Eurocode ENV1991-2-4:1995

Setting	Description
Load Case	States the Label of the load case being defined.
Terrain	From the drop-down list, select the category that best describes the level of wind obstruction of the given terrain. Refer to Table 8.1 of ENV 1991-2-4:1995 in section 8.3 for more information.
Direction	Use the Direction box to indicate the direction of the force (X, Y, or both) by clicking on the corresponding box so that the box is marked. One load case will be generated for each direction at which the force acts.
Mean Roof Height/Structure Height	Building height used in the calculation of Gust Response and Pressure Coefficients (It is not used in the calculation of the actual exposed area). Building Height refers to the height of the building above ground level as defined in the Ground Level dialog. If parapet height is to be included, it is defined in the Exposure dialog. You have the option to override the program’s selection of Building Height by selecting the third option, Use, and entering a value in the corresponding edit box. See building code for more information.
Reference Wind Velocity	The reference wind velocity is the product of: The Basic wind velocity, the Direction Factor (Cdir), the Seasonal Factor (Ctem), and the Altitude Factor (Calt). Refer to the local code and the Eurocode for more information on the appropriate magnitude of these values
Cpe Coefficient	The Cpe coefficient is calculated based on the dimensions provided by the engineer. Note: The Cpe value is applied throughout the entire height of the structure and does not adjust at each story according to the story dimensions.
Building Dimensions	This is the dimension used to calculate the external pressure coefficient, Cpe. The default values are the dimensions of the building at the ground level.
Generate Additional Load Cases for Analysis with Tension-Only Members	RAM Frame utilizes a nonlinear analysis algorithm to keep track of tension-only members during solution of the structural model under applied loads. Since the process has a nonlinear (iterative) nature, analysis results can not be simply superposed with other results as in load combination option in RAM Frame. Therefore, each lateral load case (wind or seismic) are solved separately. Since the direction of the lateral loads become important in an iterative analysis, RAM Frame provides an option such that additional load cases can be created upon user request. When Generate Additional Load Cases for Analysis with Tension-Only Members in generating lateral load cases (wind and seismic load cases only) is invoked, additional load cases are created. For instance, there are 12 load cases generated for a regular IBC 2000 (ASCE 7-98) Wind load case. If this box is checked, the number of the load cases becomes 22. Additional load cases are created to account for directional effects of applied loads so that the most severe loading case is captured. Conceptual example of additional load cases for tension-only members

Load Case

States the Label of the load case being defined.

Terrain

From the drop-down list, select the category that best describes the level of wind obstruction of the given terrain. Refer to Table 8.1 of ENV 1991-2-4:1995 in section 8.3 for more information.

Direction

Use the Direction box to indicate the direction of the force (X, Y, or both) by clicking on the corresponding box so that the box is marked. One load case will be generated for each direction at which the force acts.

Mean Roof Height/Structure Height

Building height used in the calculation of Gust Response and Pressure Coefficients (It is not used in the calculation of the actual exposed area). Building Height refers to the height of the building above ground level as defined in the Ground Level dialog. If parapet height is to be included, it is defined in the Exposure dialog.

You have the option to override the program’s selection of Building Height by selecting the third option, Use, and entering a value in the corresponding edit box.

See building code for more information.

Reference Wind Velocity

The reference wind velocity is the product of: The Basic wind velocity, the Direction Factor (Cdir), the Seasonal Factor (Ctem), and the Altitude Factor (Calt). Refer to the local code and the Eurocode for more information on the appropriate magnitude of these values

Cpe Coefficient

The Cpe coefficient is calculated based on the dimensions provided by the engineer.

Note: The Cpe value is applied throughout the entire height of the structure and does not adjust at each story according to the story dimensions.

Building Dimensions

This is the dimension used to calculate the external pressure coefficient, Cpe. The default values are the dimensions of the building at the ground level.

Generate Additional Load Cases for Analysis with Tension-Only Members

RAM Frame utilizes a nonlinear analysis algorithm to keep track of tension-only members during solution of the structural model under applied loads. Since the process has a nonlinear (iterative) nature, analysis results can not be simply superposed with other results as in load combination option in RAM Frame. Therefore, each lateral load case (wind or seismic) are solved separately.

Since the direction of the lateral loads become important in an iterative analysis, RAM Frame provides an option such that additional load cases can be created upon user request. When Generate Additional Load Cases for Analysis with Tension-Only Members in generating lateral load cases (wind and seismic load cases only) is invoked, additional load cases are created. For instance, there are 12 load cases generated for a regular IBC 2000 (ASCE 7-98) Wind load case. If this box is checked, the number of the load cases becomes 22. Additional load cases are created to account for directional effects of applied loads so that the most severe loading case is captured.

Eurocode ENV1991-2-4:1995

Conceptual example of additional load cases for tension-only members