In this case, the R value for the concrete pedestal would be input in the Seismic Load generator. In this case, two sets of load combinations would be created, one set in which only the Wood design check-box would be checked in the Load Combinations spreadsheet and one set in which only the Concrete design check-box is checked. This can be typical with a concrete pedestal supporting a wood structure. There are situations where the lower portion of the structure may have a different R value than the upper portion.
![eccentrically loaded footing risa 3d eccentrically loaded footing risa 3d](http://3.bp.blogspot.com/--xcSMkQ8tfE/UKPFigTKV9I/AAAAAAAAA4s/bxtzjNDCQog/s1600/2.gif)
T represents the input natural periods in each lateral direction. For reference, sections of the 2016 edition of ASCE 7 will be cited to explain the various entries.
ECCENTRICALLY LOADED FOOTING RISA 3D CODE
Seismic Load ParametersĬode currently allows you to choose the code which will be used for seismic load generation. Type in Search keywords: Generate Seismic. The Load Combination specified as the Seismic Weight LC entered in the Seismic Loadsįor additional advice on this topic, please see the RISA Tips & Tricks webpage at /post/support. The weight used for the calculation of seismic loads is based solely upon The parameters used in the seismic calculations may be viewed or changed by selecting Seismic from the Load Generators section of the Advanced tab. To get here click the button in the Load Combinations spreadsheet.įor additional advice on this topic, please see the RISA Tips & Tricks webpage at /post/support. The total seismic weight can be viewed using the Scaling Factor Dialog. The base shear is always computed using the total seismic weight.
![eccentrically loaded footing risa 3d eccentrically loaded footing risa 3d](http://www.ce-ref.com/Foundation/Spread_footing/Size_footing/Images/size_f1.gif)
![eccentrically loaded footing risa 3d eccentrically loaded footing risa 3d](https://img.youtube.com/vi/87kTwkRjEcg/hqdefault.jpg)
The total seismic weight of the whole structure is the sum of the seismic weights associated with all diaphragms and the weight associated with the base level. Any weight, or load included in the specified load combination, supported between diaphragms is distributed to the diaphragm above and below in inverse proportion to its distance from each diaphragm. While computing the seismic weight at a particular diaphragm, the self weight of the members/columns and plates between any two diaphragms is equally distributed amongst these diaphragms. The Seismic Weight of each diaphragm is the total tributary weight associated with it depending on the Load Combination chosen for calculating these forces on the Seismic Loads dialog box. Otherwise the eccentric BLCs that have been generated will never actually be applied.
![eccentrically loaded footing risa 3d eccentrically loaded footing risa 3d](https://i.ytimg.com/vi/GXEgHCQyx5Y/maxresdefault.jpg)
ECCENTRICALLY LOADED FOOTING RISA 3D GENERATOR
If you plan on using the Load Combination Generator in the Load Combinations spreadsheet, you must use the "X and Z w/Eccentric" Seismic Load option.