RFEM – Online Manual

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RFEM – Online Manual

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11.8.4.1 Flat/Monopitch roof

Flat/Monopitch roof

Figure 11.194 Generate Snow Loads - Flat/Monopitch Roof dialog box

Flat and monopitch roofs are managed together in one dialog box. The shape coefficients for flat roofs or roofs with one-sided inclination are taken into account according to EN 1991-1-3 and DIN 1055-5.

First, define the standard and, if necessary, the National Annex in the Snow Load Parameters dialog section. This specification controls, which individual text boxes can be accessed.

Use the button to open a map where the snow load zone Z can be selected graphically. Based on your specifications, RFEM determines the characteristic value of the snow load sk on the ground, taking account of the the altitude A (sea level).

Use the three check boxes in the Additional Snow Loads dialog section to control if other snow loads should be considered:

    • Snow accumulations because of snow drift
    • Snow overhang on the eave
    • Snow loads on snow guards

Use the button to define the parameters of the snow overhang and snow guard.

If required, you can adjust the exposure coefficient Ce (EN 1991-1-3, Table 5.1) as well as the thermal coefficient Ct (EN 1991-1-3, Clause 5.2 (8)) in the Coefficients dialog section.

Define the Roof Geometry by means of the roof corner nodes A to D in accordance with the dialog graphic. You can also use the button to determine them graphically in the work window. The plane is marked in the selection color. At least three nodes are required to define a plane. The area does not need to be enclosed by lines or members on all sides.

The Position of Drifted Snow Load can be defined via the edge nodes of the roof area.

Specify the load case numbers for the load generation in the Load Case to Generate and Load Case for Drifted Snow Load dialog sections. Snow load cases can be created with the button. If surfaces are available in the model, you can specify whether member or surface loads are generated in the Create Load Type dialog section.

The Load Distribution Type and Remove Influence from dialog sections are described for the Member Loads From Area Load via Plane generator function.

Click the button to open the Settings for Load Generation dialog box (see Figure 11.178).

You can use the button to scale the loads for specific members. Specifications must be entered in a separate dialog box (see Figure 11.187).

After confirming the generator dialog box with [OK], RFEM displays the results of the load generation for all load cases in an overview. This way, the acting area loads can be compared with the converted loads. Before the loads are transferred to RFEM, you can click the button to access the initial dialog box where you can change the parameters of the loads.