In LAVA, the Methodology tab allows you setup all the parameters for calculating the applied loads for lateral and snow.
Method
LAVA has Flexible, Rigid or an Envelope of the two methods. You can select the methodology for the entire model.
Seismic Loads
This tab allows you to apply seismic loads and enter the factors for the load calculations.
Apply Seismic Loads: When checked, LAVA will include seismic load combination into calculation. Default to be checked.
Adjustment Factor: User can input overall adjustment factor for remodel or historical project. Default to be 1.
Seismic Analysis Procedure: The selection here cannot be edited. To make changes, go to Project Definition - Criteria - Seismic Criteria.
East-West (X dir) Transverse (North-South (Y dir) Longitudinal tab is similar)
Seismic importance factor, Ie: Cannot be edited. To make changes, go to Project Definition - Criteria - Base Criteria, and modify the Risk Category.
Response Modification, R: Response modification coefficient. Default to be 6.5.
Allowed story drift factor: Default to be 0.02.
Overstrength factor, Omega: Default to be 2.50.
Redundancy factor, Rho: Default to be 1
Deflection amplification factor, Cd: Default to be 4.00
Calc button: User can push Calc button to obtain Cs value basing on input above.
Copy inputs to y dir (or x dir): This is a shortcut if inputs are the same for both X and Y direction. Press this link, data in this tab will be copied to all fields in Y direction (or X direction).
Irregular Structure ASCE 7-22 Sec 12.3.3.5: Check this option if the structure is irregular, and seismic force for collector will be increased by 25% per 12.3.3.5.
Vertical Distribution
Use Snow Load (%): User can choose to include snow load to seismic weight per ASCE 7-22, Chapter 12.7.2.4. Default to be 20.
Vertical distribution will be updated after the model is complete.
Story Drift
Allowable Story Drift: User to input value per ASCE 7-22 Table 12.12-1. Default to be 0.02 (All other structures).
Enable Deflection limit for Story Drift: when checked, LAVA will display failure warning if shear wall deflection is over story drift limit. Default to be checked.
Wind
Apply Wind Loads: When checked, LAVA will include wind load combination into calculation. Default to be checked.
Adjustment Factor: User can input overall adjustment factor for remodel or historical project. Default to be 1.
Snow
Apply Snow Loads: When checked, LAVA will include snow load combination into calculation. Default to be unchecked.
At this time, LAVA only applies loads for snow assuming a flat roof configuration. If the roof is sloped, LAVA will still consider it flat for snow which is conservative.
Please note: structural members modeled before this item was checked will NOT be calculated with snow load combination. User must include pertinent snow load combinations manually if required. For example, if user needs to calculate a beam with snow load, but this beam was modeled before checking ‘Apply Snow Loads’: go to ‘Load Combo’ tab, and uncheck pertinent snow load combinations under ‘Exclude Regular Load Combinations’.
