December 17, 2021

Load Combination Generator in ADAPT-Builder

With the release of ADAPT-Builder v21, a new load combination generator (LC Generator) provides users the option to automatically generate code compliant load combinations for use in the analysis and design of an ADAPT-Builder model. Included in this feature, is the ability to include automatic reversal of seismic and/or wind loads. In addition, the LC Generator includes options to add ASCE compliant combinations for the ACI code.

The LC Generator is implemented for all design codes available within ADAPT-Builder. ASCE specific combination options are available for all ACI codes with the exception of ACI 318-99.

By default, the new LC Generator gives users the following options (which can be enabled or disabled) when automatically generating required design code combinations:

Design State: ULS (Strength Level) or SLS (Serviceability Level) Combinations
Reversible: When selected, two combinations for each wind/seismic load combination will be created (each with opposite signage)
ASCE Combinations: Combinations based on ASCE 7 with specific options for bi-directional and eccentric load combinations
Vertical/Horizontal Seismic Load Effects: Application of Vertical/Horizontal seismic load effects according to ASCE 7 12.4.2.3

Example

The default load combinations (gravity) included by the program when the ACI 318-19 design code is selected are as follows:

Select the options in the LC Generator to have the program create load combinations for strength and serviceability, including both wind and seismic load effects. In this example the following options are used:

Note: To unlock the Wind load Options ASCE Cases section, as shown above, the user must assign wind loads, as building loads, in two orthogonal directions to the model.

With the above selections made, clicking "Add" will then generate an additional 68 load combinations for evaluation during analysis and design. Some of the load combinations generated are visible in the figure below.

For more information on the LC Generator included in ADAPT-Builder v21, click the link below to review the ADAPT-Builder Help File and review the video included below:

Tags: ADAPT-Builder, Loads, ADAPT, New Release, Load Combinations, New

September 29, 2021 | RISA-3D, RISA-2D, Load Combinations, New

Creating Custom Load Combinations (VIDEO)

RISA-3D, RISAFloor and RISAFoundation allow users to create custom load combination sets by modifying and expanding the underlying XML file used by the Load Combination Generator. To learn more, review the video and article below: The Load Combinations for each region are contained in an XML file which can be opened and edited using a standard spreadsheet program. An example of one of these XML files is shown below: The name of the file itself becomes the name of the Load Combination Region that appears in the Load Combination Generator. Each XML file has a series of “worksheets” and the name of each worksheet will be the name of the Load Combination Code that appears in the Load Combination Generator. In addition to the standard load combination codes that exist by default in RISA-3D, new codes can be manually added in order to expedite the creation of load combinations. An example of this is the use of the TIA-222-H, Standard for Antennas and the Supporting Structures for Antennas and Small Wind Turbines. To begin, open the appropriate Load Combination Region file from the following folder: C:\RISA User Data\YOURNAME\Load Combinations Once the file is open, add a new tab for the…

March 27, 2013 | RISA-3D, Loads, RISA-2D, Load Combinations, New

Nesting Load Combinations

The Load Combinations spreadsheet in RISA-3D is limited to ten columns of BLC and Factor combinations. However, there are times where you may need to include additional entries to your Load Combination. To do this, you can simply “nest” your load combinations. This means that if you need more than eight BLC entries in a single load combination, you can define the common BLCs (such as Self Weight, DL, and/or LL) in one load combination that you can then reference in the other load combinations. Entering “Lnn” in the BLC field will include all the BLCs (and their factors) from the load combination on line “nn” of the spreadsheet, thereby “nesting” the combination. This can also be used to simplify your input. For instance, you may have a model that needs to combine the effects of static loads and moving loads, or static loads and the Response Spectra results, but because of space limitations in the spreadsheet, it is impossible to fit them all into one row. Additionally, while investigating the performance of a structure, you may need to multiple entire load combinations by a "safety factor". In this example, the load combination (L22) is given additional factoring and has…

June 16, 2020 | Loads, Load Combinations, New, Basic Load Case, Load Category

Understanding differences between Basic Load Cases, Load Categories…

One of the questions our support team receives often is the difference between Basic Load Cases (BLC), Load Categories and Load Combinations (LC). Understanding how these containers are used and how they work together when loading a structure is an essential part of creating an accurate model in RISA. Basic Load Cases (BLC) When loads are defined, they are assigned into Basic Load Cases (BLC's). BLCs are the basic container of the final load combinations applied to the structure. A BLC can consist of any type of load; such as nodal loads, distributed loads, member point loads, surface loads, etc. The Basic Load Cases (BLC) can be assigned to different Load Categories such as Dead Load (DL) and Live Load (LL). It is also possible to assign different BLCs to the same Load Category. The BLCs and Load Categories can be used together to define Load Combinations that will be used for the analysis. Load Categories Load Categories are predefined groups in the program such as Dead Load (DL), Live Load (LL) and Earthquake Load (EL) that cannot be modified or added to by users of the program. Many of these groups are associated with IBC and ASCE 7 provisions…