravity g. By default g = 9.81 m/s2.

It is used in the following contexts (non exhaustive list):

Wind region

This parameter defines the region where the modelled structure will be located. The region may influence wind loads that the building will be exposed to. The user may choose from three options for this item:

None

There is no wind load applied.

According to code

The wind region is defined according to appropriate national standard.

User defined

The user specifies the height-wind pressure curve. The real load is then defined as a force load but its type must be set to Wind. The load value input by the user then represents the load width.
User defined - more curves

The user specifies more height-wind pressure curves. The real load is then defined as a force load but its type must be set to Wind. The load value input by the user then represents the load width. Each input load has defined a wind pressure curve in its properties.

Wind setup for IBC

If the option According to code is set for IBC code a Wind setup dialog is shown.

Provisions

 Defines if formulas and values are used from provisions ASCE7-05 or provisions ASCE7-10.

Importance factor/Risk category

Defines Importance factor category, value and hurricane regions for ASCE7-05 or Risk category and hurricane regions for ASCE7-10.

Directionality factor

 Defines Directionality factor according to code for selected structure type.
Gust effect factor

Defines Gust effect factor according to code for selected structure type.
Basic wind Defines a basic wind value.
Exposure and Topographic factor Defines Exposure and Topographic factor according to code.
Calculation method Defines a calculation method - All-heights/Low-rise for ASCE7-05 or Directional/Envelope for ASCE7-10.
Enclosure class Defines if building is enclosed, partly enclosed or open.

Library of wind pressures

When the option User defined is selected, it is possible to open [using the three-dot button] the Wind pressure database manager. In this manager the user may input the required wind curves.

Editing dialogue for the input of wind pressure

The Editing dialogue for the input of wind pressure can be opened from the Wind pressure database manager.

This dialogue contains the following controls.

Name

Specifies the name of the wind curve.

Graphical window

The diagram of the defined wind curve is displayed in this small graphical window. The graphical window offers standard functions such as zoom-in and zoom-out, pan, copy to clipboard, save to file. The functions can be accessed through a pop-up menu or using mouse move with the right button held pressed with simultaneously held Ctrl and/or Shift key(s).

Table with curve values

The table contains the values that define the shape of the curve.

Depending on the option in item Input, this table can be "read-only".

Input

User

The curve is defined manually by the user in the table with curve values.

EC-EN

The EC-EN-defined wind curve is used. For this option the table with curve values is "read only".

DIN

The DIN-defined wind curve is used. For this option the table with curve values is "read only".

NEN

The NEN-defined wind curve is used. For this option the table with curve values is "read only".

BS-EN

The BS-EN-defined wind curve is used. For this option the table with curve values is "read only".

Height range

This parameter defines the height range of the curve. This item is accessible only for code-based wind curves. It is disabled for user-input curve.

Edit curve

This button opens a special where the parameters of the code-based curve can be edited. This item is accessible only for code-based wind curves. It is disabled for user-input curve.

OK

Confirms the changes and closes the dialogue.

Cancel

Discards the changes and closes the dialogue.

Note: The defined wind curves can be reviewed and edited also through tree menu function Library >Loads > Wind pressures. This function becomes accessible only if parameter Wind region in the project setup has been set to Library.

Note: For more information about the generation of wind load see chapter Loads > Load generators > Wind generator.

Snow region

This parameter defines the region where the modelled structure will be located. The region may influence snow loads that the building will be subject to. The user may choose from three options for this item:

None

There is be no snow load applied.

According to code

The snow region is defined according to appropriate national standard.

Snow weight

The user specifies the snow weight per square meter. The real load is then defined as a force load but its type must be set to Snow. The load value input by the user then represents the load width.

Note: For more information about the generation of wind load see chapter Loads > Load generators > Snow generator.

Pond load

The Model factor concerns a reduction factor which is used during the calculation of Pond loads.

More specifically, during the deflection calculation of the water accumulation, the stiffness of the structure is divided by this factor.

Note: More information about Pond loads is given in the chapter Loads > Load generators > Pond water.

Seismic combinations

For codes that support seismic load case combinations with concomitant direction components (e.g. Eurocode), the parameter Factor for concomitant components defines the coefficient applied to concomitant direction seismic load cases in a seismic envelope. Typically, with 2 seismic load cases EQX and EQY and Factor for concomitant components = 0.30 (default), the seismic envelope will contain the following combinations:

Note: More information about seismic combinations is given in the chapter Seismic combinations - Eurocode.