China GB50011-2001
| Setting | Description | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Load Case | States the Label of the load case being defined. | ||||||||||||||
| Exposure | Select the appropriate exposure category from the drop-down list. The exposure category reflects the characteristics of ground surface irregularities arising from natural topography and vegetation and of the constructed features at the site in which the building will be constructed. See building code 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. |
||||||||||||||
| Dynamic Effect Factor |
Dynamic effect factor,βz, is calculated at a
location height z according to the following equation:
|
||||||||||||||
| Shape Factors | Building shape factors can be defined for X and Y - directions. Note that These coefficients indicate windward and leeward wind surface factors. | ||||||||||||||
| Wind Fluctuation Factor | Three options are provided for wind fluctuation factor. | ||||||||||||||
| Wind Reference Pressure | Basic wind pressure (kN/m2 or psf) | ||||||||||||||
| Adjustment Coefficient | This coefficient is applied directly to μz, the wind load variant factor at height z. | ||||||||||||||
| Structure Period | Structure periods can be automatically calculated by the program for both X and Y direction (note that the program considers period that is based on the Eigen mode (i.e., mode shape) with highest building mass participation). Or, the user can enter structure period for X and Y direction separately. Note that if the 1st option is chosen (Use Calculated T), then the period multiplier is directly applied to calculated period (by default, it is 1.0). | ||||||||||||||
| 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. |
